a
School of Chemistry
Research Report
For the Academic Period
1 JANUARY 2008 – 31 DECEMBER 2009
http://www.tau.ac.il/chemistry
■ Organic Chemistry
Prof. Shmuel Carmeli
Technical Staff
U
Dr. Yocheved Rahamim
Doctoral Students
U
Shiri Gesner
Avi Raveh
Marina Lifshitz
Ela Zafrir
Ina Halphin (with Prof. Micha Ilan)
Margarita Vagman
Simi Adiv
Shira Peer
Olga Pogrebinsky
Masters Students
U
Elazar Cohen
Anat Lodin
Dimitry Kovalerchik
Michal Issac
Research Projects
U
Our research interest lies in the development of natural products as pharmaceutical
leads and elucidating their ecological role in the producing organisms. We exploit two
groups of organisms as the source for the novel natural products we study:
cyanobacteria, from terrestrial, fresh water and marine environments and fungi,
associated with marine invertebrate.
Natural products are an important source for
new pharmaceuticals
and
pharmaceutical “lead” compounds. The overwhelming majority of active compounds
were derived from terrestrial streptomycetes and fungi, although additional significant
sources include other bacteria and plants. A major problem with focusing on these
sources in drug discovery programs is the rediscovery of previously described natural
products. One of the major strategies now being explored to reduce the rate of
reisolation of known compounds is the examination of other, essentially unexploited,
sources. Marine natural products are an excellent example of such a source that
produced a handful of pharmaceutical leads and drugs in different stages of
development, especially in the field of anticancer drugs. Cyanobacteria (blue-green
algae) are a diverse group of cultivable microorganisms that are rich in novel
bioactive agents, but have been largely ignored by both the pharmaceutical industry
and academic research. Currently, three cyanobacteria-derived metabolites;
dollastatin-10, cryptomycin-52 and curacin A, are in development as anticancer
drugs. Marine microbes, bacteria and fungi, recently immerged as promising sources
for novel pharmaceuticals that differ from the chemistry of their terrestrial
counterparts.
Anatoxin A, a depolarizing neuromuscular blocking agent produced by cultures of the
filamentous cyanobacterium Anabaena flos-aquae clone NRC-44-1, is the first (1977)
cyanobacteria natural product to be structurally identified. Microcystis aeruginosa, a
colonial cyanobacterium that produces several hepatotoxic cyclic heptapeptides
called microcystins, is the most common cyanobacteria found in fresh-water and has
been responsible for most poisonings by this class of microorganisms. While such a
history may discourage some from investigating cyanobacteria natural products, it is
also indicative of a rich source of novel secondary metabolites, which may be
applicable to the development of new pharmaceuticals. In the last two decades over
five hundred unusual biologically active natural products have been described from
cyanobacteria. In this area, we currently run two parallel research projects; one
focused on the isolation of biologically active natural products from cultured
cyanobacteria strains and large masses of natural blooms that we collect in nature
(ISF, in collaboration with Prof. Eliezer Flescher, Faculty of Medicine, TAU) and the
second aimed at understanding the ecological role of cyanobacteria toxins and
associated natural products produced by water bloom-forming cyanobacteria.
Throughout, we studied cyanobacterial extracts for antimicrobial, anticancer and
inhibition of HIV-RT activity. In more resent years, we have been involved in the High
Throughput Screening (HTS) Project at Tel-Aviv University (financed by the Israel
Ministry of Science). This project allows us to screen in a broader scope using more
sophisticated assays that we cannot run in our laboratory and led to the isolation of
many inhibitors of metallo-, serine- and cystein-proteases, from fresh-water
cyanobacterial blooms. As a consequence, we are currently involved (ISF grant
2003-2005) in a study to isolate aspartyl- metallo-, serine- and cystein-protease
inhibitors from cultured marine and terrestrial cyanobacteria and their utilization as
anticancer drugs. Our ongoing collaboration with the HTS unit is aimed at the
isolation of cyanobacteria natural products with p53- and cap-independent apoptotic
activity and solid tumor selective anticancer activity.
Cyanobacterial blooms in aquatic environments are a matter of serious concern since
their occurrence is related to eutrophication processes. While blooms are unpleasant
both visually and due to released odour and taste factors, certain metabolites
produced by some cyanobacterial species have adverse effects on higher organisms.
The chemical structures of these toxic metabolites, and the mode of toxicity of most
of them, have been elucidated. Cyanobacterial toxins can be classified according to
their chemical structures as cyclic peptides, alkaloids and lipopolysaccharides but are
more commonly discussed in terms of their toxicity to animals. While there are
several dermatotoxins produced primarily by benthic marine cyanobacteria, most
cyanotoxins are classified as either hepatotoxins or neurotoxins.
Our interest in this subject was raised from an outbreak of a toxic waterbloom of the
cyanobacterium Aphanizomenon ovalisporum (Forti) in lake Kinneret in late 1994.
We initiated a study in collabortion with Dr. Sukenik from ILOR and Dr. Teltsch from
Mekorot Water Company, to elucidated the structure and toxicity of its toxins. From
this cyanobacterium we isolated the known toxin, cylindrospermopsin, previously
isolated from Cylindrospermopsis raciborskii (Woloszynska) and Umezakia natans
(Watanabe),
along
with
its
new
epimer,
7-epicylindrospermopsin.
Cylindrospermopsin’s toxic effects are recognized primarily in the liver but also in the
kidney, thymus, heart and spleen. The toxicology and biochemical action of
cylindrospermopsin has not yet been fully elucidated. The seasonal occurrence of
cylindrospermopsin-producing A. ovalisporum in Lake Kinneret imposes a serious
threat to the water quality of the major reservoir of fresh water in Israel. A few years
ago, in order to establish guidelines for cylindrospermopsin levels in drinking water,
we initiated a survey to assess its oral acute and chronic toxicity (in collaboration with
Dr. Sukenik from ILOR and Dr. Werman from The Technion, Haifa).
This project led us to the study of toxic and non-toxic water blooms of Microcystis
aeruginosa in Israeli’s water bodies. We found that most blooms, toxic and non-toxic,
contain substantial amounts of five different groups of inhibitors of proteolyticenzymes. Quantification of the relative amounts of toxins and protease inhibitors in
the cells of toxic blooms established a ratio of 1:50, respectively. Studies, of Drs.
Wiegand and Pflugmacher (from Berlin) in collaboration with us, on the effects of
microcin SF608 and microcystin-LR on aquatic organisms, shed some light on the
ecological role of the protease inhibitors in toxic cyanobacteria. Microcin SF608
enhances the activity of microcystin-LR by inhibiting the conversion of apoglutathione-S-transferase to its active form and thus preventing the detoxification of
the microcystins by conjugation to glutathione. Studies on the role of these protease
inhibitors continue.
It was suggested in the literature that toxin-producing cyanobacteria might have
substantial ecological advantage via an array of chemicals, which may eliminate
phytoplankton competitors and maintain their toxic bloom. Several allelochemicals
were already isolated from few cyanobacteria species, their structure was identified
and their mode of action was established. Recent studies (in collaboration with Sukenik
and
Kaplan)
cyanobacterium
demonstrated
a
Microcystis
sp.
novel
allelopathic
mechanism
inhibited photosynthesis
whereby
the
in the fresh water
dinoflagellate Peridinium gatunense by abolishing internal carbonic anhydrase activity.
Thus, the presence of Microcystis during the early stage of Peridinium bloom, in Lake
Kinerrret, could induce CO 2 limitation despite the high availability of CO 2 . Such
conditions lead to a substantial and fast accumulation of ROS in Peridinium and
eventually prevent the development of a competing population. Following the inhibition
of photosynthesis in P. gatunense, we isolated a novel allelochemical from extracts of
a laboratory cultured Microcystis sp. that was isolated from Lake Kinerret. Currently,
we study (in collaboration with Sukenik and Kaplan) the allelopathic effects of extracts
of, P. gatunense and some cyanobacteria from our culture collection, on Lake Kinerret
Microcystis sp. (BMFB 2006-2009 and MOST 2007-2010) in collaboration with Sukenik
and Kaplan). In the frame of this research we wish to develop a methodology for the
biological control of toxic cyanobacterial blooms in fresh-water lakes.
With pharmaceutical research and development as a significant driving force, the
1970’s marked the beginning of a large wave of remarkable discoveries of a large
number of biologically active compounds isolated from marine organisms. This
research resulted in the isolation and identification of thousands of new compounds
with
several
clinically
useful
drugs,
investigational
drug
candidates,
and
pharmacological tools based on these marine natural products. Only recently,
though, more efforts have been invested in studies aimed at examining the role some
of these compounds have in their natural environment, thus establishing the field of
marine chemical ecology. These latter studies have focused mainly on the effects
products of one organism have on others (e.g. feeding deterrence or antiovergrowth), with some studies proceeding to isolate and identify the compound
responsible for such activities. Throughout, we studied marine bacteria as a source
for pharmaceutically active natural products and the biosynthetic producers of some
biologically active natural products that were isolated from sponges, as well as, some
ecological aspects of sponge- and fish-derived metabolites. More recently, we are
involved (ISF 2006-2010, together with Prof. Ilan and Prof. Yarden) in a study to
explore the natural products derived from sponge-associated fungi and to elucidate
their ecological role. Deciphering the chemical ecology of the sponge niche will prove
a significant step in understanding other marine and terrestrial niches, while at the
same time provide a unique platform for exploiting novel compounds for biomedical
use.
Figure. (a) A colony of Aspergillus sydowii, the causal agent of (b) the gorgonian sea fan
(Gorgonia ventalina) death (necrotic rings). (c) The marine sponge Spongia obscura.
Collaborations
1.
Dr. Assaf Sukenik (National Institute of Oceanography, Haifa and Kinneret
Limnological Laboratory, Tabha), Dr. Ora Hadas (Kinneret Limnological
Laboratory, Tabha) and Prof. Aaron Kaplan (The Hebrew University,
Jerusalem) on Toxic Cyanobacterial Blooms in Water Reservoir.
2.
Dr. Micha Ilan (Dept. of Zoology) and Prof. Odded Yarden (Faculty of
Agriculture, Hebrew University, Rehovot) on Marine Fungai Metabolites.
Research Grants
2006-2009
BMFB -
Methodology to eliminate toxic cyanobacterial blooms in
water bodies.
Kaplan, A.; Carmeli S.; Sukenik, A.; Dittmann, E.; Borner, T.
2006-2010
ISF - Chemical Ecology of Sponge-Associated Fungi.
Ilan, M.; Yarden O.; Carmeli, S.
2006-2010
ISF - Discovery of Anticancer Agents from Cyanobacteria.
Carmeli, S. ; Flescher E.
2007-2010
MOST - Control of cyanobacterial populations as a mean to avoid
deterioration of the water quality in Lake Kinneret.
Kaplan, A.; Sukenik, A.; Carmeli S.
2007
Wolfson Foundation - MALDI Time-of-Flight High Resolution Mass
Spectrometer.
2008
Dr. Rimond Sackler - High Resolution Mass Spectrometer, Sackler
Biophysics Fund.
Publications
1.
S. Gesner-Apter and S. Carmeli.
Three Novel Metabolites from a Bloom of the Cyanobacteria Microcystis sp.
Tetrahedron 64, 6628-6634 ( 2008).
2.
B. Sedmak, S. Carmeli, T. Elersek.
“Non-toxic” cyclic peptides induce lysis of cyanobacteria – an efective cell population
density control mechanism in cyanobacterial blooms.
Microbial Ecology, 56, 201-209 (2008).
3.
B. Sedmak, T. Elersek, O. Grach-Pogrebinsky, S. Carmeli, N. Sever, T. Lah.
Ecotoxicologically relevent cyclic peptides from cyanobacterial bloom (Planktothrix
rubescence) – a threat to human and environmental health.
Radiology Oncology, 42, 102-113 (2008).
4.
O. Grach-Pogrebinsky and S. Carmeli.
Three Novel Anabaenopeptins from the Cyanobacterium Anabaena sp.
Tetrahedron, 64, 10233-10238 (2008).
5.
A. Raveh and S. Carmeli.
Two novel biological active modified peptides from the cyanobacterium Microcystis sp.
Phytochemistry Letters, 2, 10-14 (2009).
6.
N. Ein-Gil, M. Ilan, S. Carmeli, G.W. Smith, J.R. Pawlik and O. Yarden.
Presence of Aspergillus sydowii, a pathogen of gorgonian sea-fans in the marine
sponge Spongia obscura.
The ISME Journal, 3, 752-755 (2009).
7.
S. Gesner-Apter and S. Carmeli.
Nine New Protease Inhibitors from a Water Bloom of the Cyanobacterium Microcystis
aeruginosa
J. Nat. Prod, 72, 1429-1436 (2009).
0B
1B
8.
B. Sedmak, S. Carmeli, M. Pompe-Novak, M. Tusek-Znidaric, O. Grach-Pogrebinsky, T.
Elersek, M. C, Zuzek, A. Bubik, R. Frangez
Cyanobacterial cytoskeleton immunostaining: the detection of cyanobacterial cell lysis
induced by planktopeptin BL1125
J. Plankton Res, 31, 1321-1330 (2009).
9.
H. Eilenberg, S. Pnini-Cohen, Y. Rahamim, E. Sionov, E. Segal, S. Carmeli, A.
Zilberstein.
Induced Production of Antifungal Naphthoquinones in the Pitchers of the Carnivorous
Plant Nepenthes khasiana.
J. Exp. Botany, DOI: 10/1093/jxb/erp359 (2009).
9.
Z. Paz, M. Komon-Zelazowska, I.S. Druzhinina, M.M. Aveskamp, A. Schnaiderman, Y.
Aluma, S. Carmeli, M. Ilan, O. Yarden.
Diversity and potential antifungal properties of fungi associated with a Mediterranean
sponge.
Fungal Diversity, In press (2009).
10.
E. Vash, C. Ziv, S. Carmeli, O. Yarden.
The NDR kinase DBF2 is Involved in Regulation of Mitosis, Conidial Development and
Glycogen Metabolism in Neurospora crassa.
Eukaryotic Cell, In Press (2009).
■ Organic Chemistry
Prof. Yoram Cohen, Head of School
Web site: http://www.tau.ac.il/~ycoheng/
Reaserch Asistant
Dr. Liat Avram
Doctoral Students
Amnon Bar-Shir
Einat Wirtheim
Sarit Slovak
Noam Shemesh
Masters Students
Tal Sarid
Danna Krepel
Debbie Anaby
Tal Adiri
Research Projects
Our research program encompasses two major fields: Supramolecular chemistry
and applications of MRS and MRI in neuroscience. The following topics are
currently being investigated:
NMR Diffusion Measurements in Supramolecular Chemistry: The advance of
supramolecular chemistry "call" for additional analytical methods to better
characterize the obtained structure in solution. This "call" is even more pronounced
for labile dynamic multi-component systems. For more than a decade now we have
been using diffusion NMR to probe supramolecular systems both in organic
solvents and in aqueous solutions. In the past we have used diffusion NMR to
study, inter alia, crown-ethers, cryptands and CD complexes, CD based rotaxanes,
rosettes and dimeric capsules of tetraureacalix[4]arenes. Recently we have used
this approach to probe the structure of hydrogen-bound supramolecular polymers in
solution and to study the structure of porphyrin-calixarene assemblies. Complexes
of cucurbituril CB[n] with different guests were also studied very recently with
diffusion NMR.
Hydrogen Bond Molecular Capsules: Molecules within molecules. Molecular
capsules are capable of totally encapsulating molecules thus isolating them from
the bulk. As such they can be used a nanoreactors. We are currently using diffusion
NMR to characterize large hydrogen bond molecular capsules of resorcin[4]arenes
and pyrogallol[4]arenes. We study in detail their self-assembly, structure, stability
and guests’ affinity. Recently we become interested in the self-recognition in such
self-assembly processes and in their interaction with nano-surfaces. We were also
able to show that octahydroxypyridine[4]arene also forms hexameric capsule in
solution. The interaction of such hexameric capsules with different guests such as
alcohols, amines and organic acids are also studied in a future goal to use these
capsules as nanoreactors for reaction between these guests. For example, recently
we could demonstrate that diffusion NMR enables one to map alcohol sites in such
hexameric capsules and to determine if they are encapsulated or are part of the
backbone of the hexameric capsules.
MR Diffusion Spectroscopy and Imaging in Model Systems and in the CNS:
Restricted diffusion can be an excellent reporter for dimensions that are much
smaller than the dimensions of typical MRI voxels. We use NMR to study restricted
diffusion of water and metabolites both in vitro and in vivo to obtain microstructural
information in neuronal tissues in general and in neuronal fibers in particular. As a
crucial step towards gleaning microstructural information in neuronal tissue, we
investigate restricted diffusion in phantoms in which the ground-truth is known apriori. The aims of these studies are to assess the accuracy of the microstructural
information that can be obtained using different approaches. Moreover, we are
devising new MR imaging techniques which will enable in vivo MR imaging of
specific structures and pathologies in the brain, which cannot be obtained by
conventional methods. Notably, we have been developing the double-Pulse-FieldGradient (d-PFG) approach, which has been suggested recently as a novel
methodology to overcome the limitations imposed by current diffusion MR methods.
We have been able to show that accurate compartmental dimensions can be
extracted in clinically feasible conditions. Moreover, we could show that the
diffusion-diffraction patterns of d-PFG methodology provide a means of obtaining
accurate sizes and even shapes in systems with size distributions even when they
are randomely oriented. Interestingly, we could show that such information can be
gleaned, in the presence of background gradient, when bipolar d-PFG sequences
are used. Our findings were recently extended to biological cell systems and we
are currently developing d-PFG imaging.
Application of High-b-values q-Space Diffusion-Weighted MRI (QSI) in White
Matter Associated Disorders: Early and more specific detection of neuronal
diseases is of paramount importance. In recent years we have demonstrated the
high sensitivity of the high-b-values q-space diffusion MRI (QSI) to minor changes
in axonal morphology and hence to early white matter associated disorders. This
approach, which was developed first in vitro, is also carried out on human subjects
using clinical scanners. In recent years this approach was used to study spinal cord
maturation, spinal cord trauma and the EAE model. In human subjects this
approach was used to study multiple sclerosis (MS) and different type of dementia.
Very recently this approach was used to study the spinal cords and the brains of
experimental model of myelin deficiency. Both myelin deficient (md) and Long
Evans Shakers (les) rats were studied. The brains of the les rats were compared to
their age matched controls in terms of three indices; displacement, probability and
kurtosis. This study shows that the displacement values were much smaller in the
control brain than in the les brain. This suggests that in the WM of the control brain
there is more restriction resulting in apparent shorter water diffusion. Despite the
very low myelin content in the les brains some restriction is observed, meaning that
myelin is not a prerequisite for observing restriction and even diffusion anisotropy in
neuronal tissues. We could demonstrate that myelin affect the diffusion
characteristics of water and its diffusion anisotropy in neuronal tissues in a time
dependent manner. In these studies, QSI indices were found to be more sensitive
to the underline pathology than DTI measures.
Displacement maps
µm
9
8
7
6
control
les
5
Cellular MRI of Stem Cells' Migration: Stem cells are considered to be very
promising candidates for treating neurological disorders of the CNS. One of the
main issues in stem cells therapy is determining their fate in the host tissue after
transplantation, and moreover, evaluating their migration and homing capabilities
towards impaired tissue. Here, we demonstrated with cellular MRI that
mesenchymal stem cells pre-labeled with magnetic nanoparticles can migrate to
Quinolinic acid induced lesion - a known model of Huntington disease (HD). Such
treatments are now being pursued in experimental model of Parkinson's disease
(PD).
Preparation of Target Specific MRI Contrast Agents: The future of medical
treatment requires, inter alia, better understanding of diseases on the molecular
levels and earlier and more specific diagnosis of disease. These can be achieved
in principle through the design of new specific molecular probes. Indeed in recent
years we have been witnessing an explosion in the development of cellular and
molecular imaging. Here we focus on the preparation of target specific MRI
contrast agents for both cellular and more importantly molecular imaging of the
CNS using MRI.
Current Collaborations
1.
Prof. Peter Basser, National Institute of Health (NIH), NICHD/LIMB Section on
Tissue Biophysics, Building 13, Room 3N-17 Bethesda, MD 20892-5766, USA.
2.
Prof. Melchiorre Parisi, Departemento di Chimica Organica & Biologica, Universita
di Massina, Italy.
3.
Profs. Eldad Melamed and Daniel Offen, Laboratory of Neurosciences, Felsenstein
Medical Research Center, Department of Neurology, Rabin Medical Center,
Sackler Faculty of Medicine, Tel Aviv University.
Membership in Learned Societies
1.
ICS- Israel Chemistry Society.
2.
ISFN- Israel Society For Neurosciennces
3.
ISMRM- International Society of Magnetic Resonance in Medicine.
4.
ACS- American Chemical Society.
Research Grants
2007-2011
ISF, Self-Assembly of Hydrogen-Bond Molecular Capsules by
Diffusion NMR.
2004-2008
BSF, Restricted and Anisotropic Diffusion in Model Systems and
Neuronal Fibers.
2009-2011
Eu-STREP, "CONNECT". Consortium Of Neuroimagers for The NonInvasive Exploration of Brain Connectivity and Tractography.
2008-2009
IDF, MRI or Brain Intoxication.
Recognition
2010
Nominated Fellow of the International Society of Magnetic Resonance in
Medicine (ISMRM).
Publications
Articles
1.
2.
A. Bar-Shir, Y. Cohen,
The Effect of the Rotational Angle on MR Diffusion Parameters: Is the Minimal
Diffusivity a Better Parameter for Determining Fiber Orientation.
J. Magn. Reson., 190, 33-42 (2008).
A. Bar-Shir, Y. Cohen,
High b-Value q-Space Diffusion MRS of Nerves: Structural Information and
Comparison with Histology.
NMR Biomed., 21, 165-174 (2008).
3.
Y. Cohen, T. Evan-Salem, L. Avram,
Hydrogen-bonded Hexameric Capsules of Resorcin[4]arene, Pyrogallol[4]arene and
Octahydroxypyridine[4]arene are Abundant Structures in Organic Solvents: A View
from Diffusion NMR.
Supramolecular Chem., 20, 71-79 (2008).
4.
L. Avram, Y. Cohen,
Diffusion NMR of the Self-Assembly of Resorcin[4]arene in the Presence of Small
Alkylammonium Guests in Solution.
Org. Letters, 10, 1505-1508 (2008).
5.
A. Bar-Shir, Y. Cohen,
Crossing Fibers, Diffractions and Non-Homogeneous Magnetic Field: Correction of
Artifacts by Bipolar Gradient Pulses.
Magn. Reson. Imaging, 26, 801-808 (2008).
6.
L. Avram, E. Özarslan, Y. Assaf, A. Bar-Shir, Y. Cohen, P. J. Basser,
Three-Dimensional Water Diffusion within Impermeable Cylindrical Tubes: Theory
vs. MR Experiments.
NMR Biomed., 21, 888-898 (2008).
7.
O. Sadan, N. Shemesh, M. Bahat-Storma, E. Melamed, Y. Cohen, D. Offen,
Migartion of Neurotrofic Factors-Secreting Mesenchymal Stem Cells Towards a
Quinolinic Acid Lesion as Viewed by MRI.
Stem Cells, 26, 2542-2551 (2008).
8.
A. Bar-Shir, L. Avram, E. Özarslan, P. J. Basser and Y. Cohen,
The Effect of Diffusion Time and Pulse Gradient Duration Ratio on the Diffraction
Patterns and the Structural Information Extracted from the q-Space Diffusion
MR: Experiments and Simulations.
J. Magn. Reson., 194, 230-236 (2008).
9.
G. Gattuso, A. Notti, A. Pappalardo, M. F. Parisi, I. Pisagatti, S. Pappalardo, D.
Grozzo, A. Messina, Y.Cohen, S. Slovak,
Self-Assembly of Modular Homoditopic Bis-calix[5]arene and Long Chained α,ωAlkanediyldiammonium Components.
J. Org. Chem., 73, 7280-7289 (2008).
10.
N. Shemesh, Y. Cohen,
The Effect of Experimental Parameters on the Signal Decay in Double-PGSE
Experiments: Negative Diffractions and Enhancement of Structural Information.
J. Magn. Reson., 195, 153–161 (2008).
11.
N. Shemesh, E. Özarslan, P. J. Basser and Y. Cohen,
Measuring Small Compartmental Dimensions with Low-q Angular Double-PGSE
NMR: The Effect of Experimental Parameters on Signal Decay.
J. Magn. Reson., 189, 15-23 (2009).
12.
E. Wirtheim, L. Avram and Cohen Y,
Thio-Ether-Footed Resorcin[4]arenes: Self-Assembly in Solutions and Interaction
with Gold Nanoparticles as Viewed by Diffusion NMR.
Tetrahedron, 65, 7268-7276 (2009).
13.
14.
O. Sadan, N. Shemesh, Y. Cohen, E. Melamed, D. Offen,
Adult Neurotrofic Factors-Secreting Stem Cells: A Potential Novel Therapy for
Neurodegenerative Diseases.
Isr. Med. Assoc. J., 11, 201-204 (2009).
O. Sadan, M.Bahat-Stromza, Y. Barhum, Y. S. Levy, A. Pisnevsky, H. Peretz, A.
Bar Ilan, S. Bulvik, N. Shemesh, D. Krepel, Y. Cohen, E. Melamed, D. Offen,
Protective Effects of Neurotrophic Factors Secreting Cells in a 6OHDA
Rat Model of Parkinson Disease.
Stem Cells Dev., 18, 1179-1190 (2009).
15.
A. Bar-Shir, I. D. Duncan, Y. Cohen,
QSI and DTI of Excised Brains of Myelin-Deficient Rats.
NeuroImage, 48, 109-116 (2009).
16.
N. Shemesh, E. Özarslan, A. Bar-Shir, P. J. Basser, Y. Cohen,
Observation of Restricted Diffusion in the Presence of a Freely Diffusing
Compartment: Single- and Double-PFG MR Experiments.
J. Magn. Reson., 200, 214-225 (2009).
17.
N. Shemesh, O. Sadan, E. Melamed, D. Offen, Y. Cohen,
Longitudinal MRI and MRS Characterization of the Quinolinic Acid Lesion Rat
Model of Huntington’s Disease: Low Apparent Diffusion Coefficients After 49
Days and Spontaneous Recovery of N-Acetyl Aspartate Levels.
NMR in Biomed., 23, 196-206 (2010).
18.
A. Bar-Shir, N. Shemesh, R. Nussin-Manor, Y. Cohen,
Long Terapeutic Window in Sphenopalatine Ganglion Stimulated Ischemic Rats:
An MRI and MRS Study.
J. Magn. Reson. Imaging, Accepted for publication.
19.
S, Slovak, L. Avram, Y. Cohen,
"Encapsulated or not Encapsulated": Mapping Alcohol Sites in Hexameric
Capsules of Resorcin[4]arenes in Solution by Diffusion NMR.
Angew Chem. Int. Ed., 49, 428-431 (2010).
20.
N. Shemesh, E. Özarslan, P. J. Basser, Y. Cohen,
Detecting Diffusion-Diffraction Patterns in Size Distribution Phantoms Using
Double-Pulsed Field Gradient (d-FPG) NMR: Theory and Experiments.
J. Chem. Phys., 132, 034703 (1-12) (2010).
21.
N. Shemesh, E. Özarslan, M.E. Komlosh, P. J. Basser, Y. Cohen,
Gleaning New Microstructural Information from Double-PFG NMR and MRI NMR
in Biomed., Accepted for publication.
Book Chapters
1.
Y. Assaf, Y. Cohen,
Inferring Microstructural Information of White Matter from Diffusion MRI in
"Diffusion MRI: From Quantitative Measurement to In Vivo Neuroanatomy", H.
Johansen-Berg, T. E. J. Behrens Eds., Academic Press, pp. 127-146 (2009).
■ Organic Chemistry
Dr. Micha Fridman
Technical Staff
Dr. Maria Kremer
Doctoral Students
Silvy Winstein
Yifat Berko Zrihen
Masters Students
Pazit Shaul
Roi Rutenberg
Elinor Briner Goldstein
Research Projects
Our laboratory is interested in understanding biological processes using chemical tools. In
particular we are interested in the interface of glyco-chemistry and glyco-biology. There
are currently two ongoing projects in our laboratory:
The study of the molecular mechanism and directions to circumvent the toxic side
effects of anthracycline based chemotherapy using synthetic analogs:
Cardiotoxicity is a severe complication of cancer treatment by anthracyclines which are
amongst the most widely used anticancer agents. Unfortunately, the clinical use of
anthracycliness is limited by their acute and chronic cardiotoxicity. We aim to develop
formation of toxic metabolites which
are responsible for the severe cardio-toxic side
effects. Directions to differentiate undesired
side effects from desired antitumor activity are
being explored.
We are currently developing anthracycline analogs based on carbasugar (pseudosugar) mimics which replace the sugars found on the natural structures of
anthracyclines.
According to the suggested mechanisms, the carbasugar based
analogs will be stable to the reductive de-glycosidation metabolism in heart muscle
cells and thus toxic side effects will be prevented.
To date, we established a synthetic pathway for the preparation of pentosepyranoside-Aloe-emodin anthracycline analogs and using this pathway we completed
the synthesis several such analogs. We then tested the cytotoxic performance of the
novel analogs against several strains of cancer cell lines. The novel compounds were
found to have good potency against all of the tested cell lines with close to a 100%
cytotoxicity using concentrations lower than 8 micro molar.
In this research program we combine chemical, biochemical and cell biology tools to
offer new insights as well as directions for the design of antitumor agents with
reduced toxic side effects.
Utilizing aminoglycoside-modifying enzymes for the development of novel
aminoglycoside antibiotics analogs:
Aminoglycosides
antibiotics
are
commonly
broad-spectrum
used
for
the
treatment of serious bacterial infections.
Over six decades of clinical use has led to
the widespread emergence of bacterial
resistance to this family of drugs limiting
their efficacy in the clinic. Here we report
the development of a methodology that
utilizes aminoglycoside acetyltransferases
(AACs) and a variety of acyl-coenzyme A
analogs for the chemoenzymatic generation of N-acylated aminoglycoside analogs.
Generation of N-acylated aminoglycosides is followed by a simple qualitative test to
assess their potency as potentail antibacterials. The studied AACs (AAC(6’)-APH(2”)
and AAC(3)-IV) show diverse substrate promiscuity towards a variety of
aminoglycosides as well as acyl-coenzyme A analogs. The enzymes were also used
for the sequential generation of double N-acylated aminoglycosides. Following the
clinical success of the N-acylated amikacin and arbekacin, our chemoenzymatic
approach offers access to regio-selectively N-acylated aminoglycosides. Thus,
enzymes which evolved in bacteria to confer resistance to aminoglycoside antibiotics
are utilized as a synthetic tool to generate novel analogs of aminoglycosides with
superior antibacterial activity.
Collaborations
1.
Professor Flescher Eliezr. Department of Human Microbiology, School of
Medicine, Tel-Aviv University, Ramat Aviv, Israel.
2.
Dr. Sylvie Garneau Tsodikova. Life Sciences Institute, University Michigan at
Ann Arbor, Michigan. USA. 48109-2216.
Research Grants
2010-14
Marie Curie re-integration grant (IRG) 2010-2014.
2009-11
BSF (Collaboration with Dr. Garneau-Tsodikova.University of Michigan
at Ann Arbor).
Selected Publications
1.
Fridman Micha; Balibar Carl J; Kahne Daniel; Walsh Christopher T;
and Garneau-Tsodikova Sylvie.
Chemoenzymatic Formation of Novel Aminocoumarin Antibiotics by the
Enzymes CouN1 and CouN7.
Biochemistry, 46(28), 8462-8471 (2007).
2.
Catherine Leimkuhler, Micha Fridman, Tania Lupoli, Suzanne Walker,
Christopher T. Walsh and Daniel Kahne.
Characterizationof rhodosaminyl-transfer by the AknS/AknT glycosylation
complex and its use in reconstituting the biosynthetic pathway of
Aclacinomycin A.
Journal of the American Chemical Society, 29(34), 10546-10550 (2007).
3.
Tetsuya Tanikawa, Micha Fridman, Bridget K. Wagner, Wenjiang Zhu Brian
Faulk, Isaac C. Joseph Paul A. Clemons, Daniel Kahne.
Exploring the impact of stereochemical diversity on biological activity using
carbohydrate scaffolds.
Journal of the American Chemical Society, 131(14), 5075-5083 (2009).
4.
Green, Keith D.; Fridman, Micha; Garneau-Tsodikova, Sylvie.
hChAT: A Tool for the Chemoenzymatic Generation of Potential
cetyl/Butyrylcholinesterase Inhibitors.
ChemBioChem, 10(13), 2191-2194 (2009).
5.
Green Keith D. Green, Wenjing Chen, Jabob L. Houghton, Micha Fridman*,
Sylvie Garneau-Tsodikova/*
Exploring the Substrate Promiscuity of Drug-Modifying Enzymes for the
Chemoenzymatic Generation of N-Acylated Aminoglycosides.
ChemBioChem. 2009, accepted for publication. Cover page of January 2010
edition.
■ Organic Chemistry
Prof. (Emeritus) Benzion Fuchs
A new and expedient alkali carbonate catalyzed thioeterifying oligomerization
reactions of ethylenedithioglycol (ETG) to higher polythiaethylenethioglycols was put
forward. The most practical is K 2 CO 3 ; and similar catalyzed chain increases of the
dimer (DETG) and trimer (TrETG) were also found to occur in acetonitrile or water.
Eventually, ETG could be used in facile and inexpensive preparations of laboratory
quantities of the otherwise scarce and/or expensive DETG, TrETG, TETG and PETG
oligomers, thus also avoiding hazardous intermediates in the process. This opens the
way to clean ‘green’ chemistry protocols for the synthesis of the polythiaoligomers, macrocycles and their subproducts and to new approaches to templated and
Dynamic
Combinatorial
(SCH 2 CH 2 ) n S bridges.
Libraries
of
macrocycles
containing
manifolded
Research Interests
1.
Supramolecular Chemistry: New Host systems with Chiral Diacetal Cores.
Polythiacrown Macro- Giganto & Ultracyles. Chiral Recognition & Catalysis.
2.
Organic
Stereochemistry:
Structural
&
Conformational
Analysis.
Stereoelectronic Effects. Stereoselective Synthesis. Dynamic Combinatorial
Virtual Libraries of Chiral Unit Systems.
3.
Computational Chemistry: Theory vs. Experiment. MO and MM Methods.
4.
Organic Photochemistry: Photoinduced Rearrangements.
Collaborations
1.
Dr. N. G. Lemcoff, Ben Gurion University, Beer-Sheva
2.
Member of COST Chemistry Working Group D31, European Science
Foundation, 2005-2010
Membership in Learned Societies
1.
Israel Chemical Society.
2.
American Chemical Society.
Publications
Articles
1.
D. Berkovich-Berger, N. G. Lemcoff, S. Abramson, M. Grabarnik, S. Weinman,
B. Fuchs, N. G. Lemcoff, S. Weinman, B. Fuchs,
“Oligomerization of Ethanedithiol in Polythiacrown Chemistry 1. An Expedient
Approach to Oligothiaethylenethioglycols”.
Chem. Eur. J., In Press.
2.
M. Vardi, J. Oren, S. Abramson, S. Weinman, B. Fuchs,
"Stereoselective Photorearrangement Of Homoconjugated Spiroenediketones.
Access To Tricyclic [X.4.0] Systems".
Eur. J. Org. Chem., Submitted.
■ Organic Chemistry
Dr. Michael Gozin
Reaserch Associate
Dr. Ludmila Fadeev
Doctoral Students
Eyal Drug
Hanit Marom
Nataly Shraga
Masters Students
Shani Shoushan
Boaz Seemann
Yanai Popowski
Anna Karasik
Svetlana Antonov
Bogdan Belgorodsky
Research Projects
Dr. Michael Gozin's research activity is in the fields of Medicinal Chemistry, Protein
Chemistry and Forensic Chemistry.
1.
Medicinal Chemistry – Development of Receptor-targeted Potential
Therapeutic and Diagnostic Agents
The synthesis of water-soluble fullerene derivatives for various biomedical
applications is an active area of research in recent years. One of our projects is
focused on a preparation, characterization and evaluation of new NMDA receptorspecific antioxidants (such as novel fullerene derivative ABS75).
#1 RT: 0.03 AV: 1 NL: 2.59E5
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NH
~8
1118.0
1206.0
1250.0
1073.8
1293.9
1030.0
1337.9
986.0
1381.9
941.9
1425.9
897.9
1469.9
1471.0
632.6 720.6
1515.0
853.8
544.4
1603.0
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600
800
1000
1200
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1600
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m/z
This research is conducted in collaboration with Harvard Medical School. As was
shown in animal studies performed by our collaborators, these NMDA receptortargeted antioxidants have great potential to be developed as neuroprotecting
therapeutic agents for the treatment of various neurological disorders, such as
Multiple Sclerosis, Parkinson's and Alzheimer’s diseases.
Prostate Cancer continues to have the highest incidence rate of any other type of
cancer in men and it is the second leading cause of cancer deaths in male, with
approximately 220,000 new cases diagnosed each year only in US. The normal
development and maintenance of the prostate is dependent on androgen acting
through the androgen receptor (AR), which remains important in the development
and progression of prostate cancer. AR expression is maintained throughout prostate
cancer progression, and the majority of androgen-independent or hormone refractory
prostate cancers express AR. AR ligands can be divided into two main structural
classes, steroidal and non-steroidal, and into two different functional classes,
androgenic and antiandrogenic. Principal therapeutic approaches that are common
for progressive prostate cancer treatment and results in the regression of most
androgen-dependent tumors, include an androgen ablation monotherapy, surgical or
chemical castration with non-steroidal antiandrogens, such as Flutamide and
Bicalutamide. Presently, Bicalutamide is the leading antiandrogen used in clinical
practice and although it is given as a racemic mixture, the R enantiomer of the
Bicalutamide was found to have 30-fold higher binding affinity to the androgen
receptor than its S stereoisomer.
Our research presents an unprecedented synthesis of prostate-targeted nonsteroidal antiandrogen-DOTA-lanthanoid metal complexes designed for prostate
cancer imaging and radiotherapy. Specifically, Gd, Eu and Tb metal complexes of a
multipurpose ligand were prepared and characterized. Our preliminary in vivo
evaluation of Gd complex, as a prostate MRI contrast agent has been conducted in
mouse, bearing a prostate tumor. We believe that use of prostate-targeting ligand
complexes, containing appropriate radioactive metal ions, could be also very
promising for PET imaging of prostate tumors. Our study paves the way for the
introduction of novel "dual-purpose" receptor-targeted pharmaceutical precursors
(metal chelators), which, depending on a dosage and utilized metal ions, are
designed to be suitable for diagnostics or therapy. This research is conducted in
collaboration with the Department of Physiology and Pharmacology, School of
Medicine at Tel Aviv University and the Department of Imaging Radiology of Sheba
Medical Center.
2. Hybrid BioNanomaterials – Characterization and Function
Mucins are glycoproteins that constitute 80% of the organic components of mucus,
which coats many organs, including the respiratory, digestive, and reproductive tracts
and, in some amphibia, the skin. It is believed that the main function of these
glycoproteins is to protect epithelial cells from infection and dehydration as well as
from physical and chemical injuries. Although mucins exhibit a broad range of
adhesive interactions with various hydrophobic materials, including polycyclic
aromatic hydrocarbons, there has been no clear evidence that mucins are capable of
promoting chemical reactions. Here we demonstrated that under physiological
conditions, two representative mucins accelerated the rate of fatty acid ester
hydrolysis up to 337 times relative to the mucin-free reference reaction. Moreover,
under the same reaction conditions, a Diels-Alder reaction between N-propylmaleimide and anthracene was promoted by these glycoproteins. The latter reaction
does not occur in aqueous media without mucins, and the rate was accelerated up
200 times in the presence of a mucin relative to the rate of the reference process
performed in chloroform. Mucins consist of branched oligosaccharide chains
attached to a protein backbone. This unique structure was discovered to be critically
important to the rate acceleration, as various cyclic and noncyclic oligosaccharides
were far less efficient in promoting the same reactions.
The discovered property of mucins to accelerate organic chemical reactions provides
a new and unique example of natural nonenzymatic proteins capable of promoting
reactions of hydrophobic materials in aqueous solution. As heavily glycosylated
mucins showed unique properties in comparison with various oligosaccharides, we
proposed that mucins perform the task of dissolving the hydrophobic compound (with
subsequent promotion of organic reactions) by folding of their amorphous oligomeric
structure in order to create local hydrophobic environments in which such reactions
can take place. Furthermore, our results may lead to a better understanding of how
various highly reactive therapeutic agents undergo metabolic processes in a mucus
layer. Studies of mucin chemical reactivity are also relevant to development of
biocompatible materials for implantable devices, such as birth control devices,
orthodontic devices, digestive-tract-implantable devices, and contact lenses, all of
which have surfaces that come into direct, long-term interaction with mucus.
In recent years, the exposure of biological systems to various nanomaterials has
become an issue of great public concern. Although living organisms have arrays of
biological defense mechanisms against exposure to exogenous compounds, the
biochemical mechanisms allowing various nanomaterials to enter the body are not
well understood. A unique example of a typical mucosal glycoprotein capable of
binding and solubilizing nanomaterials in physiological solution is provided,
suggesting a possible route for entry into biological systems.
The anthropogenic combustion of wood, coal, liquid fuels, and waste results in the
emission of enormous amounts of carbon nanoparticles into the atmosphere. In
addition, the exposure of the environment and living organisms to carbon-based and
inorganic nanomaterials is expected to grow dramatically in the next few years as the
chemical industry plans to manufacture a variety of these materials in high volumes.
In contrast to poorly water-soluble polyaromatic hydrocarbons, which are well known
as
powerful
mutagens
and
carcinogens,
the
biological
effects
(transport,
bioaccumulation, and toxicity) of various nanomaterials have only just begun to be
explored. A few reported studies have addressed the toxicities of fullerene, carbon
nanotubes, and other nanomaterials. For example, it was shown that the pulmonary
toxicity of single- and multi-walled carbon nanotubes (MWNTs) delivered at high
doses and dose rates into the lower respiratory tract of rats and mice induced an
acute inflammatory response with granuloma formation and fibrosis as late effects. In
contrast, preliminary toxicology tests of fullerene-like WS 2 in rats showed no
apparent toxicity via oral, dermal, or inhalation administration. Although debatable,
acute toxicity studies of nano-colloidal suspensions of C 60 fullerene clusters in water
have been performed on several environmentally relevant species, such as
freshwater crustaceans and fish. It is expected that an array of biological defenses
should protect organisms from these materials. For example, it is believed that the
mucosal gel that covers the respiratory and gastrointestinal tracts should provide an
effective physical and chemical shield against a range of toxic materials. The primary
components of mucus are high-molecular-weight mucin glycoproteins that form
numerous covalent and noncovalent bonds with other mucin molecules to form a
mucus network. The condensed and complex microstructure of the mucus network
gives rise to a highly viscoelastic gel that significantly impedes the transport rates of
large macromolecules and nanoparticles. The fast rate of mucosal exchange (a few
days in the respiratory system and hours in the gastrointestinal system) offers an
effective natural protective and disposal mechanism for various potentially toxic
exogenous materials. We demonstrated that a representative mucin glycoprotein,
bovine submaxillary mucin, showed impressive and unique capabilities in the binding
and solubilizing of water-insoluble materials in physiological solutions. We showed
the possibility of introducing and delivering of such materials into biological systems.
Our results provide a unique example of a method by which hydrophobic materials
could be solubilized in a biological system and the possibility of a biochemical point
of entry of such materials into a living organism.
Publications
1.
Belgorodsky, B.; Drug, E.; Fadeev, L.; Hendler, N.; Mentovich, E.; Gozin, M.
"Mucin Complexes of Nanomaterials – First Biochemical Encounter"
Small 2009, in print.
2.
Mentovich, E.; Shraga, N.; Kalifa, I.; Tsukernik, A.; Hendler, N.; Gozin, M.;
Richter, S. J. Nanosci.
"High-yield Fabrication of Molecular Vertical Junctions".
Nanotech. 2009, accepted.
3.
Shraga, N.; Belgorodsky, B.; Gozin, M.
"Organic Reactions Promoted by Mucin Glycoproteins".
J. Am. Chem. Soc, 131(34), 12074-12075 (2008).
4.
Basso, A. S.; Frenkel, D.; Quintana, F. J.; Costa-Pinto, F. A.; Farez, M.;
Petrovic-Stojkovic, S.; Puckett, L.; Monsonego, A.; Engel, Y.; Bar-Shir, A.;
Gozin, M.; Weiner, H. L.
“A Novel Fullerene-NMDA-Receptor Antagonist Compound Reduces Axonal
Loss and Neurological Disability a Model of Progressive Multiple Sclerosis”.
J. Clin. Inv, 118(4), 1532-1543 (2008).
5.
Mentovich, E. D.; Chalifa, I.; Caster, A.; Holtzman, A.; Rosenberg, N.;
Marom, H.; Gozin, M.; Richter S.
“Multipeak Negative-Differential-Resistance Molecular Device”
Small, 4(1), 55-58 (2008).
6.
Drug, E.; Gozin, M. J.
“Catalytic Oxidation of Hydrazo Derivatives Promoted by TiCl 3 /HBr System”
Am. Chem. Soc. 129(45), 13784-13785 (2007).
7.
Belgorodsky, B.; Fadeev, L.; Kolsenik J.; Gozin, M.
“Bio-delivery of Fullerene Derivative”.
Bioconjugate Chem. 18(4), 1095-1100 (2007).
8.
Kolsenik, J.; Belgorodsky, B.; Fadeev, L.; Gozin, M.
“Can Apomyoglobin Form a Complex with a Spherical Ligand? Interactions
between Apo-myoglobin and [C 60 ]fullerene derivative”
J. Nanosci. Nanotech. 7, 1389-1394 (2007).
9.
Dahan, A.; Ashkenazi, T.; Kuznetsov, V.; Makievski, S.; Fadeev, L.; Bramson,
M.; Shokoroy, S.; Drug, E.; Marom, H.; Rozenshine-Kemelmakher, E.; Gozin,
M.
“Synthesis and Evaluation of a Pseudocyclic Tristhiourea-Based Anion Host”
J. Org. Chem., 72, 2289-2296 (2007).
10.
Engel, Y.; Dahan, A.; Rozenshine-Kemelmakher, E.; Gozin, M.
“Phenanthroline-Derived Ratiometric Chemosensor for Ureas”
J. Org. Chem. 72, 2318-2328 (2007).
■ Organic Chemistry
Prof. (Emeritus) Yoel Kashman
The Alexander and Klara Stransky Chair in NMR in Bioorganic
Chemistry.
Technical Staff
Dr. Amira Rudi
Yardena Abudi
Neta Avni
Doctoral Students
Hagit Shalom
Ashgan Bishara
Lee Goren
Masters Students
Dina Yeffet
Neta Avni
Research Projects
1. Isolation and structure elucidation of natural compounds from (a) marine sources,
mainly soft corals, sponges, tunicates and marine bacteria (b) terrestrial plants.
The structure of the compounds is achieved by 1D and 2D NMR techniques, MS
spectra as well as chemical degradations. The research is aimed at finding new
bioactive compounds.
2. Synthesis of cyclic endiamino and thioenamino peptides.
Collaborations
1.
Y. Benayahu - Department of Zoology, TAU.
2.
M. Aknin – Le Reunion and E. Gaydou- Marsellies, France.
3.
D. Newmann - School of Medicine, TAU.
4.
R. Ophir – Ben Gurion University.
5.
A. Elman - Volcani
Membership in Learned Societies
1.
Am. Chem. Soc.
2.
Am. Soc. of Pharmacognosy.
3.
Israel Chem. Soc.
Research Grants
2006-2009
ISF Cyclic endiamine peptides
Publications
1.
Ashgan Bishara, Amira Rudi, Maurice Aknin, Drorit Neumann, Nathalie BenCalifa and Yoel Kashman.
Salarins A and B and Tulearin A: New Cytotoxic Sponge-Derived
Macrolides. Organic Letters, 10 (2), 153-156 (2008).
2.
Moussaieff, Arieh; Shohami, Esther; Kashman, Yoel; Fride, Ester; Schmitz,
M, Lienhard; Renner, Florian; Fiebich, Bernd L; Munoz, Eduardo; Ben-Neriah,
Yinon; Mechoulam, Raphael.
Incensole acetate, a novel anti-inflammatory compound isolated from
Boswellia resin, inhibits nuclear factor-κ B activation.
Molecular Pharmacology, 72 (6), 1657-1664 (2007).
3.
Bishara, Ashgan; Yeffet, Dina; Sisso, Mor; Shmul, Guy; Schleyer, Michael;
Benayahu, Yehuda; Rudi, Amira; Kashman, Yoel.
Nardosinanols A-I and Lemnafricanol, Sesquiterpenes from Several Soft
Corals, Lemnalia sp., Peralemnalia clavata, lemnalia Africana, and Rhytisma
fulvum fulvum.
Journal of Natural Products, 71 (3), 375-380 (2008).
4.
Zeevi Ben-Yosef, Dafna; Kashman, Yoel; Benayahu, Yehuda.
Microsporine-like amino acids in zooxanthellate early developmental stages
of the soft coral Heteroxenia fuscescens.
Journal of Experimental Marine Biology and Ecology, 355 (1) 12-17 (2008).
5.
Sorek, Hagit; Zelikoff, Ayellet L.; Benayahu, Yehuda; Kashman, Yoel.
Axiplyns A-E, new sesquiterpene isothiocyanates from the marine sponge
Axinyssa aplyssinoides.
Tetrahedron Letters, 49 (14) 2200-2203 (2008).
6.
Bishara, Ashgan; Rudi, Amira; Aknin, Maurice; Neumann, Drorit; Ben-Califa,
Nathalie; Kashman, Yoel.
Salarin C, a new cytotoxic sponge-derived nitrogenous macrolide.
Tetrahedron Letters, 49 (28) 4355-4358 (2008).
7.
Bishara, Ashgan; Rudi, Amira; Aknin, Maurice; Neumann, Drorit; Ben-Califa,
Nathalie; Kashman, Yoel.
Taumycins A and B, Two Bioactive Lipodepsipeptides from the Madagascar
Sponge Fascaplysinopsis sp.
Organic Letters, 10(19), 4307-4309 (2008).
8.
Bensemhoun, Julia; Rudi, Amira; Bombarda, Isabelle; Gaydou, Emile M.;
Kashman, Yoel; Aknin, Maurice.
Flexusines A and B and Epimukulol from the Soft Coral Sarcophyton
flexuosum.
Journal of Natural Products, 71(7), 1262-1264 (2008).
9.
Moussaieff, Arieh; Rimmerman, Neta; Bregman, Tatiana; Straiker, Alex;
Felder, Christian C; Shoham, Shai; Kashman, Yoel; Huang, Susan; Lee,
Hyosang; Shohami, Esther; Mackie, Ken; Caterina, Michael J; Walker, J.
Michael; Fride, Ester; Mechoulam, Raphael. Incensole acetate, an
increase component, elicits psychoactivity by activating TRPV3 channels in
the brain.
FASEB Journal, 22(8), 3024-3034 (2008).
10.
Lee Goren; Doron Pappo; Israel Goldberg; Yoel Kashman.
Acyclic and Cyclic Thioenamino Peptides; Solution and Solid Phase
Synthesis.
Tetrahedron Lett, 50, 1048-1050 (2009).
11.
Sorek, Hagit; Rudi, Amira; Goldberg, Israel; Aknin, Maurice; Kashman,
Yoel.
Saldedines A and B, Dibromo Proaporphine Alkaloids from a Madagascan
Tunicate.
Journal of Natural Products, 72(4), 784-786 (2009).
12.
Kogon, Yael; Goren, Lee; Pappo, Doron; Rudi, Amira; Kashman, Yoel.
Cyclic endiamino peptides: a new synthesis of imidazopyrazines.
European Journal of Organic Chemistry, (12), 1852-1854 (2009).
13.
Bishara, Ashgan; Rudi, Amira; Goldberg, Israel; Aknin, Maurice; Kashman,
Yoel.
Tulearins A, B, and C; structures and absolute configurations.
Tetrahedron Letters, 50(27), 3820-3822 (2009).
14.
Kelman, Dovi; Kashman, Yoel; Hill, Russell T.; Rosenberg, Eugene; Loya,
Yossi.
Chemical warfare in the sea: the search for antibiotics from Red Sea corals
and sponges.
Pure and Applied Chemistry, 81(6), 1113-1121 (2009).
15.
Bishara, Ashgan; Rudi, Amira; Goldberg, Israel; Aknin, Maurice; Neumann,
Drorit;
Ben-Califa, Nathalie; Kashman, Yoel.
Tausalarin C: A New Bioactive Marine Sponge-Derived Nitrogenous
Bismacrolide.
Organic Letters, 11(16), 3538-3541 (2009).
■ Organic Chemistry
Prof. Moshe Kol
Head, Department of Organic
Chemistry
Technical Staff
Dvora Reshef
Doctoral Students
Konstantin Peres
Ayellet Zelikoff
Ad Cohen
Ekaterina Sergeeva
Shimrit Gendler
Adi Yeori
Masters Students
Pavel Bassin
Konstantin Peres
Ayellet Zelikoff
Senior Research Visitor
Dr. Jacob Kopilov
Research Projects
1.
Design of Catalysts for Polymerization of alpha Olefins
2.
Design of Catalysts for Polymerization of Cyclic Esters
3.
Asymmetric Catalysis Empolying ‘Chiral-at-Metal’ Complexes.
Collaborations
1.
Prof. Israel Goldberg, Tel Aviv University.
2.
Prof. Geoffrey W. Coates, Cornell University, USA.
3.
Prof. Jerome Lacour, Geneve, Switzerland.
4.
Prof. Barbara Milani, University of Trieste, Italy.
5.
Prof. Claudio Pellecchia, University of Salerno, Italy.
Membership in Learned Societies
1.
Israel Chemical Society.
2.
American Chemical Society.
Research Grants
2005-2009
Israel Science Foundation: Early Transition Metal Complexes of
Amine-Phenolate Ligands: Polymerization and Asymmetric Catalysis
2005-2009
United States – Israel Binational Science Foundation:
Polymerization of Lactide and Related Monomers by Metal
Complexes of Amine-Phenolate Ligands
2005-2008
Ministry of Science – Tashtiot: Nanosized Materials as Novel
Catalysts
Abstracts of Talks and Posters in Conferences
1.
M. Kol, A. Yeori, S. Segal, S. Gendler, A. Cohen, J. Kopilov, and I. Goldberg
Design of New [ODDO]-type Ligands for Group IV Metals: Coordination
Chemistry and Catalytic Applications
INVITED LECTURE.
The 73rd Annual Meeting of the Israel Chemical Society, S15-122 (2008).
Jerusalem, Israel.
2.
A. Zelikoff, K. Peres, S. Gendler, J. Kopilov, I. Goldberg, and M. Kol
Titanium and Zirconium Complexes of New Salophan Ligands: Synthesis and
Polymerization Catalysis
The 73rd Annual Meeting of the Israel Chemical Society, PA-229 (2008).
Jerusalem, Israel.
3.
A. Cohen, A. Yeori, J. Kopilov, I. Goldberg, and M. Kol
New Salan Ligands Leading to C1-Symmetric Complexes of Group IV Metals:
Synthesis and Catalytic Studies
The 73rd Annual Meeting of the Israel Chemical Society, PA-229 (2008).
Jerusalem, Israel.
4.
M. Kol, A. Yeori, S. Gendler, A. Cohen, K. Peres, J. Kopilov, and I. Goldberg
Design of New Tetradentate Bis(phenolate) Ligands: Coordination Chemistry
and Catalytic Applications
INVITED LECTURE.
International Conference on Organometallic Chemistry, Rennes, France, July,
2008.
5.
M. Kol, A. Yeori, S. Gendler, A. Cohen, A. L. Zelikoff. K. Peres, J. Kopilov, and
I. Goldberg
New Catalysts for Polymerization
INVITED LECTURE.
3rd International Forum on Homogeneous Catalysis, Shanghai, China,
September, 2008.
6.
E. Sergeeva, J. Kopilov, I. Goldberg, and M. Kol
Salan Ligands Assembled around Chiral Bipyrrolidine: Predetermination of
Chirality around Octahedral Titanium and Zirconium Centers
FIGIPAS 10, Meeting in Inorganic Chemistry, Palermo, July 2009.
7.
A. L. Zelikoff, J. Kopilov, I. Goldberg, and M. Kol
Titanium and Zirconium Complexes of Phenylene Diamine Bis(phenolate) in
Heterotactic Polymerization of rac-Lactide: A New Facet of an Old
Ligand.
FIGIPAS 10, Meeting in Inorganic Chemistry, Palermo, July 2009.
8.
A. L. Zelikoff, J. Kopilov, I. Goldberg, and M. Kol
Titanium and Zirconium Complexes of Phenylene Diamine Bis(phenolate) in
Heterotactic Polymerization of rac-Lactide: A New Facet of an Old
Ligand
International Symposium on Polymers for Advanced Technologies (PAT2009),
Jerusalem, October 2009
Publications
1.
S. Segal, A. Yeori, M. Shuster, Y. Rosenberg, and M. Kol,
Isospecific Polymerization of Vinylcyclohexane by Zirconium Complexes of
Salan Ligands.
Macromolecules 41, 1612 – 1617 (2008).
2.
S. Gendler, A. L. Zelikoff, J. Kopilov, I. Goldberg, and M. Kol,
Titanium and Zirconium Complexes of Robust Salophan Ligands
Coordination Chemistry and Olefin Polymerization Catalysis.
J. Am. Chem. Soc. 130, 2144 – 2145 (2008).
3.
A. Cohen, A. Yeori, J. Kopilov, I. Goldberg, and M. Kol,
Construction of C 1 -Symmetric Zirconium complexes by designing of New
Salan Ligands. Coordination Chemistry and Preliminary Polymerization
Catalysis Studies.
Chem. Commun. 2149 – 2151 (2008).
4.
A. Cohen, J. Kopilov, I. Goldberg, and M. Kol,
C 1 -Symmetric Zirconium Complexes of [ONNO’]-type Salan Ligands:
Accurate Control of Catalyst Activity, Isospecificity, and Molecular Weight in
1-Hexene Polymerization .
Organometallics 28, 1391 – 1405 (2009).
5.
E. Sergeeva, J. Kopilov, I. Goldberg, and M. Kol,
Salan Ligands Assembled Around Chiral Bipyrrolidine: Predetermination of
Chirality around Octahedral Ti and Zr Centres.
Chem. Commun. 3053 – 3055 (2009).
6.
E. Sergeeva, J. Kopilov, I. Goldberg, and M. Kol,
2,2’-Bipyrrolidine vs 1,2-Diaminocyclohexane as Chiral Cores for Helically
Wrapping Diamine-Diolate Ligands.
Inorg. Chem. 48, 8075 – 8077 (2009).
7.
A. L. Zelikoff, J. Kopilov, I. Goldberg, G. W. Coates, and M. Kol,
New Facets of an Old Ligand: Titanium and Zirconium Complexes of
Phenylenediamine Bis(phenolate) in Lactide Polymerisation Catalysis.
Chem. Commun. 6804 – 6806 (2009).
8.
A. Cohen, J. Kopilov, M. Lamberti, V. Venditto, and M. Kol,
Same Ligand, Different Metals: Diiodo-Salan Complexes of the Group 4 Triad
in Isospecific Polymerization of 1-Hexene and Propylene.
(Submitted).
9.
A. L. Zelikoff, J. Kopilov, I. Goldberg, and M. Kol,
Bis(aniline-phenolate) Complexes of Group 4 Metals: Coordination Chemistry
and Lactide Polymerisation Catalysis.
(In preparation).
■ Organic Chemistry
Prof. (Emeritus) Edward M. Kosower
Research Associate
Galina Borz
Dr. Natalya Eremkov
Research Projects
1.
Thin Film Spectroscopy (Surface Enhanced InfraRed spectroscopy on AgX
planar fibers);
2.
nPi* transitions of the Second Kind
Collaborations
1.
Prof. Abraham Katzir, School of Physics.
2.
Prof. Gil Markovich, School of Chemistry
3.
Prof. Nechama S.Kosower, School of Medicine.
4.
Prof. Robert C. Fahey, Chemistry, Univ. Calif.San Diego.
Editorial Boards
1.
Israel Journal of Chemistry.
Membership in Learned Societies
1.
American Chemical Society
2.
American Association for the Advancement of Science (Fellow)
3.
Society for Neuroscience
4.
Royal Society of Chemistry
5.
Israel Chemical Society
6.
American Society for Biochemistry and Molecular Biology
7.
Biophysical Society
8.
Materials Research Society
Lectures
1.
Dept. Chemistry, Univ.Calif., San Diego San Diego, Calif. April 9, 2009
2.
Dept. Chemistry, Stony Brook Univ, Stony Brook, NY April 24, 2009
Abstracts and Posters in Conferences
1.
Gordon Conference: Conference: Oxidative Stress & Disease, Il Ciocco, Italy
March 8-13, 2009.
2.
Kispoc: 12th Int’l. Symposium on Physical Organic Chemistry, Fukuoka,
Japan, Dec. 15-18, 2009.
Research Grants
1.
ISF Converging Technologies 2007-2010
2.
University Grant 2008-2009
Publications
1.
Lieberman,I., Shemer, G., Fried,T., Kosower, E.M., Markovich, G., Angew.
“Plasmon Resonance Enhanced Absorption and Circular Dichroism”.
Chem.Int’l Edn, 47, 4855-4857 (2008).
2.
Kosower, E.M.,Markovich, G., Borz, G.
“N-Methylformamide, a Hyperplectic Model for Peptides in Thin Film Infrared
Spectroscopy on Planar AgX”.
J. Phys. Chem. B, 113, 5622-5632 (2009).
■ Organic Chemistry
Prof. Moshe Portnoy
Postdoctoral Fellow
Rotem Erez
Doctoral Students
Tzofit Kehat
Lital Tuchman-Shukron
Kerem Goren
Masters Students
Keren Menda
Liat Spasser
Geny Karabline
Research Projects
The research interest of the group includes the fields of organic synthesis on solid
support (a.k.a. solid-phase synthesis or SPS), catalysis and dendrimer chemistry.
Specifically, we are interested in the development and optimization of organic
transformations that can be used for efficient SPS.
The SPS field, although
enormously expanded over the last decade and a half, still suffers from a lack of
general, efficient synthetic methodologies for many transformations.
Methods
routinely used in orthodox solution synthesis require frequent optimization/alteration
when applied to SPS. Sometimes, new techniques, specific to SPS, have to be
developed. For instance, we demonstrated in the past new SPS procedures for
aminolysis of esters and chemoselective oxazoline ring closure.
One group of compounds that we are preparing, using SPS techniques, is ligands for
organometallic
ArBr
MeO2C
(dba)
CO, NR2
Pd
PPh2
Ph2P
MeO2C
catalysts.
ArCONR2
Ar
ArCH
Bu3Sn
NH
Et
Bu
(H2O)Cl2Rh
N Cu(OTf)
O
O
O
O
CR
Ar'HN
t
Among other ligands that we
Bu
Et
Ar
phosphorous and nitrogen ligands.
N
N
HO
schemes have been developed for
the on-resin assembly of chelating
N
N
Numerous synthetic
CR
O
O
ArCHO
NAr'
HC
t
supported
Ph2P
H
NHPh
Ar
Pd(OAc)2
CHAr
H
prepared
ArCHO
CO2Me
CO2Me
aminophosphines,
O
O
α-
are
β-
and
bis(oxazoline)
ligands and a series of pincer tridentate ligands, including chiral pincer ligands.
These
ligands
were
amidocarbonylation
involved
reactions
in
supported
catalysis
(β-aminodiphosphines),
of
the
base-free
Heck
and
Knoevenagel
condensation (α-aminophosphines), enantioselective allylation of aldehydes and
hydroalkynylation of imines (oxazoline pincer ligands).
A new group of supported catalysts, being explored in our group, consists of small
metal-free organic molecules termed organocatalysts.
We are developing SPS
routes to and investigate organocatalytic processes with bifunctional catalysts (e.g.
proline derivatives, amino-ureas, -carbamates and -
Ph
O
guanidines), N-heterocyclic carbene and imidazole
catalysts. For instance, we prepared a series of
polymer-bound
chiral
amino-urea
catalysts,
O
O
Ar
NO2
+
R2
R
H
N
R
NH
Ph
NH2
O
1
R3
of
ketones
and
aldehydes
with
extraordinary
efficiency
and
enantioselectivity. Moreover, these catalysts showed very promissing results in some
domino reactions, such as Robinson annulation.
OH
HO
OH
SPS is also applied in our group for the preparation of dendritic
OH
OH
HO
templates on polymeric supports leading to dendron-functionalized
OH
O
resin beads and nanoparticles.
OH
We developed unique synthetic
schemes for the divergent synthesis of five new types of dendrons on
O
OH
O
HO
OH
HO
OH
OH
OH
OH
solid support and additional routes towards other dendritic systems on
polymers are being explored. We also mapped routes for other
multivalent oligomers on solid support, such as brush-like linear
oligomers and dendronized oligomers.
Ar
R2
R3
NO2
up to 99% yield
up to 99% ee
R1, R2, R3 = H, Alkyl
incorporating an amino acid spacer, which are capable of promoting nitro-Michael
addition
O
R1
The dendronized supports, prepared using the
aforementioned
technique,
are
converted
into
supported dendritic catalysts and the dendritic effect
on the catalytic performance is being investigated.
Thus, we demonstrated dramatic improvement in the
catalytic performance in the Pauson-Khand, Heck
and Suzuki reactions due to the introduction of
dendritic
templates
between
the
support
and
catalytic units. We also demonstrated a remarkable
improvement in the efficiency and enantioselectivity
of an organocatalyst proline in the aldol and Mannich
reactions, due to the introduction of dendritic spacers between the polymer core and
the catalytic units. A tremendous increase in the catalyst activity upon dendronization
of the support was recently demonstrated for polymer-bound N-alkylimidazole
catalysts in the Baylis-Hillman reaction. Our research in the field of supported
dendritic catalysis is aimed at both understanding the rationale behind the dendritic
effects as well as improvement and perfection of such systems for potential use.
OH O
Product ee
68
N
67
N
N
71
+
G1
catalyst
NH2
G1
G2
G3
COOH
OH
88
95
73
69 71
60
0
Cat =
G1
O
catalyst
O
O
16
WangG1 G2 G3
O
PhCHO
75
29
Cat
Cat
64 65
52
40
Yield
No reaction
NH
20
HN
HOOC
Parent resin
%
O
NH
82
80
O
cat. 30%
+
OH
N
N
N
O
29
G0
CHO
O
O
cat. 30%
100
80
60
% 40
20
0
OMe
OMe
CHO
O
+
Cat
WangG1 G2 G3
de
WangG1 G2 G3
ee
Cat
Cat
OH
O
Ph
80%
N
N
In an entirely different field of organic chemistry, we successfully collaborate with Dr.
Irit Gil-Ad and Prof. Abraham Weizman of Felsenstein Medical Research Center
targeting new psychotropic and anticancer drug candidates.
Collaborations
1.
Prof. Scott J. Miller, Yale University, USA.
O
O
HN
NH
2.
Dr. Irit Gilad, Prof. Avi Weizman, Felsenstein Medical Research Center, School of
Medicine, Tel Aviv University, Israel.
3.
Prof. Stefan Mecking, Department of Chemistry, Konstanz University, Germany.
Membership in Learned Societies
1.
Israel Chemical Society (ICS)
2.
American Chemical Society (ACS)
Research Grants
2006-2010
Israel Science Foundation/ Israel Academy of Sciences and
Humanities
2009-2013
US-Israel Binational Science Foundation (with Prof. Scott J. Miller)
Additional Professional Activities
2008-2009
Guest Editor, Israel Journal of Chemistry (with Prof. Doron Shabat)
Publications
Articles
1.
A. Mansour, T. Kehat and M. Portnoy,
Dendritic effects in catalysis by Pd complexes of bidentate phosphines on
dendronized support: Heck vs. carbonylation reactions.
Org. Biomol. Chem, 6, 3382-3387 (2008).
2.
K. Goren, T. Kehat and M. Portnoy,
Elucidation of architectural requirements from a spacer in supported proline-based
catalysts of enantioselective aldol reaction.
Adv. Synth. Catal, 351, 59-65 (2009).
3.
L. Tuchman-Shukron, T. Kehat and M. Portnoy,
Cyclic 2:1 and 1:2 aldehyde-to-acetone byproduct adducts in aldol reaction
promoted by supported proline-incorporated catalysts.
Eur. J. Org. Chem, 992-996 (2009).
4.
L. Tuchman-Shukron and M. Portnoy,
Polymer-supported highly enantioselective catalyst for nitro-Michael addition:
tuning through variation of the number of H-bond donors and spacer length.
Adv. Synth. Catal, 351, 541-546 (2009).
5.
M. Portnoy and D. Shabat,
Dendrimers and related compounds: foreword.
Isr. J. Chem. 49, III-IV (2009).
6.
K. Goren and M. Portnoy,
Supported N-alkylimidazole-decorated dendrons as heterogeneous catalysts for
the Baylis-Hillman reaction.
Chem. Commun. In press.
■ Organic Chemistry
Prof. Shlomo Rozen
Josef Kryss Chair in Organic Chemistry
Doctoral Students
Mira Carmeli Weissberg
Or Cohen
Tal Harel
Youlia Hagooly
Neta Shefer
Julia Gatenyo
Master Student
Shay Potash
Research Projects
The starting point of our work is almost always elemental fluorine. However, the work
affects many areas of synthetic and mechanistic organic chemistry which have
nothing to do with this element. Thus, we gave a new meaning to electrophilic
substitution at saturated centers - a branch of chemistry which was almost nonexisting. A “by product” of this study was the activation of “impossible” sites in
organic molecules a subject actively pursued today also by many organometallic
chemists. The general reaction of R 3 CH + F 2 forming R 3 CF proceeds with a full
R
R
R
R
R
R
retention of configuration providing one of the strongest experimental support for the
three center two electron non-classical carbocation hypothesis for which, in part,
Prof. Olah received his Nobel prize.
Reagents which our group developed from F 2 , and especially acetyl hypofluorite,
R
R
gave a strong boost to the medically important Positron Emitting Tomography (PET),
a technique used today in most major medical centers around the world. AcO18F,
whose synthesis is
based on the synthesis developed in Tel Aviv, was for a long period an essential tool
in brain and imaging research.
Our research team devised new and efficient ways for constructing the very
important CF 2 group as well as adding the equally important CF 3 one to aliphatic
compounds in many desirable important sites. New ways have been devised also for
construction of the biologically important α difluoromethyl acids, fluoroamines,
acylfluorides, fluoroacrilates, terminal difluoro olefins to mention just a few.
Fluorine is also an unique synthetic tool for general organic chemistry leading
eventually to fluorine free products. As for example, it allows syntheses of nitro
compounds, including families that could not be made before, “impossible” epoxides,
important NO derivatives which could have been made in the past at the best in very
low yields, episulfones impossible to make before and even [all]-polythiophenes- S,Sdioxides, a family of compounds which are very important in electronic and “nano”
chemistry and which despite numerous attempts eluded chemists for years.
Some of the reactions were performed by two unique classes of reagents: the
HOF•CH 3 CN complex and alkyl hypofluorites both made directly from fluorine. The
first is the most powerful oxygen transfer agent known to organic chemistry, while the
second includes the synthesis of the smallest unknown organic molecule at the time MeOF, which was believed to be impossible to make. It can serve as a source for the
unprecedented methoxylium ion “MeO+”. Apart from the obvious huge potential this
molecule has, it can serve as an unique vehicle for introducing the positron emitting
11
C isotope (half life of 20 min) into many biologically interesting compounds for PET
use.
The methods and reagents which we developed have been recognized world-wide
and described numerous times in advanced series as well as in text books. Parts of
our work have also been described many times in C&E News, Chemtech and TIME
magazine. The result of this recognition was expressed, among other ways, in
receiving the ACS and ICS awards for creativity in Organic Chemistry.
Scientific Comittees
1.
Member of the permanent Steering Committee for the European and
International Fluorine Symposia.
2.
International advisory board of the Journal of Fluorine Chemistry.
3.
Member of the Board of Directors of “HEMDA” – Tel Aviv Scientific Education
Center.
Membership in Learned Societies
1.
Israel Chemical Society.
2.
American Chemical Society.
Awards
1994
"TEVA FOUNDERS" Award.
1999
Incumbent of the Josef Kryss Chair in Organic Chemistry
2005
The American Chemical Society Award for Creative Work in
Fluorine Chemistry.
2005
The Israel Chemical Society Award.
2008
Kolthof Award – Administrated by the Technion Israel.
Research Grants
2005-2009
Israel Science Foundation.
2006-2010
USA-Israel Binational Science Foundation (BSF).
Publications
1.
O. Cohen and S. Rozen,
A general route for the synthesis of β,β-difluorocarboxylic acids.
Tetrahedron 64, 5362-5364 (2008).
2.
Y. Hagooly, R. Sasson, M. J. Welch and S. Rozen,
The Preparation of Alkyl and Aryl Chlorodifluoromethyl Ethers Using BrF 3 .
Eur. J. Org. Chem, 2875-2880 (2008).
3.
Y. Hagooly and S. Rozen,
Constructing the OCF 2 O Moiety Using BrF 3 .
J. Org. Chem, 73, 6780-6783 (2008).
4.
Y. Hagooly, O. Cohen and S. Rozen,
A general route for constructing difluoromethyl ethers
Tetrahedron Lett, 50, 392-394 (2009).
5.
O. Cohen, Y. Hagooly, and S. Rozen,
Replacing the carbonyl's oxygen with the difluoromethyl group.
Tetrahedron 65, 1361-1365 (2009).
6.
J. Luria and S. Rozen,
Adding F2 to Triple Bonds.
J. Fluorine Chem, 130, 332-335 (2009).
7.
S. Rozen,
Editorial
J. Fluorine Chem, 130, 770 (2009).
8.
N. Shefer, T. Harel and S. Rozen,
Synthesis of Oxygenated Fused Oligothiophene with HOF•CH 3 CN.
J. Org. Chem, 74, 6993-6998 (2009).
9.
Y. Hagooly, J. Gatenyo, A. Hagooly and S. Rozen,
Toward the Synthesis of the Rare N-(trifluoromethyl)amides and the Novel NDifluoromethylene-N-(trifluoromethyl)amines [RN(CF 3 )CF 2 R’] using BrF 3.
J. Org. Chem, 74, 8578-8578 (2009).
10.
M.M. Oliva, S. R. Gonzàlez, J. Casado, J.T. L. Navarrete, J. S. S. Melo, S.
Rozen,
Optical Properties of [all]- S,S-Dioxide Oligothiophenes.
Portugaliae Electrochimica Acta 27, 533-537 (2009).
11.
O. Cohen, E. Mishani, and S. Rozen,
From Carboxylic Acids to the Trifluoromethyl Group using BrF 3 .
In press.
12.
T. Harel, N. Shefer, Y. Hagooly and S. Rozen,
Synthesis of diazafluorene- and diazafluorenone-N,N’-dioxides
HOF•CH 3 CN.
In Press.
using
■ Organic Chemistry
Prof. Doron Shabat
Doctoral students
Rotem Perry
Eran Sela
Naama Carton
Orit Redy
Anna Gopin
Roey Amir
Erez Rotem
Roy Weinstein
Amit Sagi
Masters students
Einat Finfer
Research Projects
During the course of our work at Tel-Aviv University, we developed novel molecular
systems with self-immolative capabilities. The ability of a molecule to undergo
spontaneuse domino-like disassembly upon a stimulus event is refered as selfimmolative feature. Intially, we develped a chemical adaptor system for targeted
prodrug approach. The prodrug is disassembled of the targeting moiety to realse the
active drug upon a triggering event. Next, we develoed dendrimers with selfimmolative capabilities and later, we extanded this approach to linear polymers and
comb polymers. Recently, we introduce a novel techinque for exponential
amplification of diagnostic signals. This technique is based on a disticntive dendritc
chain reaction (DCR) and has the potential to detect a single molecule activity.
Chemical Adaptor systems
We have developed a drug delivery system based on a chemical adaptor that
provides a generic linkage of a drug with a targeting device in a manner set to be
triggered by defined enzymatic activity (Figure 1). The system is generic and allows
using a variety of drugs, targeting devices, and enzymes by introducing the
corresponding substrate as a trigger for drug release in the chemical adaptor. The
chemical adaptor system was designed with stable chemical linkages, in order to
avoid nonspecific drug release in vivo. Proof of concept was demonstrated using
etoposide as the drug, an HPMA-copolymer as the targeting device and catalytic
antibody 38C2 as the triggering enzyme (Figure 2).
Enzyme
Substrate
Chemical
Adaptor
Targeting
Device
Drug
Enzyme
Chemical
Adaptor
Targeting
Device
Drug
Spontaneous
Chemical
Adaptor
Drug
Targeting
Device
Figure 1: General design of the chemical adaptor system. Cleavage of the enzyme
substrate generates an intermediate that spontaneously rearranges to release the
drug from the targeting device.
CH3
CH2 C
CO
X
NH
CH2
CH2OH
CH3
CH3
CH2 C
CO
NH
CH2
CO
NH
CH2
OC
x = 95 mol%
y = 5 mol%
CH3
CH2 C
CO
NH
X
CH2
CH2OH
CH3
Y
x = 95 mol%
y = 5 mol%
O
N
O
N
O
N
O
N
O
HO
Antibody 38C2
N
2
O
H3CO
O
O
OCH3
O
O
N
O
N
O
O
O
OH
OH
O
CO2
N
O
H3C
CH3
CH2 C
CO
X
NH
CH2
CH2OH
CH3
H2O
N
OCH3
O
O
O
O
CO2
O
HO
O
O
O
N
O
H3C
OH
O
N
O
H3CO
O
N
N
O
N
Y
O
O
1
CH3
CH2 C
CO
NH
CH2
CO
NH
CH2
OC
x = 95 mol%
y = 5 mol%
OH
CH3
CH2 C
CO
NH
CH2
CO
NH
CH2
OC
3
HO
O
O
H3CO
OCH3
Y
O
O
O
O
OH
O
N
N
HO
H3 C
HO
O
O
O
O
OH
Etoposide
O
O
Figure 2: Mechanism of etoposide drug release from the HPMA-copolymer, using
catalytic antibody 38C2 as the triggering enzyme.
Self-immolative dendrimers
Self-immolative dendrimers are unique structural molecules that can release all of
their tail units, through a domino-like chain fragmentation, which is initiated by a
single cleavage at the dendrimer’s core (Figure 3). Incorporation of drug molecules
as the tail units and an enzyme substrate as the trigger, can generate a multi-prodrug
unit that is activated with a single enzymatic cleavage. Dendritic prodrugs, activated
through a single catalytic reaction by a specific enzyme, were shown to present
significant advantages in the inhibition of tumor growth, especially if the targeted or
secreted enzyme exists at relatively low levels in the malignant tissue. Selfimmolative dendrimers were also applied as a general platform for biosensor
molecules, which are used to detect/amplify enzymatic activity. The development and
evaluation of self-immolative dendrimers so far, generate seventeen publications.
The concept was also highlighted in Nature and in Chemical & Engeenering News.
Figure 3: Self-immolative dendrimers, as shown in the picture, spontaneously
release all the end-group molecules following a single activation event. This
triggering event induces a cascade of self-eliminations, which leads to complete
dissociation of the dendrimer into its separate building blocks.
Self-immolative Polymers
Smart polymers are special kinds of polymeric molecules that respond to external
stimuli. We have developed a novel smart polymer designed to sequentially
disassemble into its building blocks upon initiation by a triggering event at the
polymer head (Figure 4). The polymer structure is based on a polycarbamate
backbone
that
disassembles
through
a
domino-like,
1,6-elimination
and
decarboxylation reactions. To demonstrate the concept, we synthesized a self-
immolative polymer that amplifies a single cleavage reaction into multiple-release of
fluorogenic molecules and confirmed the head to tail disassembly concept. These
polymers can be used to prepare highly sensitive molecular sensors with large
signal-to-noise ratios. The sensors should be useful for the detection of a wide range
of biological and chemical activities through use of the appropriate trigger at the
polymer-head.
T
H T
MONOMER
H
MONOMER
T
H
MONOMER
Trigger
n
Trigger cleavage
MONOMER
Trigger
(n+2)
Figure 4: Illustration of the disassembly of a self-immolative polymer.
Insertion of additional substituents at a specific position of each monomer generates
self-immolative comb-polymers with side-releasable groups that could be used as a
drug delivery system (Figure 5). Upon activation of the head group, the combpolymer undergoes complete disassembly to release multiple copies of side-reporter
group. The polymer was prepared by simple polymerization of a monomer, followed
by capping of the polymer head with a trigger. This technique allowed rapid synthesis
of the polymeric molecule containing a large number of reporter units. We
demonstrate that a water-soluble version of the comb-polymer can be activated by an
enzyme and thus has potential as a selctive drug delivery system.
T
MONOMER
H T
MONOMER
H T
MONOMER
H
Trigger
Trigger Cleavage
n
R
R
R
T
MONOMER
Trigger
H
R
n
R
n
MONOMER
Figure 5: Illustration of the disassembly of a self-immolative comb-polymer.
Chemotherapeutic Bone-Targeted Bisphosphonate Prodrugs with Hydrolytic
Mode of Activation
Our group is also developing prodrugs for selective chemotherapy ,a representative
example is described below:
Osseous tissues are considered to be limited as therapeutic target sites due to their
biological properties. We have designed and synthesized two kinds of hydrolyticallyactivated chemotherapeutic prodrugs containing bisphosphonate, a bone-targeting
moiety. The first can be conjugated to drug molecules with an available hydroxy
group; the drug is attached to the bisphosphonate component through an ester-labile
linkage. The second is for use with drug molecules with amine functional group. In
this case, a self-immolative linker is used to attach the drug to the bisphosphonate
component through a carbonate-labile linkage. The concept was demonstrated using
the drugs camptothecin, which has a hydroxy functional group, and tryptophan, which
is a model molecule for a drug with amine functionality. Both prodrugs showed
significant binding capability to hydroxyapatite, the major component of bone, and
were hydrolytically activated under physiological conditions.
Figure 6: Camdronate - A chemotherapeutic Bone-Targeted Bisphosphonate
Prodrug with Hydrolytic Mode of Activation
Dendritic Chain Reaction
Signal amplification techniques are broadly used to improve the detection sensitivity
of various analytes for diagnostic purposes. We have developed a novel, non-PCR-
based, modular technique for exponential amplification of a diagnostic signal that is
conveniently performed in water environment. The technique is based on a distinctive
dendritic chain reaction (DCR); the diagnostic signal was generated upon
disassembly of a self-immolative dendrimer that released chromogenic molecules
(Figure 7). Under ideal conditions, a single analyte molecule initiates a dendritic
chain reaction that generates a strong diagnostic signal. When coupled with a
protease diagnostic probe, the DCR technique detected the activity of penicillin-Gamidase with high sensitivity. This is the first example of exponential signal
amplification performed under aqueous conditions that is not based on PCR.
Reagent
Analyte
Trigger
Adaptor
Reporter
Reagent
Reagent
Reporter
Reagent
Signal
Figure 7: Graphical ilustration of a dendritic chain reaction.
Recent Publications
1.
Erez, R., Ebner, S., Attali, B., Shabat, D,
“Anticancer Bisphosphonate Bone-Targeted Prodrugs with Hydrolytic Mode of
Activation”.
Bioorg. Med. Chem. Lett, 18, 816-20 (2008).
2.
Sagi, A., Weinstain, R., Karton, N., Shabat, D.
“Self-Immolative Polymers” .
J. Am. Chem. Soc, 130, 5434-5 (2008).
3.
Weinstain, R., Sagi, A., Karton, N., Shabat, D.,
“Self-Immolative Comb-Polymers: Multiple-Release of Side-Reporters by a
Single Stimulus Event”.
Chem. Eur. J, 14, 6857-61 (2008).
4.
Erez, R., Shabat, D.,
“The Azaquinone-Methide Rearrangement: Comparison Study of 1, 6- and 1,
4-Eliminations under Physiological Conditions”.
Org. Biomol. Chem., 6, 2669-72 (2008).
5.
Sella, E., Shabat, D.,
“Self-Immolative Dendritic Probe for Direct Detection of Triacetone
Triperoxide”, Chem. Commun., 44, 5701-3 (2008).
6.
Miller, K., Erez, R., Segal, E., Shabat, D., Satchi-Fainaro, R.,
“A Novel Bispecific Targeting Agent Based on a Polymer-Alendronate-Taxane
Conjugate to Target Prostate Cancer Bone Metastases”.
Angew.Chem. Int. Ed. Engl., 48, 2949-54 (2008).
7.
Stern, L., Perry, R., Ofek, P., R., Many, A., Shabat, D., Satchi-Fainaro, R.
“A novel antitumor prodrug designed to be cleaved by the endoprotease
legumain”.
Bioconjug. Chem., 20, 500-10 (2009).
8.
Erez, R., Segal, E., Miller, K., Satchi-Fainaro, R., Shabat, D.,
"Enhanced Cytotoxicity of a Polymer-Drug Conjugate with Triple Payload of
Paclitaxel”.
Bioorg. Med. Chem., 17, 4327-35 (2009).
9.
Avital-Shmilovici, M., Shabat, D.,
"Enzymatic Activation of Hydrophobic Self-Immolative Dendrimers:The Effect
of Reporters with Ionizable Functional Groups”.
Bioorg. Med. Chem. Lett., 19, 3959-62 (2009).
10.
Sella, E., Shabat, D.,
“Dendritic Chain Reaction”.
J. Am. Chem. Soc., 131, 9934-6 (2009).
11.
Weinstein, R., Baran, S. P., Shabat, D.,
“Activity-Linked Labelling of Enzymes by Self-Immolative Polymers”.
Bioconjug. Chem., 20, 1783–1791 (2009).
12.
Perry-Feigenbaum, R., Baran, S. P., Shabat, D.,
“The Pyridinone-Methide Elimination”.
Org. Biomol. Chem., In press (2009).
13.
Weinstain, R., Segal, E., Satchi-Fainaro, R., Shabat, D.,
“Real-Time Monitoring of Drug Release.
In Press.
14.
Avital-Shmilovici, M., Shabat, D.,
“Self-Immolative
Dendrimers:A
Amplification”,
In Press.
Distinctive
Approach
to
Molecular
Book Chapters
1.
Erez, R., Shabat, D., Book edited by Steven Rokita, Reactive Intermediates in
Chemistry and Biology entitled Quinone Methides: “Self-Immolative
Dendrimers Based on Quinone Methides”. Wiley-VCH, 2009, pp. 121-163.
2.
Weinstain, R., Shabat, D., Book edited by Raz Jelinek, Cellular and
Biomolecular
Recognition:
"Catalytic
Antibodies
for
Selective
Chemotherapy". Wiley-VCH, 2009 pp. 111-136.
Patents Applications
1.
Satchi-Fainaro, R., Miler, K., Shabat, D.,Erez, R., “A Nobel bi-Specific
Targeting Agent Based on a Polymer-Alendronate-Taxene Conjugate to
Target Metastatic Prostate Carcinomas”, International Provisional Patent,
2008.
2.
Shabat, D., Sella, E., Gazit, E. “Dendritic Chain Reaction”, International
Provisional Patent, 2008.
■ Organic Chemistry
Prof. Arkadi Vigalok
Doctoral Students
Shlomi Elias
Ariela Kaspi
Anette Yahav
Natalia Kotzen
Nelly Shapiro
Anat Molad
Masters Students
Mili Abramov
Adam Sharf
Ina Dubinsky
Tal Sela
Research Projects
1. Transition metal – mediated formation of carbon-halogen bonds, with
emphasis on C-F bond forming chemistry.
In this project, we developed an “electrophilic fluorination” access to organometallic
(palladium and platinum) fluoro complexes. We showed that some of these
complexes, previously believed to be too unstable, can be isolated and their reactivity
further elucidated. We also found the conditions under which aromatic halides can be
selectively formed via the reductive elimination mechanism. A particularly interesting
finding
was
that
such
reaction
can
compete
favorably
with
the
more
thermodynamically preferred formation of carbon-carbon bond. Another important
take-home-message from our work is that the reductive elimination reaction can
occur in parallel with the oxidation addition reaction, even before the final neutral
products are formed. Hence, the reductive elimination of a carbon-halogen bond can
be achieved by maintaining the proper geometry of the high-valent neutral metal
complex or short-lived cationic intermediate. Our group is presently one of the world’s
leaders in metal-mediated formation of carbon-halogen bonds.
2. Synthesis and application of calixarene compounds as ligands in metalmediated transformations.
In this project, we obtained a general understanding of how organometallic
calixarene inclusion complexes can be selectively formed. Thus, their formation can
now be predicted. We demonstrated that some of these complexes can be catalysts
in organic reactions with the catalysis proceeding via a single-site bimetallic
mechanism. This was the first unambiguous example of such a mechanism operating
in a zinc system and, considering importance of bimetallic zinc complexes in living
systems, should influence our views on Zn-mediated transformations in biology as
well as synthetic chemistry. More recently, we reported the first example of a
calixarene-based system that employs partially oxygen-depleted calixarene moieties
as ligands. Our system showed superior catalytic activity when compared with the
unmodified calixarene system. We are currently exploring our original protocols
toward oxygen depleted calixarenes to further applications in catalysis and
supramolecular chemistry, including chemistry of chemosensors.
3. Green Chemistry
All biologically relevant organic reactions take place in the aqueous media. On the
other hand, very few synthetic organic transformations are performed with water as a
solvent. Considering that organic solvents often represent the major pollution
component of multi-step organic synthesis, their replacement by the environmentally
benign water can significantly reduce the amount of chemical waste in synthetic
processes. Two directions are presently pursued: use of amphiphilic block-copolymer
ligands for micellar catalysis in water and synthetic organic transformations under the
“on water” conditions. Both directions specifically address the recycling of the
reaction media, which is essential for the development of “green” synthetic
alternatives.
Current Collaborations
1.
Prof. Helmut Fischer, University of Konstanz.
2.
Prof. Andrei Vedernikov, University of Maryland.
Membership in Learned Societies
1.
Israel Chemical Society.
2.
American Chemical Society.
Research Grants
2007 – 2008
Kurt Lion Foundation, Oxidative Fluorination of Metal-Carbon
Multiple Bonds.
2007 – 2011
US – Israel Binational Science Foundation, C-X Reductive
Elimination from Soluble Pt(IV) Complexes in Organic and
Aqueous Media.
2008 – 2009
Horowitz Foundation, 2-in-1 Preparation of Diols and
Carboxylic
2008 – 2012
Acids “On Water”.
Israel Science Foundation, Oxygen-Depleted Calix[4]arenes for
Catalytic and Sensory Applications
Most of organic compounds are insoluble in water. Normally,
it would be a significant problem requiring the use of harmful
organic solvents.
We can turn it into a strength to make some organic reactions
faster and more selective. Just stir the insoluble organic
compounds with water and watch the reaction…
O
R
H
R
Aldehyde
OH
Carboxylic Acid
C-
O
N+
+
2
R
O
Air and Water
Ambient temperature R
H
R1
100% Atomy economy
R
O
Air and Water
H
N
O
O
Formed "on water"
OH
R1
+
R
H
N
R1
O
Formed "in water"
Publications
1.
Kaspi. A, A. Yahav-Levi, I. Goldberg, A. Vigalok,
Xenon Difluoride Induced Aryl – Iodide Reductive Elimination: a Simple
Access to Difluoro Pd(II) Complexes.
Inorg. Chem, 47, 5-8 (2008).
2.
A. Yahav-Levi, I. Goldberg, A. Vigalok, A. N. Vedernikov,
Competitive Aryl-Iodide vs. Aryl-Aryl Reductive Elimination Reactions In
Pt(IV) Complexes: Experimental and Theoretical Studies.
J. Am. Chem. Soc, 130, 724-731 (2008).
3.
N. Kotzen, A. Vigalok,
The Inside of Metal Calixarene Chemistry.
J. Supramol. Chem. (special issue), 20, 129-139 (2008).
N. Shapiro, A. Vigalok,
Highly Efficient Organic Reactions “in Water”, “on Water” and Both.
Angew. Chem. Int. Ed, 47, 2849-2852 (2008).
Selected as a “Hot Paper” by the Editorial Board. Highlighted in Globes and
Jerusalem Post (8.4.2008). Selected for “Faculty of 1000 Biology”
(http://www.f1000biology.com/article/id/1108522).
4.
5.
A. Vigalok,
Metal Mediated Formation of Carbon-Halogen Bonds, Invited Concept Article.
Chem. Eur. J, 14, 5102 – 5108 (2008).
6.
N. Kotzen, I. Goldberg, A. Vigalok,
Stepwise Boron-to-Zinc C 6 F 5 Group Transfer in a Zn-Calixarene System.
Organometallics, 28, 929–932 (2009).
7.
E. Tzadka, I. Goldberg, A. Vigalok,
Entry to New N,O-Ligands from Oxygen-Depleted Calixarenes.
Chem. Commun, 2041-2043 (2009).
8.
S. Elias, A. Vigalok,
Amphiphilic Block Polypeptide-Type Ligands for Micellar Catalysis in Water.
Adv. Syn. Catal, 351, 1499-1504 (2009).
Highlighted in SYNFACTS, October 2009.
9.
N. Shapiro,M. Kramer,I. Goldberg, A. Vigalok,
Straightforward Radical Organic Chemistry in Neat and “on Water”.
Green Chemistry ,in press.
■ Physical Chemistry and Electrochemistry
Prof. (Emeritus) Kedma Bar-Eli
Research Projects
1. Formation of bubbles is gs evolution oscillators and the use of delay differential
equations for treating these problems.
2. Periodic perturbation applied to kinetic oscillating chemical models.
3. Coupling of chemical oscillators by diffusion.
4. Earth temperature with delay equations.
5. Cellular automath applied to electrochemistry.
■ Physical Chemistry and Electrochemistry
Prof. (Emeritus) Emilia Kirowa-Eisner
Research Projects
Electrode Kinetics
• Analysis of underpotential deposition of metals on a foreign substrate (with Prof.E.
Gileadi)
Environmental Study
• Effect of road run-off on the water quality and biological systems (with Prof. U.
Shanas)
Collaborations
1.
Professor E. Gileadi, School of Chemistry, Tel Aviv University
2.
Professor U. Shanas, Department of Biology, University of Haifa
Publications
E. Kirowa-Eisner, D. Tzur and E. Gileadi.
Under Potential Dissolution of Metals under Conditions of Partial Mass-Transport Control.
J. Electroanal. Chem, 621 146 (2008) .
■ Physical Chemistry and Electrochemistry
Prof. (Emeritus) Eliezer Gileadi
Research Fellows
Prof. Vladimir Tsionsky
Dr. Olga Berkh (with Prof. Y. Shacham-Diamand, Faculty of Engineering)
Doctoral Students
Adi Naor
(with Prof. N. Eliaz, Faculty of Engineering)
Alla Douhin
(with Prof. N. Eliaz, Faculty of Engineering)
Galina Katz
Masters Students
Yigal Weinberger
(with Prof. N. Eliaz, Faculty of Engineering)
Research Projects
Physical Electrochemistry
Structure of the Interface and charge transfer across it.
Studies of the liquid-like layer at the frozen-electrolyte/metal interface.
(with Professors V. Tsionsky, M. Urbakh and L. Daikhin)
Alloy Deposition
Deposition of magnetic alloys for MEMS (with Prof. Y. Shacham-Diamand Faculty of
Engineering).
Deposition of Rhenium and its alloys, (with Prof. N. Eliaz, Faculty of Engineering).
Current Collaborations
1.
Professors E. Kirowa-Eisner, V. Tsionsky, M. Urbakh and L. Daikhin, School of
Chemistry, Tel-Aviv University.
2.
Prof. N. Eliaz, School of Engineering, Tel-Aviv University.
3.
Prof. Y. Shacham-Diamand, School of Engineering, Tel-Aviv University.
4.
Prof. B. MacDougall, National Research Council of Canada, ICPET, Ottawa.
5.
Prof. I. Reiss, Faculty of Physics, Technion, Haifa.
6.
Visiting Professor and Associate Member of the Center for Electrochemical
Science and Engineering, Department of Materials Science, the University
of Virginia, Charlottesville, Virginia.
7.
Adjunct Professor, Department of Chemical Engineering, Case Western
Reserve University, Cleveland, Ohio.
Membership in Learned Societies
1.
The International Society of Electrochemistry (Fellow 2007).
2.
The Electrochemical Society (Fellow 1997).
3.
The American Association for the Advancement of Science AAAS (Fellow 1998).
4.
The Israel Chemical Society.
Awards and Honors
1997
Fellow of the Electrochemical Society.
1998
Fellow of the American Association for the Advancement of Science (2003).
2003
The Olin Palladium Award of the Electrochemical Society.
2004
The Herzberg Memorial Prize and Fellowship of the National Research
Council of Canada.
2005
Fellow of the Royal Society of Canada (FRSC) and of its Academy of
Sciences.
2007
Fellow of the International Society of Electrochemistry (ISE).
2008 The Henry B. Linford Award of the Electrochemical Society, for excellence
in teaching.
Research Grants
2005-2009
Israel Academy of Sciences: Studies of the liquid-like layer between
ice or a frozen electrolyte and metal surfaces, employing the
EQCM. (with Prof. V. Tsionsky).
Publications
1.
E. Kirowa-Eisner, D. Tzur and E. Gileadi,
UPD Dissolution of Metals under Conditions of Partial MassTransport Control,
J. Electroanal. Chem. 621 ,146 (2008).
2.
O. Berkh, Yu. Rosenberg, Y. Shacham-Diamand, E. Gileadi,
Electrodeposition of near Equiatomic Thick Films.
Electrochem. and Solid-State Lett. 11, (4), D38(2008).
3.
O. Berkh, Y. Shacham-Diamand, E. Gileadi,
Stability of the Electrodeposition Process for CoPt Alloy Formation.
J. Appl. Electrochem., 38 ,1275 (2008).
4.
E. Gileadi,
Charge and Mass Transfer in Metal Deposition and Dissolution.
Israel J. Chem., 48 ,121 (2008).
5.
O. Berkh, Y. Shacham-Diamand E. Gileadi,
Reduction of Ammonium Ion on Pt Electrodes,
J. Electrochem.Soc. 155, (10), F ,223 (2008).
6.
O. Berkh, Y. Shacham-Diamand E. Gileadi,
Process of CoPt Alloy Electrodeposition for MEMS/NEMS Applications.
ECS Transactions-Honolulu, HI vol. 13. (2009), in press.
7.
A. Naor, N. Eliaz and E. Gileadi,
Electrodeposition of Re-Nickel Alloys from Aqueous Solutions.
Electrochim. Acta, 54 6028 (2009).
8.
E. Gileadi, O. Berkh, Y. Shacham-Diamand,
Time Effects in the Electrodeposition of CoPt Magnetic Alloys.
Electrochem. and Solid-State Lett., 12 (8) d53-d56 (2009).
9.
A. Naor, N Eliaz and E. Gileadi,
Electrodeposition of Alloys of Re with Iron-Group Metals from Aqueous Solutions.
ECS Transactions, Vienna October (2009), in press.
4T
Book Chapters
1.
M. Urbakh, V. Tsionsky E. Gileadi, and L. Daikhin, Probing the Solid/Liquid
Interface with the Quartz-Crystal Microbalance, Springer Ser., Chem.
Sensors and Biosensors, pp. 113-149, Vol. 5 Series Ed. O. S. Wolfbeis, Vol.
Eds. C. Steinem and A. Jonshoff, Berlin (2007).
2.
N. Eliaz and E. Gileadi, Induced Codeposition of W, Mo and Re with
Transition Metals, in Modern Aspects of Electrochemistry, Eds: C. G.
Vayenas and R. E.. White, Vol. 42 pp. 191-301, Kluver Publ. (2008).
■ Physical Chemistry and Electrochemistry
Prof. Israel Goldberg
Alexander and Klara Stransky Chair in the Chemistry of Advanced Materials
Technical Staff
Zafra Stein
Post-Doctoral Fellows
Dr. Rajesh Koner
Dr. Anirban Karmakar
Doctoral Students
Sophia Lipstman
Masters Students
Leonid Kozlov
Hatem Titi
Research Projects
1.
Crystal Engineering of Nanoporous Solids, MOFs and Surface MOFs:
We are
exploring ways to construct, by noncovalent supramolecular synthesis, new nanoporous
molecular solids based on organic building blocks with structural and functional similarity to
the inorganic zeolites, as well as to ellucidate their unique properties. This includes metalorganic-framework (MOF) materials in the bulk, as well as on surface supports.
2.
Supramolecular Chirality: The tailored induction of supramolecular chirality in non-
covalent assemblies without resorting to chiral reagents is investigated, as such
supramolecular materials may be useful in the processes of enantioselective synthesis,
separation and catalysis, and the fabrication of polar devices.
3.
Supramolecular Design of Multiporphyrin Domains. Nano-materials and Bulk Solids
(with Prof. M. C. Drain): Porphyrin-based supramolecular architectures have numerous
applications as biomimetic models or as functional materials for the transport of energy,
charge, molecules and ions. We are exploiting the concepts of supramolecular selfassembly of suitably functionalized porphyrins to predictably form spatially defined
nanostructures as well as extended coordination polymers of these chromophores.
Deposition of the supramolecular assemblies on surfaces is another aspect of these studies.
4.
Structure and Properties of Corroles (with Prof. Z. Gross): Corroles are macrocycles
related to both hemes (porphyrins) and Vitamin B12 (corrin). They share with corrine an
identical ring skeleton and with porphyrins their aromaticity.
We study the structural
chemistry of these compounds and of their metal complexes (e.g., with Fe, Rh, Ga, Co, Mn,
Cu, Zn, etc.) in order to provide the essential information for understanding and improving
the properties of these materials in catalysis and biophysical applications.
5.
Structural Chemistry of Organometallic Catalysts (with Prof. M. Kol):
The catalytic properties of organometallic complexes of various phenolate-ligands are
related to their structure.
6.
Structural Chemistry of Organometallic Compounds (with Dr. A. Vigaluk):
The project focuses on the characterization of new halogeno complexes of palladium and
platinum, and of calixarene-based metal inclusion complexes with catalytic properties.
7.
Structural Chemistry of Ruthenium Catalysts (with Dr. N. G. Lemcoff):
Studies of structure-properties relationships in sulphur and nitrogen chelated ruthenium
catalysts for olefin metathesis.
Current Collaborations
1.
Prof. Michael C. Drain, Hunter College, City University of New York.
2.
Prof. Dr. Roland Fischer, Ruhr-University-Bochum.
3.
Prof. Zeev Gross, Technion, Haifa.
4.
Prof. Gabriel Lemcoff, Ben-Gurion University of the Negev, Beer-Sheba.
5.
Prof. M. Kol, Prof. A. Vigaluk, Prof. Y. Kashman, Tel Aviv University.
Scientific Committees
1.
Scientific Committee of the International Symposia Series on Supramolecular
Chemistry.
Editorial Boards
1.
Editorial Board, Journal of Inclusion Phenomena and Macrocyclic Chemistry.
Membership in Learned Societies
1.
American Crystallographic Association
2.
European Crystallographic Association
3.
Society of Porphyrins and Phthalocyanines
4.
Israel Chemical Society
5.
Israel Crystallographic Society
Research Grants
2004-2008
The Israel Science Foundation.
“Supramolecular Chemistry of Porphyrinoids in Solids, and Engineering
of Functional Structures”
2004-2009
COST – European Cooperation of Scientific and Technical Research.
"Molecular Tectonics Approach of Porous Crystalline Materials"
COST Action D31.
2008-2012
The Israel Science Foundation.
“Supramolecular Design of Framework Solids and Chiral Assemblies”
Presentations at International Conferences
1.
I. Goldberg, S. George, S. Lipstman and S. Muniappan
Porphyrin Assemblies: Rational Design of Coordination Networks and Supramolecular
Chirality.
Presented at the Fifth International Conference on Porphyrins and Phthalocyanines,
ICPP-5, 6-11 July, 2008, Moscow, Russia.
2.
I. Goldberg
Porphyrin Assemblies; Rational Design of Coordination Networks ans Supramolecular
Chirality.
Presented at the 4th International Symposium on Macrocyclic and Supramolecular
Chemistry,
21-25 June 2009, Maastricht, The Netherlands.
S. Lipstman, S. Muniappan and I. Goldberg
P
3.
P
Supramolecular Reactivity and Chirality in Mixed meso-(Pyridyl)/(Iodophenyl)Porphyrins
Presented at FIGIPAS 10th, the 10th International Meeting in Inorganic Chemistry,
1-4 July 2009, Palermo, Italy.
4.
I. Goldberg
Designer Porphyrin Assemblies.
Presented at the 25th European Crystallographic Meeting, 16-21 August 2009,
Istanbul, Turkey.
Publications
Articles
1.
A. Kaspi, A. Yahav-Levi, I. Goldberg and A. Vigaluk,
Xenon Difluoride Induced Aryl Iodide Reductive Elimination:
a Simple Access to Difluoropalladium(II) Complexes
Inorg. Chem., 47, 5-7 (2008).
2.
A. Yahav-Levi, I. Goldberg, A. Vigaluk and A. N. Vedernikov,
Competitive Aryl-Iodide vs Aryl-Aryl Reductive Elimination Reactions in Pt(IV)
Complexes: Experimental and Theoretical Studies.
J. Am. Chem. Soc., 130, 724-731 (2008).
3.
L. Kozlov, J. M. Rubin-Preminger and I. Goldberg,
Remarkable π-π Stacking of Dipyrido[f,h]quinoxaline-6,7-dicarbonitrile in Its Ethanol
Solvate.
Acta Cryst., C64, o1-o3 (2008).
4.
S. Lipstman and I. Goldberg,
Supramolecular Hydrogen Bonding of [5,10,15,20-Tetrakis (4-carboxyphenyl)
porphyrinato] Palladium(II) in the Presence of Competing Solvents.
Acta Cryst., C64, m53-m57 (2008).
5.
A. Falber, L. Todaro, I. Goldberg, M. V. Favilla and C. M. Drain,
Routes to New Hafnium(IV) Tetraaryl Porphyrins and Crystal Structures of
Unusual Phosphate, Sulfate, and Peroxide-Bridged Dimers
Inorg. Chem., 47, 454-467 (2008).
6.
J. M. Rubin-Preminger, L. Kozlov and I. Goldberg,
Hydrogen Bonding and π-π Stacking Interactions in Aquachloridobis(1,10phenathroline)-cobalt(II) Chloride Dichloridobis(1,10-phenathroline)cobalt(II)
Hexahydrate.
Acta Cryst., C64, m83-m86 (2008).
7.
L. Kozlov and I. Goldberg,
Supramolecular Interaction Patterns in the Zinc(II) Dichloride and Tin(IV)
Tetrachloride Complexes with Dipyrido[f,h]quinoxaline-6,7-dicarbonitrile.
Acta Cryst., C64, m123-m126 (2008).
8.
S. Gendler, A. Zelikoff, J. Kopilov, I. Goldberg and M. Kol,
Titanium and Zirconium Complexes of Robust Salophan Ligands. Coordination
Chemistry and Olefin Polymerization Catalysis.
J. Am. Chem. Soc., 130, 2144-2145 (2008).
9.
S. Muniappan, S. Lipstman and I. Goldberg,
Borylated Porphyrins: 5,10,15,20-Tetrakis
(5,5-dimethyl[1,3,2]dioxaborinan-2-yl) porphyrin
Nitrobenzene Disolvate.
Acta Cryst., C64, o177-o179 (2008).
10.
A. Ben-Asuly, E. Tzur, C. E. Diesendruck, M. Sigalov, I. Goldberg and N. G. Lemcoff,
A Thermally Switchable Latent Ruthenium Olefin Metathesis Catalyst.
Organometallics, 27, 811-813 (2008).
11.
S. Muniappan, S. Lipstman and I. Goldberg,
Rational Design of Supramolecular Chirality in Porphyrin Assemblies.
The Halogen Bond Case.
Chem. Commun., 1777-1779 (2008).
12.
S. Gendler, J. Kopilov, I. Goldberg and M. Kol,
Construction of C 1 -Symmetric Zirconium Complexes by the Design of New Salan
Ligands.
Coordination Chemistry and Preliminary Polymerisation Catalysis Studies.
Chem. Commun., 2149-2151 (2008).
13.
I. Goldberg,
Crystal Engineering of Nanoporous Architectures and Chiral Porphyrin Assemblies.
CrystEngComm, 10, 637-645 (2008).
14.
S. Lipstman, S. Muniappan and I. Goldberg,
Supramolecular Reactivity of Porphyrins with Mixed Iodophenyl and Pyridyl mesoSubstituents.
Cryst. Growth Des., 8, 1682-1688 (2008).
15.
T. Kost, M. Sigalov, I. Goldberg, A. Ben-Asuly and N. G. Lemcoff,
Latent Sulfur Chelated Ruthenium Catalysts: Steric Acceleration Effects on Olefin
Metathesis.
J. Organomet. Chem., 693, 2200-2203 (2008).
16.
R. Koner and I. Goldberg,
The First Coordination Polymer of Lanthanum(III) with a Naphthalene-1,4,5,8tetracarboxylic 1,8-Anhydrate Derivative.
Acta Cryst., C64, m264-m266 (2008).
17.
E. Tzur, A. Ben-Asuly, C. E. Diesendruck, I. Goldberg and N. G. Lemcoff,
Homodinuclear Ruthenium Catalysts for Dimer Ring-Closing Metathesis.
Angew. Chem. Int. Ed., 47, 6422-6425 (2008).
18.
L. Kozlov and I. Goldberg,
Hydrogen-bonding versus π-π Stacking Interactions in Dipyrido[f,h]quinoxaline-6,7dicarbonitrile and 6,7-Dicyanodipyrido[f,h]quinoxaline-1-ium chloride dihydrate.
Acta Cryst., C64, o498-o501 (2008).
19.
S. Lipstman and I. Goldberg,
2D and 3D Coordination Networks of Tetra(carboxyphenyl)porphyrins with Cerium
and Thulium Ions.
J. Mol. Struct., 890, 101-106 (2008).
20.
S. Lipstman and I. Goldberg,
Hydrogen-Bonded Assemblies of 5,10,15,20-Tetrakis(4-hydroxyphenyl)porphyrin with
Dimethylformamide, Dimethylacetamide and Water.
Acta Cryst., C65, o3-o7 (2009).
21.
R. Koner and I. Goldberg,
Probing the Supramolecular Interaction Synthons of 1-Benzofuran-2,3-Dicarboxylic
Acid in its Mono-Anionic Form.
Acta Cryst., C65, m37-m41 (2009).
22.
L. Goren, D. Pappo, I. Goldberg and Y. Kashman,
Acyclic and Cyclic Thioenamino Peptides: Solution and Solid Phase Synthesis.
Tetrahedron Lett., 50, 1048-1050 (2009).
23.
N. Kotzen, I.Goldberg and A. Vigalok,
Stepwise Boron-to-Zinc C 6 F 5 Group Transfer in a Zn-Calixarene System.
Organometallics, 28, 929-932 (2009).
24.
R. Koner and I. Goldberg,
Supramolecular Reactivity of Naphthalene-1,4,5,8-Tetracarboxylic Acid Towards
Transition Metal Ions: Coordination Polymers and Discrete Complexes with CuII, NiII
and CoII.
CrystEngComm, 11, 367-374 (2009).
25.
R. Koner and I. Goldberg,
Square-Grid
Coordination
Networks
of
Diaquabis(4,4'-bipyridyl)copper(II)
Crosslinked by Hydrogen Bonds Through Two Monoanions of 1-Benzofuran-2,3dicarboxylic Acid and Five Molecules of Water.
Acta Cryst., C65, m62-m65 (2009).
26.
R. Koner and I. Goldberg,
Square-Grid Coordination Networks of (5,10,15,20-Tetra-4pyridylporphyrinato)zinc(II) in its Clathrate with Two Guest Molecules of 1,2Dichlorobenzene:Supramolecular Isomerism of the Porphyrin Self-Assembly.
Acta Cryst., C65, m139-m142 (2009).
27.
R. Koner and I. Goldberg,
Unique Two-Dimensional Coordination Network of 1-Benzofuran-2,3-dicarboxylate
with Lanthanum(III) by Solvothermal Synthesis.
Acta Cryst., C65, m149-m151 (2009).
28.
A. Cohen, J. Kopilov, I. Goldberg and M. Kol,
C 1 -Symmetric Zirconium Complexes of [ONNO']-type Salan Ligands: Accurate
Control of Catalytic Activity, Isospecificity and Molecular Weight in 1-Hexene
Polymerization
Organometallics, 28, 1391-1405 (2009).
29.
H. Soreq, A. Rudi, I. Goldberg, M. Aknin and Y, Kashman,
Saldedines A and B, Dibromo Proaporphine Alkaloids from a Madagascan Tunicate.
J. Nat. Prod., 72, 784-786 (2009).
30.
R. Koner and I. Goldberg,
Two- and Three-Dimensional Hydrated Coordination Polymers of Diaqualanthanum
(3+) Ions with 2-Hydroxypropanedioate, Oxalate and Acetate Anions as Bridging
Ligands.
Acta Cryst., C65, m160-m164 (2009).
31.
R. Koner and I. Goldberg,
The Coordination Polymers Poly[μ-4,4'-bipyridyl-di-μ-formato-copper(II)] and catenaPoly[[[diaqua(1-benzofuran-2,3-dicarboxylato)copper(II)]-μ-1,2-di-4-pyridylethane]
dihydrate].
Acta Cryst., C65, m185-m189 (2009).
32.
E. Tzadka (Bukhaltsev), I. Goldberg and A. Vigalok,
Entry to New N,O-Ligands from Oxygen-Depleted Calixarenes.
Chem. Commun., 2041-2043 (2009).
33.
E. Sergeeva, J. Kopilov, I. Goldberg and M. Kol,
Salan Ligands Assembled Around Chiral Bipyrrolidine: Predetermination of Chirality
Around Octahedral Ti and Zr Centres.
Chem. Commun., 3053-3055 (2009).
34.
A. Bishara, A. Rudi, I. Goldberg, M. Aknin and Y. Kashman,
Tulearins A, B, and C: Structures and Absolute Configurations.
Tetrahedron Lett., 50, 3820-3822 (2009).
35.
R. Koner and I. Goldberg,
Crystal Engineering of Molecular Networks. Hydrogen Bonding Driven TwoDimensional Assemblies of Tetrapyridylporphyrin with Benzene Tri- and TetraCarboxylic Acids.
CrystEngComm, 11, 1217-1219 (2009).
36.
S. Lipstman and I. Goldberg,
Unsolvated 5,10,15,20-Tetrakis(4-pyridyl)porphyrin, Its Sesquihydrate, and Its 2Chlorophenol Disolvate. Conformational Versatility of the Ligand.
Acta Cryst., C65, o447-o452 (2009).
37.
A. Ben-Asuly, A. Aharoni, C. E. Diesendruck, Y. Vidavsky, I. Goldberg, B. Straub and
N. G. Lemcoff,
Photoactivation of Ruthenium Olefin Metathesis Initiators.
Organomet. Chem., 28, 4652-4655 (2009).
38.
A. Bishara, A. Rudi, I. Goldberg, M. Aknin, D. Neumann, N. Ben-Califa and Y.
Kashman,
Tausalarin C; A New Bioactive Marine Sponge-Derived Nitrogeneous Bismacrolide.
Org. Lett., 11, 3538-3541 (2009).
39.
S. Lipstman and I. Goldberg,
Hydrogen-Bonded Three Dimensional Network of Lanthanum(III) Exocyclic Complex
with 5,10,15,20-Tetra-4-pyridylporphyrin.
Acta Cryst., C65, m371-m373 (2009).
40.
E. Sergeeva, J. Kopilov, I. Goldberg and M. Kol,
2,2'-Bipyrrolidine versus 1,2-Diaminocyclohexane as Chiral Cores for Helically
Wrapping Diamine-Diolate Ligands.
Inorg. Chem., 48, 8075-8077 (2009).
41.
I. Goldberg,
Coulombic Interactions, Hydrogen Bonding and Supramolecular Chirality in
Pyridinium
Trifluoromethanesulphonate.
Acta Cryst., C65, o509-o511 (2009).
42.
A. L. Zelikoff, J. Kopilov, I. Goldberg, G. W. Coates and M. Kol,
New Facets of an Old Ligand. Titanium and Zirconium Complexes of
Phenylenediamine Bis(phenolate) in Lactide Polymerization Catalysis.
Chem. Commun., 6804-6806 (2009).
43.
C. E. Diesendruck, E. Tzur, A. Ben-Asuly, I. Goldberg, N. G. Lemcoff and B. F.
Straub,
Predicting the Cis-Trans Dichloro Configuration of Group 15-16 Chelated Ruthenium
Olefin Metathesis Complexes: A DFT and Experimental Study.
Inorg. Chem., 48, 10819-10825 (2009).
44.
S. Lipstman and I. Goldberg,
Versatile Supramolecular Reactivity of Zinc-tetra(4-pyridyl)porphyrin in Crystalline
Solids.
Polymeric Grids with Zinc Dichloride and Hydrogen Bonded Networks with Mellitic
Acid.
Beilstein J. Org. Chem., 5, No. 77, (2009).
■ Physical Chemistry and Electrochemistry
Dr. Amir Goldburt
Technical Staff
Dr. Uzi Eliav
Doctoral student
Omry Morag
Masters Students
Anat Haimovitch
Bosmat Shifman
Gili Abramov
Hadar Ivanir
Research Grants
2008-2012 ISF: Israel Science Foundation.
2008-2012 IRG: Marie Curie International Re-integration Grant.
Research Interests
In recent years there has been a significant progress in the ability to use the technique of
magic-angle spinning (MAS) solid-state NMR to solve structures, and to look at the
dynamics of complex biological systems such as proteins, amyloids, enzymes, membrane
proteins and even intact viruses.
Our research group aims at the development and applications of novel magic-angle spinning
solid-state NMR techniques to complex bio-macromolecules. For this purpose we have
purchased a new 600MHz wide-bore, triple-resonance NMR spectrometer. Currently ongoing projects in the group are the following:
-
NMR
characterization
of
filamentous
bacteriophage
viruses:
Filamentous
bacteriophages are long slender virions, which consist of a circular single stranded DNA
wrapped by some thousands of copies of a single coat protein (See Figure). A few copies
of additional proteins exist at both ends, the role of which is to help in the intrusion and
the assembly processes. The phages are used in a variety of fields of science such as
molecular biology, peptide phage display, phage therapy and as templates in
nanotechnology. All these developments have been possible due to the ease of gene
manipulation of the phage DNA.
Despite significant efforts in elucidating their structure, there are still many features that are
unknown or differ in the different models.
Currently in our group we study four different strains of bacteriophages – fd, M13, Ike, and
I22. A typical 13C-13C spectrum of the fd bacteriophage appears in the figure above.
-
Psychiatric drug targets: Lithium (in the form of lithium salts) has been used as a
mood stabilizer for over 50 years now, and is still being prescribed to numerous patients
experiencing bipolar disorder (manic depression), despite its long-term adverse effects.
Among several identified targets, lithium inhibits inositol monophosphatase (IMPase), an
enzyme that hydrolyses myo-inositol monophosphate to inositol and inorganic phosphate.
Depletion of inositol levels has been suggested as a mechanism for the therapeutic effects
of lithium and therefore significant effort has been dedicated for understanding the
mechanism of inhibition. Despite many years of research, the exact binding mode of lithium
to its target is still not entirely known; lithium is almost completely ‘silent’ to X-ray
crystallography measurements, mainly due to its low electron density. Conversely, lithium is
a highly sensitive NMR nucleus, and it was shown to bind IMPase by solution NMR,
although the actual binding site was not established, and whether there are any additional
sites is still unknown. In our group we managed to over-express an purify an active form of
SuhB inositol monophosphatase (A bacterial monophosphatase), and currently direct lithium
measurements are underway.
New labeling strategies: One of the problems of NMR is spectral congestion,
especially when systems of homogeneous secondary structure are involved (e.g.
helical membrane proteins or phages). Since MAS NMR uses primarily 13C and 15N
detection methods, our team develops new strategies to produce alternative sparse
enrichment schemes thereby reducing the total amount of 13C enriched atoms, and
consequently lessening spectral overlap.
-
Protein structure and dynamics: How good are we (the
solid-state NMR community) at solving structures? Do we have a
precise protocol and the know-how to solve three-dimensional
structures in the same way this is done in X-ray crystallography
and solution NMR? Up to this date, a handful of structures have
The known structure of
the B1 domain of
Protein L (X-ray)
been solved by MAS NMR and deposited in the PDB (Protein
Data Bank).
However, at the same time, MAS NMR aims at more and more complex
systems such as amyloids, membrane proteins etc. In our group we choose a model protein
system (The B1 domain of protein L) on which we test and improve current techniques for
three-dimensional structure elucidation by magic-angle spinning NMR.
-
Methods for the detection and correlation of quadrupolar spins:
The periodic table consists of many atoms with nuclear spins larger than one-half
(quadrupolar), yet many of them have low gyromagnetic ratios and small natural abundance.
Therefore, their detection sensitivity may be very low. Examples are Na, Mg, Ca, Li and
more. Enzyme metal centers almost always include atoms with quadrupolar spins. Also,
many nanoparticles and other hybrid materials contain metals of non-integer quadrupolar
spins. In our group we develop and analyze methods to increase the detection sensitivity of
quadrupolar nuclei; we also develop schemes that correlate quadrupolar spins with the more
abundant spin-1/2 nuclei such as 1H, 13C and 15N.
Publications
1.
A. Goldbourt,
Magic-angle spinning solid state NMR: application to structural biology, In:
Encyclopedia of analytical chemistry (2009), biomolecules analysis, Jonh Wiley &
Sons Ltd.
2.
S. Reich, G. Leitus, R. Popovitz-Biro, A. Goldbourt, and S. Vega,
A possible 2D H xWO 3 superconductor with a Tc of 120 K, J. Supercond.
Nov. Magn. 22, 343-346 (2009).
■ Physical Chemistry and Electrochemistry
Prof. (Emeritus) Gil Navon
Technical Staff
Dr. Uzi Eliav
Post Doctoral Fellows
Dr. Wen Ling
Dr. Inbar Elron-Gross
Doctoral Students
Galit Saar
Tal Ben David
Yoni Herzberg
Masters Students
Michal Rivlin
Yana Solominsky
Research Projects
Biomedical Applications of NMR and MRI
1.
NMR and MRI methods for the study of connective tissues (cartilage, tendon and
intervertebral disc).
2.
Spectroscopic MRI of nerves
3.
Combination of MRI and focused ultrasound
4.
New MRI contrast mechanisms with application for following thermal destruction of
tumors.
5.
Cross correlation effects between paramagnetic and quadrupolar interactions.
6.
Chemical exchange reactions in aqueous formaldehyde solutions.
Scientific Committees
1.
Member of the Council, International Society of Magnetic Resonance (ISMAR)
2.
Executive Board, European Magnetic Resonance (EUROMAR)
3.
International Advisory Board, International Conference of Magnetic Resonance in
Biological Systems (ICMRBS) 2008, San Diego.
4.
Co-Chairman, Bat Sheva Seminar on Frontiers of Biomedical Magnetic Resonance,
Safed. 2009.
Collaborations
1.
Prof. Alexej Jerschow, New York University
2.
Prof. Ravinder Regatte, New York University Medical School
3.
Prof. Lucio Frydman, The Weizmann Institute of Science
4.
Prof. Dan Gazit, Hadassah Medical School
Research Grants
2007-11 The Israel Academy of Sciences and Humanities (ISF)
2007-11
European Union PF7
2008-12
U.S.-Israel Binational Science Foundation (BSF)
2009-12
Israel Ministry of Sience & Technology "Tashtiot"
Awards
Fellow of the International Society of Magnetic Resonance, 2008
Publications
1.
W. Ling, R. R. Regatte, G. Navon, and A. Jerschow,
Assessment of Glycosaminoglycan Concentration in Vivo by Chemical ExchangeDependent Saturation Transfer (gagCEST).
Proc.Natl. Acad. Sci. USA, 105, 2266-2270 (2008).
2.
D. Carasso, A. Hanannel and G. Navon,
A New MRI Method, Demonstrated in vivo for the Assessment of Focused
Ultrasound Thermal Coagulation.
NMR Biomed, 21, 637-643 (2008).
3.
Harel, U. Eliav S. Akselrod and G. Navon,
Magnetization Transfer Based Contrast for Imaging Denatured Collagen. J. Magn.
Reson. Imag, 27, 1155-1163 (2008).
4.
W. Ling, U. Eliav, G. Navon, A. Jerschow,
Chemical Exchange Saturation Transfer by Intermolecular Double Quantum
Coherence,
J. Magn. Reson. 194, 29-32 (2008).
5.
D. Ben Bashat, I. Sivan, M. Sigal, O. Eizenstein, P. Pianka, R. Malach, M. Graif, T.
Hendler and G. Navon,
T1 Weighted Functional Imaging Based on Contrast Agent in Pre-Surgical Mapping,
J. Magn. Reson. Imag, 28, 1245-1250 (2008).
6.
W. Ling, R. R. Regatte, M. Schweitzer, G. Navon, and A. Jerschow,
Glycosaminoglycan Chemical Exchange-Dependent Saturation Transfer – A Novel
Non-Invasive Magnetic Resonance Imaging Strategy.
US Musculoskeletal Review, 3, 13-16 (2008).
7.
U. Eliav, C. Naumann, G. Navon and P.W. Kuchel,
Double quantum transitions as the origin of the central dip in the z-spectrum of 2H 2 O
in variably stretched gel,
J. Magn. Reson., 198, 197-203 (2009).
8.
R. B. van Heeswijk, K. Uffmann, A. Comment, F. Kurdzesau, C. Perazzolo, C.
Cudalbu, S. Jannin, J. A. Konter, P. Hautle, B. van den Brandt, G. Navon, J. J. van
der Klink and R. Gruetter.
Towards using hyperpolarized Lithium-6 as a sensor of contrast agent in vivo.
Magn. Reson. Med., 61, 1489–1493 (2009).
9.
M. Mishkovsky, U. Eliav, G. Navon, L. Frydman, Nearly 106–fold enhancements in
intermolecular 1H double-quantum NMR experiments by nuclear hyperpolarization.
J. Magn. Reson., 200,142-146 (2009).
10.
G. Saar, Y. Zilberman, H. Shinar, K. Keinan-Adamsky, G. Pelled, D. Gazit, G. Navon,
Monitoring of the Effect of Intervertebral Disc Nucleus Pulposus Ablation by MRI.
NMR Biomed. In Press (Early view Febuary 2010).
11.
K. Keinan-Adamsky, H. Shinar, S. Shabat, Y. S. Brin, M. Nyska, G. Navon, 23Na and
H Magnetic Resonance Studies of Osteoarthritic and Osteoporotic Articular
Cartilage.
Magn. Reson. Med., Accepted for publication.
2
12.
Y. Hertzberg, A. Volovick. Y.Zur, Y. Medan, S. Vitek and G. Navon,
Ultrasound Focusing Using Magnetic Resonance Acoustic Radiation Force Imaging:
Application to Ultrasound Transcranial Therapy.
Med. Phys., Accepted for publication.
Patents
1. A. Pines, T.F. Budinger, G. Navon, Y Song, S. Appelt, A. Bifone, R.E. Taylor, B.M.
Goodson, R. Seydoux, T. Room, T. Pietrass, Apparatus for Preparing a Solution of a
Hyperpolarized Noble Gas for NMR and MRI Analysis, U.S. Patent No.: 7,385,395
(2008).
2. U. Eliav, G. Navon, A. Neufeld, Method of Selective Excitation for Improving Contrast in
Magnetic Resonance Imaging, U.S. Patent No. 7,390,671 (2008).
3. A. Neufeld, M. Levine, G. Navon, Radiofrequency Magnetic Field Resonator and a
Method of Designing the Same. U.S. Patent No. 7,573,270 B2 (2009).
■ Physical Chemistry and Electrochemistry
Prof. Fernando Patolsky
Research Associates
Dr. Boris Filanovsky
Dr. Ruben Tirosh
Dr . Eran Granot
Post-Doctoral Fellows
Dr. Nava Shpaisman
Dr. Maya Bar
Dr. Koteeswara Reddy
Dr. Devika Reddy
Technical Staff
Dora Tsur
Doctoral Students
Yoni Engel
Moshit Ben-Ishai
Moria Kwiat
Uri Givan
Roey Elnatan
Hagit Peretz
Alexander Pevzner
Michael Ioffe
Masters Students
Guy Davidi
Tamir Ducobni
Ra'aya Kantaev
Rawi Dirawi
Research Projects
‘‘Nanoscale science holds extraordinary promises to impact the crucial issues of our era, such
as improved medical diagnosis and treatment, renewable energy, more efficient information
technology, and environmental protection.’ Thus, my research interests are broadly concerned
with the ‘multifunctional’ systems of reduced dimensionality, and their applications for
addressing important chemical, biochemical, physical and technological problems. Specifically,
we are interested in the synthesis, fundamental physical and chemical properties, and
applications of integrated nanostructured materials that combine tunable optical, electrical and
magnetic properties. These materials include inorganic alloys and compounds, as well as
inorganic-organic, and inorganic-biomolecule composites. Particular attention is devoted to the
mutual interactions between light, electricity, and magnetism at the nanometer scale. The
rational design and studies of these systems will provide important fundamental understanding
of the relationship between electronic and crystal structures of the low-dimensional
multifunctional systems and their optical, electrical and magnetic properties. A major goal of my
research program is to address the structure-function relationship, as one of the most basic
questions in physical-inorganic and materials chemistry. To that end, a variety of synthetic,
structural, spectroscopic, magnetic, and transport techniques are applied, with an emphasis on
single nanostructure measurements. A second and more central aspect of my research
concentrates on the application of such developed nanomaterial-based electronic devices in the
biological and chemical detection area, with the aim to explore and exploit the nano-scale
potential advantages in answering ‘open questions’ in biology. Finally, in order to achieve the
goals of the research plan we combine the use of advanced nano- and micro-fabrication
techniques, a broad range of microscopic and macroscopic surface characterization
techniques, electrochemical and electroanalytical techniques (ac- and dc modes, and fieldeffect transistors detection), single-molecule optical detection techniques, advanced
approaches for the synthesis of nanoscale materials and their characterization and our
personal unique approach for the delicate and effective combination of biomaterials and living
cells with inorganic/organic/metallic substrates in the creation of novel and exciting bio-artificial
systems
Some of our recent achievements in these areas are:
1. The high-fidelity large-scale assembly of nanowire and nanotube elements, with
controlled and uniform orientation and density at spatially well-defined locations on
substrates, presents one of the most significant bottleneck challenges facing their
integration in real-world electronic applications. Enormous efforts have been focused on
tackling the challenge of controlled assembly, and while significant progress has been
achieved, it still remains an unresolved obstacle. Thus, a great need exists to develop new
strategies that will overcome the limitations of current approaches, before 1D nanomaterials
can play an important role as building blocks for real-world applications.
Our group has developed the universal ‘knocking-down’ approach, based on the controlled
in-place planarization of nanowire elements, for the formation of large-scale ordered
nanowire arrays. The controlled planarization of the nanowires is achieved by the use of an
appropriate elastomer-covered rigid-roller device. After being knocked down, each nanowire
in the array can be easily addressed electrically, by a simple single photolithographic step,
to yield a large number of nanoelectrical devices with an unprecedented high-fidelity rate.
The approach allows controlling, in only two simple steps, all possible array parameters:
nanowire dimensions, chemical composition, orientation and density. The resulting
“knocked-down” arrays can be further used for the creation of massive nanoelectronicdevice arrays. More than million, 1.000.000, devices were already fabricated with yields
over 98% !!!!, on substrate areas of up, but not limited to, to 10cm2.
I believe that this powerful breakthrough strategy, by virtue of its simplicity and accuracy,
has the potential to revolutionize the fabrication of nanoelectronic systems and to enable a
wide range of technological applications.
2.My group has developed, for the first time, controllable and reproducible synthetic routes
to prepare robust single-crystalline Si nanotubes of nearly any size/inner diameter, ranging
from only 1.5 nm!!!! to more than 500 nm, controllable wall thickness, variable shapes
(various nanotubular to conical structures of controlled tapering angles) and finely tuned
chemical composition, to form p/n-type Si nanotubes and SiGe alloy nanotubes. The rational
control over the chemical composition opens up the opportunity to achieve high quality
electronic materials and to tune their properties to better suit various applications. The
systematic variation in the shape of the Si nanotubes in our study is reproducible, and as a
result we are able to controllably tune not only the diameter, wall thickness and composition
but also the geometry of the Si nanotubes, from wire-shape to conical and 'funnel' shape,
where all the structures are single crystalline.
In addition, our current research expands into the functionalization of the resultant
nanotubes, which is a crucial step to many future applications including separations
(selective filtering), selective transport and sensing of chemical and biological molecules.
The integration of the nanotubular building blocks into electrical devices is of critical
importance for most required applications. Thus, we have fabricated FET devices from our
p-doped Si nanotubes, and carried out electrical transport measurement to evaluate their
performance.
Combined together, these strategies have greatly expanded the scope of control over critical
parameters of the nanotubes, and thus suggest that our synthesized Si nanotubular
structures are ideal candidates for various biological and chemical applications and
nanoscale device applications.
We can envision the development of nanofluidic electrical devices, nanofluidic sensing
devices, nano-molecular counters, molecular separators and molecular concentrator
devices. Also, opto-electrical future nanodevices will be developed based on this novel
family of nanotubular silicon structures.
3. Nanoarchitectonics can be classified into two fields, "NanoSystem Organization" and
"NanoMaterials Creation". A typical example of the "NanoMaterials Creation" is synthesis of
new materials that do not exist in nature and show interesting new functions.
"Nanoarchitectonics" is critical for development of nanotechnology, beyond the stage of
nanoscience.
We
are
confident
that
this
submitted
manuscript
exemplifies
‘Nanoarchitectonics’ at its best; the synthesis of novel materials with functions and
properties not achievable by the use of existent nanostructures.
Our group demonstrated, for the first time, the synthesis of a novel generation of siliconbased hybrid nanotubular materials; ”tube-in-tube” and ”wire-in-tube” nanostructures. We
demonstrate the ability to prepare multi-walled nanotubular structures, for which the
dimensions, including the interwall distance and chemical composition of each wall can be
individually controlled. Finally, by exploiting the individual electrical addressability of each
wall, we show the potential of the hybrid nanotubes obtained to serve as future building
blocks for the fabrication of multifunctional electrical devices, unachievable by the use of
current known nanostructures. This is the first demonstration on the preparation of
multiwalled nanotubular structures with the capability to individually control the properties of
each single wall. Also, the potential to electrically address each wall opens the possibility to
use these novel nanostructures as building blocks in the fabrication of complex
nanoelectrical devices.
More specifically, we have successfully synthesized two unique crystalline hybrid
nanotubular structures. (1) The first consists of entirely-hollow, uniform and well-separated
tube-in-tube structures (DW/MWSiNT-like structures) with variable and uniform interwall
distances ranging from 2 to 60nm !!!!. In addition, the walls of these nanotubular structures
can be readily and differentially doped in situ with different dopants to form nanotubular
structures with multiple built-in electrical properties. Another significant achievement of this
work is the formation of Si/Ge core-multishell heterostructures which were used as a
template for our hybrid nanotubular structures. In this regard, this is the first experimental
proof for the formation of smooth and uniform Ge shells on both Si cores and Ge(core)Si(shell) structures, in a layer-by-layer mode, with no limiting dimensions. (2) In addition, we
have demonstrated for the first time the synthesis of wire-in-tube nanostructures. The
nanostructures can be formed with different controlled Si core diameters and with variable
distance between the SiNW core and the SiNT walls.
These unique nanotubular structures might open the opportunity to fabricate novel
nanoscale electrical and optoelectrical devices, as exemplified in this work by the fabrication
of novel FETs devices of dual electrical performance. These findings might also open up the
possibility to fabricate new nanoscale devices of higher complexity based on this new family
of intriguing building blocks.
4. Considerable attention and ongoing concern has been drawn towards countering terrorist
threats and the presence of trace contamination of explosives in soil and ground water, for
which improved methods are required to facilitate their detection. Our lab has developed, for
the first time, the use of silicon-nanowire electrical noses arrays as an effective platform
exhibiting unprecedented outstanding detection capability for TNT and other explosive
species. We make use of electron-rich amino-silane monolayer-functionalized SiNW devices
for the label-free, multiplexed real-time and rapid supersensitive electrical detection of TNT,
down to the ~100 attomolar detection limit (~1x10-6 ppt). The electron-rich amine-monolayer
associated with the SiNW device surface binds the electron-defficient explosive molecules
(e.g. TNT) through charge-transfer donor-acceptor interactions leading to charged TNTamine complexes in intimate vicinity to the nanowire surface, which cause stiff changes on
the conductance of the nanoelectrical sensing elements. This, in turn, results in an
unprecedented detection sensitivity limit of TNT in water solutions, as well as TNT vapors
sampled directly from air. Finally, we envision a mass deployment of sensors stationed
discreetly on every street corner sampling the surrounding air with the highest sensitivity, all
connected by a network to an analysis center. Please note that these sensor arrays
developed in our lab are being widely implemented in chemical sensing set-ups and medical
diagnosis systems.
5. My lab has developed a new generation of highly effective environmentally-clean fuel
cells based on the use of non-noble metal catalysts. These fuel cells are not only more
energetically effective than their noble-metal catalyzed counterparts, but are orders of
magnitude cheaper. In addition, our catalysts do not suffer from the poisoning limitations
well known to noble-metal catalysts. Our lab, in collaboration with investing partners, has
developed a prototype for powering portable electronics for long periods of time without any
recharging being required. A number of important patents were submitted, and collaboration
with large corporations in this area of research. This invention is currently on its way to
further development and commercialization.
6. “Ultra-Dense Heteroepitaxial Si-ZnO Hierarchical Nanostructures: Towards Future
Photovoltaic Devices”.
Nanomaterials such as nanoparticles (NPs), nanowires (NWs), nanobelts (NBs), nanotubes
(NTs) and nanorods (NRs) have emerged as attractive building blocks for the development
of future electronic and optoelectronic devices. The fact that these structures are tunable
and reproducible in a predictable manner during their synthesis, broadens their application
to various fields. In the bottom-up approach, single- and multi-branched, encapsulated (co-
axial or radial), and axial homo- or heteronanostructures are three typical architectures
having numerous applications due to their complexity-dependent properties.
In recent years, branched nanostructures, particularly hierarchical and/or hyper-branched
structures have received more attention because of their rich architectures and promising
applications in the fields of optoelectronics and photovoltaics. This type of hierarchical
structure exhibits a large surface area that also enhances their functionality. However, the
methods applied to synthesize these hierarchical heteronanostructures have poor control
over the composition, structure and density of the second-generation shell branches.
My group have demonstrated a simple approach to the synthesis of highly-ordered, highly
dense and well-controlled hierarchical silicon core (Si)-zinc oxide (ZnO) branched
heteronanostructures, showing remarkable heteroepitaxial characteristics, in spite of the
very large lattice mismatch between these materials (~15%).
Notably and additionally, by using the same experimental route, the current methodology
allows for the synthesis of ZnO nanoparticles-decorated SiNWs and Si-ZnO conformal coreshell nanowire heterostructures. The Si/ZnO heteronanostructures pave the way for the
integration of a wide-bandgap oxide semiconductor with traditional silicon semiconductor
devices. Also, these structures can be considered as potential candidates for the
development of a new generation of solar-cell devices. In contrast to known reported
branched nanostructures, where the nanowire backbone is uncovered in areas where
branches are absent, our heteronanostructures present silicon cores uniformly covered with
ZnO. Thus, the creation of individual electrical contact to each component of the
heterostructure can be easily and effectively achieved. This is a critical issue in the future
development of relevant devices. The hierarchical heterostructured solar cells would be able
to use a larger portion of the solar spectrum than do traditional homostructured cells.
Furthermore, we have shown preliminary results on the well-controlled growth of verticallyaligned ZnONR-decorated SiNWs in large-wafer-scale arrays with a view to fabrication of
future optoelectronic and photovoltaic devices.
Publications
1.
R. Elnathan, R. Kantaev and F. Patolsky,
Synthesis of Hybrid Multicomponent Disklike Nanoparticles.
NanoLetters, 8, 3964-3972 (2008).
2.
M. Devika, N.K. Reddy, F. Patolsky, K. Gunasekhar,
Ohmic contacts to SnS films: Selection and estimation of thermal stability.
J. Appl. Physics, 104, 124503 (2008).
3.
Moshit Ben Ishai and Fernando Patolsky,
Shape and Dimension-Controlled Single-Crystalline Silicon and SiGe Nanotubes:
Towards NanoFluidic FET Devices.
J .Am .Chem. Soc., 131, 3679–3689 (2009).
4.
Uri Givan and Fernando Patolsky,
Pressure-Modulated Alloy Composition in Si (1-x) Ge x Nanowires.
NanoLetters, 9, 1775–1779 (2009).
5.
Moshit Ben Ishai and Fernando Patolsky,
Tube-in-Tube and Wire-in-Tube NanoBuilding Blocks: Towards the Realization of
Multifunctional Nanoelectronic Devices.
Angew. Chem. Int. Ed., 46, 8699-8702, Accepted as Hot Paper (2009).
6.
Devika M, Reddy NK, Ramesh K, Patolsky F, Gunasekhar KR
Weak rectifying behaviour of p-SnS/n-ITO heterojunctions.
Solid State Electronics, 53, 630-634 (2009).
7.
M. Devika, N. K. Reddy, F. Patolsky, K. Ramesh, K. R. Gunasekhar Temperature.
dependent structural properties of nanocrystalline SnS structures.
Applied Physics Letters, 95, 261907-1-261907-3, (2009).
8.
Nicholas A. Kotov, Jessica O. Winter, Isaac P. Clements, Edward Jan, Brian P.
Timko, Stéphane Campidelli, Smita Pathak, Andrea Mazzatenta, Charles M.
Lieber, Maurizio Prato, Ravi V. Bellamkonda, Gabriel A. Silva, Nadine Wong Shi
Kam, Fernando Patolsky, Laura Ballerini
Nanomaterials for Neural Interfaces.
Advanced Materials, Vol. 21, Issue 40, 3970-4004 (2009).
9.
Uri Givan and Fernando Patolsky,
Doping Influence on Si (1-x) Ge x Nanowires Chemical Composition, Morphology, and
Electrical Properties.
Journal of Physical Chemistry C, Accepted for publication (2010).
10.
M. Devika, N. Koteeswara Reddy, Alexander Pevzner and Fernando Patolsky,
Ultra-Dense Heteroepitaxial Si-ZnO Hierarchical Nanostructures: Towards Future
Photovoltaic Devices.
ChemPhysChem, Accepted for publication (2010).
11.
Moshit Ben Ishai and Fernando Patolsky
A New Synthetic Approach of High-Quality Crystalline Coaxial Core-Multishell
Ge@SiGeSi and Si@GeSi Nanowire Heterostructures.
Advanced Materials, Accepted for publication (2010).
12.
Alexander Pevzner, Yoni Engel, Roey Elnathan, Tamir Ducobni, Moshit Ben-Ishai,
Koteeswara Reddy, Nava Shpaisman, Alexander Tsukernik, Mark Oksman and
Fernando Patolsky
Knocking Down Highly-Ordered Large-Scale Nanowire Arrays.
NanoLetters, Accepted for publication (2010).
13.
Moria Kwiat, Asher Peretz and Fernando Patolsky
Preparation of Highly-Ordered and Controlled Large-Scale Neuronal Networks of
Individual Cells.
Submitted for publication (2010).
14.
Yoni Engel, Roey Elnathan, Guy Davidi and Fernando Patolsky
Supersensitive Explosives Detection by NanoNose Arrays.
Submitted for publication (2010).
15.
Eran Granot, Boris Filanovsky, Rawi Dirawi and Fernando Patolsky
Nanotextured Copper Substrates as Highly Effective and Long-Lasting Fuel Cell
Anodes.
Submitted for publication (2010).
16.
M. Devika, N. Koteeswara Reddy, Alexander Pevzner, Moshit Ben-Ishai and
Fernando Patolsky
CdSe-ZnO Hierarchal heterostructures.
Submitted for publication (2010).
17.
Nava Shpaisman, Uri Givan and Fernando Patolsky
One-step Synthesis of Multi-segmented CdSe Barcode Nanowires.
ACS Nano, Submitted for publication (2010).
■ Physical Chemistry and Electrochemistry
Prof. Emanual Peled
Nathan Cummings Chair For Pure and Applied Electrochemistry
Academic Staff
Dr. Dina Golodnitsky
Research Fellows and Technical Staff
Dr. Ella Strauss
Dr. Adi Aharon
Yitzhak Lavi
Yaron Konra
Kobi Saadi
Tania Ripenbein
Vova Zel
Doctoral Students
Shaul Richman
Michal Philosoph
Nina Rudy Travitzky
Ekaterina Freedman
Raya Kovarsky
Meital Goor
Hadar Mazor
Svetlana Menkin
Roy Gorenshtain
Meital Alon
Masters Students
Roy Gorenshtain
Meital Alon
Keren Shvartsman
Dima Kaplan
Roni Hadar
Shlomo Avshalom
Research Projects
1.
Synthesis and characterization of platinum based nano catalysts for oxygen
reduction and hydrogen oxidation in fuel cells applications.
2.
Intercalation process of lithium in carbon, alloys and graphite in liquid nonaqueous solutions and polymer electrolytes.
3.
Development and characterization of thin, high aspect ratio, 1.5 to 3.5V
cathodes.
4.
Development and characterization of three dimensional on-chip lithium ion
microbattery.
5.
Study of mass and charge transport in ordered composite polymer electrolytes
and in single ion Li polymer electrolyte conductors.
6.
Development of regenerative fuel cell for solar and wind energy storage.
7.
Development and characterization of nano platinum alloy catalysts for
ethylene glycol oxidation.
8.
Development and characterization of direct methanol fuel cell (DMFC) and
direct ethylene glycol fuel cell (DEGFC) for portable and electric vehicle
applications.
9.
Development and characterization of a low cost proton conducting membrane
(PCM) and composite proton exchange membranes for high temperature
applications.
Current Collaborations
1.
Prof. S. Greenbaum, Hunter College N.Y.
2.
Prof. B. Owens, University of Southampton, United Kingdom
3.
Prof. J. Thomas, Prof. Kristina Edström, University of Uppsala
4.
Prof. P. Simon, Université Paul Sabatier Toulouse
5.
Prof. J-M. Tarascon, Prof. M. Armand, Centre National de la
Recherche Scientifique, France (CNRS)
Research Grants
2007-2011
Single ion conducting channels
BSF
2008-2009
Micro fuel cells
MAFAT
2008-2009
Advanced fuel cells
MAFAT
2008-2011
Superlion
EU
2008-2009
RFC
Enstorage
Publications
Articles
1.
H. Mazor, D. Golodnitsky, Yu. Rosenberg, E. Peled, W. Wieczorek and B. Scrosati,
Solid composite polymer electrolytes with high cation transference number;
Israel J. Chem, submitted, 4, (2008).
2.
T. Ripenbein, D. Golodnitsky, M. Nathan, E. Peled,
Porous interlaced structures for 3D-microbatteries.
Electrochimica Acta doi:10.1016/j.electacta.01.057 (2009).
3.
Nina Travitsky; Larisa Burstein; Yuri Rosenberg and Emanuel Peled,
Effect of Methanol, Ethylene Glycol and their Oxidation By-Products on the Activity of
Pt-Based Oxygen-Reduction Catalysts.
JPS, accepted 5, (2009).
4.
,‫ יעקב וילנצ'יק ועמנואל פלד‬,‫דוד אנדלמן‬
‫ אנרגיה אלקטרוכימית כאחת החלופות המרתקות והירוקות למנועי‬:‫מסוללות נטענות ועד תאי דלק‬
.5-2009 ‫ גלילאו‬,‫הבעירה‬
5.
S. Menkin, D. Golodnitsky, E. Peled,
Artificial solid-electrolyte interphase (SEI) for improved cycleability and safety of
lithium–ion cells for EV applications.
Electrochemistry Communications 11 ,1789–1791 (2009).
6.
H. Mazor, D. Golodnitsky and E. Peled,
High-Power Copper Sulfide Cathodes for Thin-film Microbatteries"
Electrochemical and Solid-State Letters, 12, 12 A232-A235 (2009).
7.
T. Ripenbein, D. Golodnitsky, M. Nathan, E. Peled,
Electroless Nickel Current Collector for 3D-Microbatteries.
Journal of Applied Electrochemistry, 2009 DOI 10.1007/s10800-009-0014-0.
8.
Y. Vilenchik, E. Peled and D. Andelman,
Kicking the oil addiction.
Physics World January (2010).
Patents
1.
E. Peled, T. Duvdevani, A. Blum, Livshits and A. Aharon
Fuel Cells System, Korean Pat No, 10- 0912157 (9. 2009).
2.
E. Peled, T. Duvdevani, A. Blum, Livshits and A. Aharon
Fuel Cell with PCM and with Improved water and Fuel Management
EP 1 410 453 B1 (03.09.2008).
3.
M. Nathan, E. Peled, D. Golodnitsky, E. Strauss, V Yufit
Thin Film Cathode for 3DMB, US Pat 7,527,897, 5-2009
Chinese patent, ZL200480037093.X (2009).
4.
M. Nathan, E. Peled, D. Golodnitsky,
Thin – film cathode for three – dimensional microbattery, and method for preparing
such cathode, US Pat appl. 60/418,718.
5.
E. Peled, D. Golodnitsky and H. Mazor; High-Power Nanoscale Cathodes for Thin-film
Microbatteries USPTO 61-236094- (23-8-2009).
■ Physical Chemistry and Electrochemistry
Dr. Shachar Richter
Visiting Scientist
Dr. Itay Carmeli
Doctoral Students
Netta Hendler
Noam Sidelman
Elad Mentovich
Masters Students
Michael Chechick
Amir Holtzman
Eyal Windler (External student)
Yaron Fruchtman
Roy Hakim
Research Projects
Molecular-based devices and circuits.
Molecular electronics suggests the use of a single molecule or a small array of molecules as
a fundamental unit for the construction of the future nano-electronic devices. A great effort is
being made to build individual molecules that could mimic the operation of the conventional
solid-state devices or even to construct new devices, the operation of which will be based on
molecular quantum phenomena. The progress in this field leads to important questions that
we are focusing on, such as the nature of conductivity of electroactive molecules, the role of
the molecule-electrode contact and the role of the intermolecular conductivity effect.
Recently we have demonstrated a novel molecular-based transistors and circuits in which
the electrical properties of various molecular systems can be explored.
Figure 1 Examples of several types of molecular systems measured using our nano devices.
a,b.
a two-terminal molecular device is used to explore the current vs. voltage
characteristics (I/V) of a redox-based molecular system (b). c,d A scheme of a Central gate
vertical molecular transistor and a carboxy fullerene system measured with it showing a
polaronic behavior. e. A scheme of a vertical molecular circuit.
Bio thin films and patterned structures
In the nanometric world, the intermix between different types of materials can give novel
types of composites that exhibit new and exciting properties. Nevertheless, since the
surface- to- volume ratio increases rapidly with decreasing size of the materials, some
unwanted aggregation processes can take place thus preventing the efficient mixing of the
materials. Another challenging obstacle in nano-composites is the incorporation of
hydrophilic and hydrophobic phases within one matrix. This problem becomes critical in
biomaterials composites since most of these compounds are hydrophilic thus difficulties are
arising to incorporate hydrophobic species inside them. In this context, of a special interest
is the family of bio-compounds which allow efficient up-taking of hydrophobic structures thus
can serve as a good matrix for bio-composites materials. We utilize special types of proteins
which exhibit extraordinary uptake properties to form new types of bio-composites materials.
Some examples of such systems are shown in Figure 2 (top). In a parallel effort we explore
the behavior of proteins adsorption patterns that occur on flat surfaces, when a voltage bias
is applied between near-by electrodes (Fig 2 bottom). Using various methodologies we
explore the electrokinetic and the dielectrophoresis of these phenomena.
Figure 2. Top (left).
light emitting bio-composite thin films. Top (right). Reinforced bio-
composite film. Bottom. Protein- lithography. Fluorescence microscopy (left) and simulation
of protein-patterned surface.
Properties Photovoltaic Cells from Photosynthetic Reaction Center.
Solar cells or photovoltaic cells (PVC) are becoming an important source for renewable
energy. The use of alternative energy sources is pertinent because of the increasing cost of
fossil oil, the adverse effect of pollution on the health and on the environment and the
prospect of future depletion of the oil reserves. We use nanotechnology and biotechnology
methodologies for the fabrication of PVC from photosynthetic reaction center proteins. Such
a device is superior to the present technology as it has an intrinsic quantum efficiency of 1, a
photo-potential of 1 V and can reach a theoretical energy conversion efficiency of 58%.
Tuning the properties of High-Tc superconductor using Self-Assembled monolayers.
We studied the possibility to absorb self-assembled organic monolayers (SAM) on the
surface of high-Tc cuprate superconductors (HTCS). When absorbtion on the surface of
different materials occurs, monolayers may create a strong dipole and charge transfer
to/from the surface. In high-Tc superconductors, that charge transfer can change the doping
level and the critical temperature. We focus on SAMs with surface dipole that can be
controlled by illumination (UV or visible). Our preliminary results indicate that the SAM
addition might change significantly the Tc temperature of the superconductor.
Collaborators
1.
Dr. Michael Gozin, School of Chemistry,TAU
2.
Proffesor Chanoch Carmeli, Biochemistry, TAU
3.
Dr. Yoram Dagan Physics, TAU
4.
Dr. Hagai Cohen, Weizmann Institute of Science
5.
Dr. Mukhles Sowwan ,Material Engineering Department, Al-Quds University,
Palestinian Authority
6.
Professor Andreas Herrmann, Groningen University, The Netherlands
Research Grants
2006-9
DFG (Germany)
2006-9
ISF
2007-8
US Air Force
2009
Clal-biotechnologies
Publications
1.
A. Tsukernik, A. Caster, N. Rosenberg-Shraga, H. Marom, M. Gozin , S. Richter,
Multipeak Negative-Differential--Resistance Molecular Device. E. Mentovich, I. Kalifa
Small, 4 , 55-58, (2008).
2.
A. Holtzman and S. Richter,
Cu and Ni-P electroless plating of silicon nitride using (3-aminopropyl)
triethoxysilane.
J. Electrochem.Soc. 155 D196-D202, (2008).
3.
Frolov L ,Y. Rosenwaks, Richter S, Carmeli C, I, Carmeli,
Photoelectric junctions between GaAs and photosynthetic reaction center protein. J.
Phys. Chem. C, 112 13426-13430, (2008) .
4.
Elad Mentovich , Bogdan Belgorodsky , Itsik Khalifa, S. Richter,
Large-scale fabrication of 4-nm-channel vertical -proteins ambipolar transistorNano Lett., 9 1296–1300, (2009).
5.
N. Sidelman,Y. Rosenberg; and S.Richter,
Peptide-based Spherulitic Films-formation and properties.
J.Col. Inter. In Press (published online http://dx.doi.org/10.1016/j.jcis.2009.11.028).
8T
8T
6.
E. Mentovich , N. Rosenberg-Shraga, I. Kalifa, A. Tsukernik, N. Hendler, M. Goziln
and, S. Richter,
High-yield fabrication of molecular vertical junctions.
J. Nanosci. Nanotec. Accepted.
7.
E. Mentovich and S. Richter,
Evaluation of leakage currents and the gate oxide in vertical molecular transistors.
Jpn. J. of Appl. Phys. Accepted.
8.
E. Mentovich, B. Belgorodsky and S. Richter,
Polaronic Molecular transistors .
Adv. Mat. Accepted.
9.
M. Sowann, M. Faroum A., E. Mentovich, I. Ibrahim, F.E. Alemdaroglu, M. Kwak, S.
Richter, Herrmann A.,
Electrical properties of DNA-Block Copolymer Nanoparticles. Submitted.
10.
I Carmeli, I. Lieberman, L. Kraversky, A. Govorov, G. Markovich and S. Richter .
Plasmon enhancement of the photosystem I assisted by metal nanoparticle
antennas. Submitted.
11.
E. Mentovich, B. Belgorodsky, M., H. Cohen and S. Richter,
Chemically controlled doping of gated molecular junctions. Submitted.
12.
E. Mentovich, I. Kalif, N. Shraga, G. Arvushenko and S. Richter,
Three Dimensional multifunctional molecular circuits. Submitted.
13.
E. Mentowich, D. K. Prusty , A. Herrmann and S. Richter,
DNA Conjugated Polymer Particle Networks: Macroscopic Materials with Nanosized
Features. Submitted.
Patents
1.
OPTOELECTRONIC DEVICE AND METHOD OF FABRICATING THE SAME
Granted on 28 April 2009 under the number 7,524,929.
2.
ELECTRIC NANODEVICE AND METHOD OF MANUFACTURING SAME. US
Patent, Europe patent PCT Treaty applications – PUBLISHED
3.
MOLECULAR ELECTRONIC DEVICES AND METHODS OF FABRICATING SAME.
US Patent, Europe patent PCT Treaty applications – PUBLISHED
4.
OPTOELECTRONIC DEVICE AND METHOD OF MANUFACTURING SAME. US
Patent, Europe patent PCT Treaty applications – PUBLISHED
5.
STABLE MUCINS' COMPLEXES WITH PAH's AND NANOMATERIALS. Provisional
patent in preparation.
■ Physical Chemistry and Electrochemistry
Dr. Yoram Selzer
Doctoral Students
Ilan Yutsis
Tamar Shamai
Ayelet Ophir
Debora Marchak
Gilad Noy
Eyal Shapira
Amir Holtzman
Naomi Ittah
Rani Arielly
Masters Students
Mattan Ben Zion
Koby Kfir (togeter with Prof. Ori Cheshnovsky)
Research Projects
Electronic transport through molecular wires and junctions has been attracting much
attention due to remarkable experimental and theoretical advances in recent years.
The influence of excitations by oscillating electromagnetic fields on electron transport
through molecular junctions is only starting to be experimentally addressed, and is the focus
of my current research.
From a fundamental point of view, external oscillating fields enable selective electron
excitations which could affect transport mechanisms, and thus could be envisioned as a new
type of molecular spectroscopy in which the input signal is photons and the output signal is
current2. Utilization of ultrashort laser pulses in this new tool will result in conductance
measurements with unprecedented temporal resolution.
From a practical point of view, time-dependent effects can be used to control and steer
currents coherently, thus establishing a prospective ‘hardware’ for future quantum
information technologies.
Since, typical energy scales of molecules are in the optical and infrared regime, where
today’s laser technology provides a wealth of coherent light sources, my research focuses
on various methods by which lasers could be used to affect and direct currents through
molecular junctions.
Probing of heating and cooling processes in current carrying nano-scale junctions.
Localized Joule heating poses a crucial question over the functionality and reliability of
nano-scale and molecular devices. The combination of small molecular heat capacity and
inefficient heat transfer away from these devices may cause a large temperature increase
that will affect their stability and integrity. The rate at which heat is transported away from a
conducting junction is, therefore, crucial to the successful realization of nanoelectronic
devices. To address these issues in molecular electronics, several experimental systems,
ranging from junctions based on molecular layers and single layer flakes of graphene, were
explored in our group enabling, for the first time, to measure heat conductance through
molecular junctions as well as the amount of heat dissipated on them by electrical currents.
The molecular heat capacity can be extracted from the data. Methods such as Surface
Enhanced Raman Spectroscopy (SERS), as well as Inelastic Electron Tunneling
Spectroscopy (IETS) have been used to analyze the modes by which energy is deposited
into junctions, as well as the means by which relaxation and heat dissipation is taking place.
The experimental systems are unique due to the broad range of information they supply on
various processes in molecular junctions. The results are expected to have impact on other
active research areas where understanding of heat conduction at the molecular level is
important, such as nanotribology.
Measurement of Electronic Transport through 1G 0 Gold Contacts under Laser
Irradiation.
Metal quantum point contacts (MQPCs) with dimensions comparable to the de Broglie
wavelength of conducting electrons, reveal ballistic transport of electrons and quantized
conductance in units of G 0 =2e2/h. While these contacts hold great promise for applications
such as coherent controlled devices and atomic switches, their realization is mainly based
on the scanning tunneling microscope (STM) and mechanically controlled break junction
(MCBJ), which cannot be integrated into electronic circuits. MQPCs produced by these
techniques have also limited stability at room temperature. We first reported on a new
method to form MQPCs with quantized conductance values in the range of 1-4G 0 . The
contacts appear to be stable at room temperature for hours and can be deterministically
switched between conductance values, or reform in case they break, using voltage pulses.
The method enables to integrate MQPCs within nano-scale circuits to fully harness their
unique advantages.
We then measured the transport properties of 1G 0 Au contacts under laser irradiation. The
observed enhancement of conductance appears to be wavelength-dependent, while thermal
effects on conductance are determined to be negligible. The results are consistent with a
photoasisted transport mechanism in which conductance depends both on the electronic
structure of the leads, and on the interaction of the transporting electrons with oscillating
electric fields originating from excitation of local plasmons. The results are important for
future interpretation of light effects on the conductance of molecular junctions.
Electrical detection of propagating plasmons by metal quantum point contacts.
Plasmonic waveguides offer promise in providing a solution to the bandwidth limitations of
classical electrical interconnections. Fast, low-loss and error-free signal transmission has
been achieved in long-range surface plasmon polariton waveguides. Deep subwavelength
plasmonic waveguides with short propagation lengths have also been demonstrated,
showing the possibility of matching the sizes of optics and today's electronic components.
However, in order to combine surface plasmon waveguides with electronic circuits, new
high-bandwidth electro-optical transducers need to be developed. Here, we experimentally
demonstrate the electrical detection of surface plasmon polaritons in metallic quantum point
contacts. By means of an integrated metal grating and a 1G 0 contact, highly confined
surface plasmon polaritons are detected and characterized. This approach of integrating
electro-optical components in metallic waveguides could lead to the development of
advanced active plasmonic devices and high-bandwidth on-chip plasmonic circuits.
Photoassisted Tunneling in Molecular Junctions.
We demonstrate controlled squeezing of visible light into molecular junctions serving as
optical cavities. The enhancement of measured conductance under irradiation is explained
by considering the dispersion relation of the cavities and by invoking photoassisted
tunneling mechanism as the governing effect on conductance.
One and zero-Dimensional ThermoElectric (TE) Cooling Devices
Thermoelectric devices hold great promise for cooling applications, with several important
advantages over conventional refrigerators such as all-solid-state operation, electronic
capacity control, reversibility which provides both cooling and heating, and high reliability.
The performance of TE devices depends on their figure of merit, ZT, which depends on the
Seebeck coefficient, electrical conductivity and thermal conductivity of the materials from
which they are built.
Currently state-of-the-art TE devices have a ZT value of ~1.5, while for comparison the
efficiency of standard refrigerators is equivalent to ZT~4.
One strategy to increase the efficiency of TE devices is to build them from one-dimensional
(1D) quantum wires, for which ZT values as high as 6 are expected for wires with a diameter
of 10nm. Such 1D wires can be potentially based on nano-wires of Bi, because of several
characteristics of this semi-metal.
We have developed unique methods to synthesize Bi nano-wires with the requested
dimensions. Our methods can be used to fabricate segmented nano-wires as well, which
are essentially stand-alone nano-TE devices that on one hand are not embedded in isolating
matrices and on the other hand could be inserted into composite materials if needed. The
synthesis method is unique as the wires are protected from oxidation, which is essential in
order to establish ohmic contacts to them. We are also developing experimental
methodologies to directly determine the ZT values of the Bi wires as well as any other 1Dstructured material.
Publications
1.
Sharabani R., Saada R., Noy G., Shapira E., Sadeh S. Selzer Y (PI),
Fabrication of very high aspect ratio metal nanowires by a self-propelling mechanism
Nano Lett., 8, 1169-1173 (2008).
2.
Shapira E., Marchak D., Tsukerik A., Selzer Y,
Segmented nanowires as nano-scale thermocouples
Nanotechnology, 19, 125501-125506 (2008).
3.
Ioffe Z. , Shamai T., Ophir A., Noy G., Yutsis I., Kfir K., Cheshnovsky O., Selzer Y,
Detection of Heating in Current Carrying Molecular Junctions by Raman Scattering.
Nature Nanotechnology, 3, 727 (2008).
4.
Itach N. Yutsis I., Selzer Y,
Fabrication of highly stable configurable metal quantum point contacts
Nano Lett., 8, 3922-3927 (2008).
5.
Ittah, N., Noy, G., Yutsis I., Selzer Y.,
Measurement of electronic transport through 1G 0 gold contacts under laser
irradiation.
Nano Lett. 9, 1615 (2009).
■ Physical Chemistry and Electrochemistry
Prof.Uri Shmueli
Research Projects
1.
Development of exact probabilistic approaches to structure-factor statistics.
2.
Effects of atomic heterogeneity and presence of dispersive scatterers on structurefactor statistics.
3.
Exact and approximate treatments of low-order structure invariants.
4.
Departures from Friedel's Law and resonant scattering of X-rays.
Collaborations
With Dr. Howard D. Flack, Laboratoire de Cristallographie, University
Of Geneva, Switzerland.
Publications and Books
1.
U, Shmueli, M. Schiltz and H. D. Flack
Intensity statistics of Friedel opposites.
Acta Crystallogr. A64, 476 - 483 (2008).
2.
U. Shmueli and H. D. Flack
Concise intensity statistics of Friedel opposites
and classification of the reflections.
Acta Crystallogr. A65, 322 - 325 (2009).
3.
U. Shmueli (Editor}
International Tables for Crystallography, Volume B: Reciprocal Space,
Third Edition.Edited by U. Shmueli, 686 + iv pp..
ISBN 978-1-4020-8205-4, ISBN (eREF) 978-1-4020-8206-1,
published for the IUCr by Springer (2008).
Note
In item (2) the derivation is done by purely statistical methods [unlike that in item (1)] and the
classification of the reflections encompasses all the crystallographic symmetries.
■ Physical Chemistry and Electrochemistry
Prof. Michael Urbakh
Head,
Department
of
Physical
Chemistry
and
Electrochemistry
Doctoral Students
Zion Tshiprut
Ronen Berkovich
Itay Barel
Dana Lichtenberg Fleishman
Masters Students
Stanislav Zelner
Senior Reseach Fellow
Dr. Leonid Daikhin
Research Projects
Atomic scale friction
Friction is present in a great number of physical systems and plays a central part in
phenomena that take place at all length scales, from micro- and nanomachines or biological
molecular motors to the geophysical scales characteristic for earthquakes. Despite the
practical and fundamental importance of friction and the growing efforts in the field, many
key aspects of dynamics of this phenomenon are still not well understood. The main
challenge is posed by the complexity of highly non-equilibrium processes occurring in any
tribological scenario that includes detachment and re-attachment of multiple microscopic
contacts between the surfaces in relative motion. We focus on a molecular level description
of processes occurring between, and close to, interacting surfaces which is needed to first
understand, and later manipulate friction. Methods for controlling friction using mechanical
and chemical approaches are introduced.
Fig.1. Scheme of typical experiments to study friction at the nanoscale. The main factors
that determine the friction between a tip and a surface are also shown.
Molecular Engines
We have introduced a new approach to build microscopic engines on the microscopic and
mesoscopic scales that move translationally or rotationally and can perform useful functions
such as pulling of a cargo. Characteristic of these engines is the possibility to determine
dynamically the directionality of the motion. The approach is based on the transformation of
internal vibrations of the moving object into directed motion, making use of the nonlinear
properties of friction. New mechanisms of effective molecular pumping and separation in
nano-channels have been proposed.
Dynamic Force Spectroscopy
Dynamic force spectroscopy provides an ability to measure adhesive interactions at the
single-molecule level with unprecedented resolution, and to achieve deeper insight in the
underlying mechanisms of molecular processes without the ‘‘scrambling’’ that occurs due to
ensemble averaging. To both explore the results of force spectroscopy experiments and to
reveal a molecular scale energy landscapes, we establish relationships between equilibrium
properties of the nanoscale systems and the characteristic features measured under nonequilibrium conditions.
Interfacial Electrochemistry of Complex Solid Surfaces.
Studies of well characterized, ‘ideal’ metal surfaces (liquid or single-crystal) is the corner
stone of modern fundamental electrochemistry. However, real electrodes used in
electocatalysis and energy conversion possess a huge, highly developed surface. A step
towards such systems on the fundamental level is the study of rough, disordered electrode
surfaces. The research here focuses on the theory of electrical double layer on rough
surfaces, and methods of surface characterization.
Fig. 2. Microscopic structure of double layer at an electrochemical interface.
Interfacial Soft Matter Electrochemistry: Structure, Dynamics, Functioning.
Electrochemistry of interfaces between two immiscible electrolyte solutions (ITIES) is a
progressing interdisciplinary field where soft matter physics and physical chemistry of liquids
meet molecular electrochemistry. We are interested in the full description of such systems,
including the structure of the interface, its electrical properties, and kinetics of charge
transfer across the interface.
Functionalization of ITIES is a hot area, driven by aspirations to build self-assembled
interfacial structures with unique properties, in particular, accessible to light from both sides
of the interface. Our analysis shows that semiconductor nanocrystals localized at the ITIES
should have electric-field-tunable optical properties across much of the visible spectrum.
Recently we proposed a new approach for electrically tunable reflection of light at a liquidliquid interface. Its operation principle relies on voltage controlled localization of metal nanoparticles at the interface.
For appropriate sizes and charges of the nanoparticles, and
concentration of the electrolytes, about half a volt potential variation is required to reversibly
convert the interface of two immiscible electrolytic solutions from a transparent window to a
mirror.
Fig.3. A cartoon of the light reflection from the monolayer of nanoparticles adsorbed at the
interface.
Electrowetting with Electrolyte Solutions
We have introduced a novel electrowetting system containing an interface between two
immiscible electrolytic solutions (ITIES) that can change its shape under a small voltage
variation, which are two orders of magnitude lower than in conventional systems. Our
research focuses on modeling ITIES-based electrically tunable optical devices.
Fig.4. Charge accumulation at an interface between two immiscible electrolytic solutions on
an electrode.
Probing the Solid-Liquid Interface with the Quartz Crystal Microbalance (QCM)
We have introduced theoretical models for the mechanical contact between the oscillating
quarts crystal and the liquid which take into account the structure and dynamics at this
interface. The main question, which we would like to answer, is what information on the
properties of the solid-liquid interface can be extracted from the QCM experiments.
Fig.5. Schematic view of coupling between shear waves and molecules at a quartz crystal liquid interface.
Collaborations
1.
Prof. A.A. Kornyshev, Imperial College, London, UK
2.
Prof. E. Meyer, Universty of Basel, Switzerland
3.
Prof. A.E. Filippov, Institute for Physics and Engineering, Donetsk, Ukraine
4.
Prof. J.W.M. Frenken, Leiden University, Nethrland
5.
Prof. J. Fineberg, Hebrew University, Jerusalem, Israel
6.
Prof. E. Tosatti, Sissa, Trieste, Italy
7.
Dr. A. Vanossi, Sissa, Trieste, Italy
8.
Prof. M.E. Flatte, University of Iowa, USA
9.
Prof. O.M. Braun, Institute of Physics, Kiev, Ukraine.
Memberships in Learned Societies
1.
Israel Chemical Society.
2.
American Chemical Society.
3.
Material Research Society, USA.
Research Grants
2005-2008
The Israel Science Foundation, Structure and Dynamics of Interfaces
between Two Immiscible Electrolyte Solutions.
2005-2008
The Israel Science Foundation, Bikura, Dynamic Control of Friction
2004-2008
Deutsche Forschungsgemeinschaft (DFG), Single Molecules: From
Observation to Manipulation.
2008-2012
EUROCORE-theme program (ESF), Friction and Adhesion in
Nanomechanical
2009-2013
Systems.
The Israel Science Foundation, Electrowetting under electrochemical
control: Interfaces between two immiscible electrolytic solutions.
Publications
1.
Daikhin L.I., Urbakh M.,
What is the origin of irregular current oscillations in the transfer of ionic
surfactants across liquid/liquid interfaces?,
J. Chem. Phys. 128, Art. 014706 (2008).
2.
Flatte M. E., Kornyshev A.A., Urbakh M.,
Understanding voltage-induced localization of nanoparticles at a liquid-liquid
interface,
J. Phys.: Cond Matter. 20, Art. 073102 (2008).
3.
Filippov A.E., Dienwiebel M., Frenken J.W.M., Klafter J., Urbakh M.,
Torque and twist against superlubricity,
Phys. Rev. Lett. 100, Art. 046102 (2008).
4.
Tshiprut Z., Filippov A.E., Urbakh M.,
Effect of tip flexibility on stick-slip motion in friction force microscopy
experiments,
J. Phys.: Cond. Matter, 20 Art. 354002 (2008).
5.
Berkovich R., Klafter J., Urbakh M.,
Analyzing friction forces with the Jarzynski equality,
J. Phys.: Cond. Matter, 20, Art. 354008 (2008).
6.
Tshiprut Z., Klafter J., Urbakh M.,
Single-molecule pulling experiments: When the stiffness of the pulling device
matters,
Biophys. J. 95, L42-L4 (2008).
7.
Guerra R., Vanossi A. and Urbakh M.,
Controlling microscopic friction through mechanical oscillations,
Phys. Rev. E 78, Art. 036110 (2008).
8.
Monroe C. W., Urbakh M., and Kornyshev A. A.,
Double-layer effects in electrowetting with two conductive liquids,
J. Electrochem. Soc. 156, 21-28 (2009).
9.
Flatte M., Kornyshev A.A., Urbakh M.,
Giant Stark effect in quantum dots at liquid/liquid interfaces: A new option for
tunable optical filters,
PNAS, 105, 18212–18214 (2008).
10.
Z. Tshiprut, S. Zelner, and M. Urbakh,
Temperature-Induced Enhancement of Nanoscale Friction,
Phys. Rev. Lett., 102, 136102 (2009).
11.
Z. Tshiprut and M. Urbakh,
Exploring hysteresis and energy dissipation in single-molecule force
spectroscopy,
J. Chem. Phys. 130, 084703 (2009).
12.
Filippov A.E., Vanossi A., Urbakh M.,
Rotary motors sliding along surfaces,
Phys. Rev. E, 79, 021108 ( 2009).
13
Braun O. M, Barel I, Urbakh M.
Dynamics of Transition from Static to Kinetic Friction,
Phys. Rev. Lett., 103, 194301 (2009).
14
Flatte M., Kornyshev A.A., Urbakh M.
Nanoparticles at electrified liquid-liquid interfaces: new options for electrooptics,
Faraday Discussions, 143, 109-115 (2009)
■ Chemical Physics
Prof. Aviv Amirav
The Chair of Analytical Chemistry
Website: http://www.tau.ac.il/chemistry/amirav
Technical Staff
Dr. Alexander Fialkov
Doctoral Students
Alexander Gordin
Tal Alon
Mati Morag
Marina Poliak
Major Research Interest and Projects
The research is aimed towards the development of novel analytical instrumentation and their
related new methods to aid the detection and analysis in a broad range of samples and
applications including environmental, fuels, food, forensic, clinical toxicology, pharmaceuticals
and medical.
Patents and their availability in the form of new analytical instruments in worldwide use is the
prime target of our research. Special emphasis is given to collaborations with the international
analytical instrument industry.
Current major research projects include:
1.
Supersonic GC-MS – The Quest for Ultimate Performance GC-MS.
2.
Supersonic LC-MS – Electron Ionization LC-MS for automated library based
compound identification.
3.
Supersonic Electrospray – Combining Electrospray Ionization with Supersonic
Molecular Beams.
4.
GCxGC-MS with Supersonic Molecular Beams.
5.
LCxGC and LCxGC-MS with Supersonic Molecular Beams.
6.
Novel spray methods for sample ionization and vaporization.
7.
Supersonic Fast GC-MS
8.
Open Probe for fast sampling and mass spectrometry analysis
Research Grants
1.
Comprehensive Two Dimensional Chromatography Mass Spectrometry
with Supersonic Molecular Beams.
Israel Science Foundation (ISF), 10/07-9/11
2.
Ultra-Fast Methods and Instrumentation for the Analysis of Hazardous Chemicals in the
Food Supply.
BARD- USA-Israel Binational Agricultural Fund, 10/09-9/12
3.
Novel (On-Line) Analytical Techniques for the analysis of Micropollutants in water:
Technique Development and Environmental Applications.
Ministry of Science Tashtiot program grant for Professors Ovadia Lev, Israel
Schechter and Aviv Amirav, 10/09-9/12
Publications
1.
Marina Poliak, Maya Kochman and Aviv Amirav.,
"Pulsed Flow Modulation Comprehensive Two Dimensional Gas Chromatography"
J. Chromatogr. A. 1186, 189-195 (2008).
2.
Aviv Amirav, Alexander Gordin, Marina Poliak, and Alexander B. Fialkov
"Gas Chromatography Mass Spectrometry with Supersonic Molecular Beams"
Invited Special Feature Perspective Article.
J. Mass Spectrom. 43, 141-163 (2008).
3.
Alexander B. Fialkov, Alexander Gordin and Aviv Amirav
"Hydrocarbons and Fuels Analysis with the Supersonic GC-MS – The Novel Concept of
Isomer Abundance Analysis"
J. Chromatogr. A. 1195, 127-135 (2008).
4.
Alexander Gordin, Aviv Amirav and Alexander B. Fialkov.,
"Classical Electron Ionization Mass Spectra in Gas Chromatography/Mass Spectrometry
with with Supersonic Molecular Beams"
Rapid. Commun. Mass Spectrom. 22, 2660-2666 (2008).
5.
Marina Poliak, Alexander B. Fialkov and Aviv Amirav.,
"Pulsed Flow Modulation Two-Dimensional Comprehensive Gas Chromatography
Tandem Mass Spectrometry with Supersonic Molecular Beams".
J. Chromatogr. A 1210, 108-114 (2008).
6.
Steven J. Lehotay, Katerina Mastovska, Aviv Amirav, Alexander B. Fialkov, Perry A.
Martos, André de Kok and Amadeo R. Fernández-Alba.,
"Aspects in the Identification and Confirmation of Chemical Residues by
Chromatography/Mass Spectrometry and Other Techniques".
Trends in Analytical Chemistry (TrAC) 27, 1070-1090 (2008).
7.
Ilia Brondz, Alexander B. Fialkov and Aviv Amirav.,
Analysis of Quinocide in Unprocessed Primaquine Diphosphate and Primaquine
Diphosphate Tablets Using Gas Chromatography-Mass Spectrometry with Supersonic
Molecular Beams.
J. Chromatogr. A. 1216, 824-829 (2009).
8. Tal Alon and Aviv Amirav.,
"Isotope Abundance Analysis for Improved Sample Identification with Tandem Mass
Spectrometry".
Rapid Commun. Mass Spectrom. 23, 1-5 (2009).
9.
Marina Poliak, Alexander Gordin and Aviv Amirav.,
"Open Probe – A Novel Method and Device for Ultra Fast Electron Ionization Mass
Spectrometry Analysis" (In preparation).
10. Alexander B. Fialkov, Mati Morag and Aviv Amirav
"Fast GC-MS with Supersonic Molecular Beams" (In Preparation).
Patents
1.
Aviv Amirav and Alexander Gordin .
"Open Probe Method and Device for Sample Introduction for Mass Spectrometry
Analysis" .
Israel patent application number 193003 filed on July 23, 2008.
USA patent application number 12/469,779 filed on May 21, 2009.
Japan patent application number 2009-162366 filed on July 9, 2009 .
2.
Aviv Amirav and Alexander B. Fialkov.
“Fast Gas Chromatograph Method and Device for Analyzing a Sample in a Supersonic
Molecular Beam".
In process of patent application.
■ Chemical Physics
Prof. (Emeritus) Abraham Ben-Reuven
Academic Staff
Dr. Vladimir A. Yurovsky (Senior Research Associate).
Research Projects
1.
Association and spontaneous dissociation of molecular Bose-Einstein condensates
with formation of entangled atoms in squeezed states.
2.
Ultracold atom-molecule collisions in atom waveguides: One-dimensional Bose
chemistry.
3.
Solution of the one-dimensional three-body problem with resonant interaction.
4.
Atom-molecule solitons in ultracold gases.
5.
Observable effects of integrability and non-integrability in quasi-one-dimensional
Systems.
6.
Quantum chaos with ultracold atoms.
Scientific Committees
Council Member, The Wolf Foundation.
Collaborations
1.
Prof. Maxim Olshanii, University of Massachusetts, Boston MA.
2.
3.
4.
Prof. David S. Weiss, Penn State University, State College PA.
Prof. Yehuda B. Band, Ben-Gurion University, Beer-Sheva, Israel.
Prof. Boris A. Malomed, Tel Aviv University, Tel Aviv, Israel.
Publications
1.
Yurovsky V. A. Effects of non-integrability on stabilization of Feshbach molecules in
atom waveguides. Phys. Rev. A 77, 012716 (2008).
2.
Yurovsky V. A. Faddeev equations in one-dimensional problems with resonant
interactions. Phys. Rev. A. 80, 022701 (2009).
Chapters in Books
1.
Yurovsky V. A., Olshanii, M., Weiss D. S. Collisions, correlations, and integrability in
atom waveguides. In Adv. At. Mol. Opt. Phys., vol. 55,61-138 (Elsvier Academic Press,
New York, 2008).
Invited Talks at Conferences
1.
Yurovsky V.A. Non-integrability in atom waveguides, LPHYS'07, Leon, 2007.
2.
Yurovsky V.A. Effect of non-integrability on reactions and collisions in quasi-onedimensional ultracold gases, Batsheva de Rothschild Seminar on ultrafast-ultracold
processes, Ein-Gedi, Israel, 2008.
3.
Yurovsky V.A. Mechanisms of thermalization in two-dimensional optical lattices,
LPHYS'08, Trondheim, 2008.
4.
Yurovsky V.A., Olshanii M. Quantum chaos with ultracold atoms, LPHYS'09, Barcelona,
2009.
■ Chemical Physics
Prof. (Emeritus) Mordechai Bixon
8T
Research Projects
8TU
1.
2.
Basic problems in electron transfer theory.
6T
6T
Theory of charge transfer in biomolecules.
■ Chemical Physics
Prof. Ori Cheshnovsky
The Raymond and Beverly Sackler Chair in Clusters and Nanoparticles
Research Staff
Dr. Rina Giniger
Doctoral Students
Yuri Vinshtein
Zvi Ioffe
Denis Glozman
Israel Wolf
Masters Students
U
Efrat Prigal
Diana Dermer
Kobi Kfir
Doron Azuri
Omer Wagner
Collaborations
U
1.
Daniel M. Neumark, University of California, Berkeley, USA.
2.
Bernd V. Issendorff, University of Freiburg, Germany.
3.
Yael Hanein, School of Electrical Engineering, Tel Aviv University.
4.
Yoram Selzer, School of Chemistry, Tel Aviv University.
Research Grants
U
1.
U.S. - Israel Binational Science Foundation.
"Excited States in Anionic Clusters" 10.05 - 9.08.
2.
The Israel Science Foundation.
“Studies of Nanometric Systems by Raman Spectroscopy and Light-STM” 10.08 9.12.
3.
James Franck Binational German-Israel Program.
"Laser Matter Interactions" 1989-2012.
4.
Raymond and Beverly Sackler Chair in Clusters and Nanoparticles.
Scientific Committees and Boards:
International advisory board for The International Symposium on Molecular Beams, 1990International advisory board for The International Symposium on Small Particles and
Inorganic Clusters, 1994Director of the Center for NanoScience and Nanotechnology 2004Prizes
1.
The Weizmann Prize in Exact Sciences
2.
Fellow of the American Physical Society
Raman Spectroscopy and Mapping of nano-Molecular Structures
Acquisition of spatially-resolved enhanced Raman spectra, within molecular conduction
structures (such as molecular tunneling junctions and carbon nanotubes), provides useful
chemical information about the molecules in the nano-structures and their vibrational
excitation processes.
A new generation of our home-built Confocal Raman Microscope (CRM) system creates
"chemical maps" at cold temperatures (77K) by raster scanning the Raman scattering of a
sample. The system uses high-NA objective for the sample illumination and Raman light
collection. Piezo-controlled XY stage scans sample. The resulting spatially-resolved spectral
analysis allows chemical examination at molecular scale. Following is an example of Raman
Microscopy oriented projects:
Detection of Heating in Current Carrying Molecular Junctions by Raman Scattering
An important consequence of electron-vibration interaction in molecular-junction-transport is heat
generation, i.e., energy transfer to the underlying nuclear motions. In balance with heat
dissipation, this has important implications on the issue of junction stability. Advancement in
molecular electronics necessitates thorough understanding of these processes in molecular
junctions1-4. Such an understanding depends on the ability to monitor non-equilibrium occupancy
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of vibrational levels at current carrying junctions as a function of bias. We report on the
realization of such a capability by utilizing the Stokes (S) and AntiStokes (AS) components of
Surface Enhanced Raman Spectroscopy (SERS) to probe the effective temperature of current
carrying junctions. In our specific junction, all Raman active modes show similar heating as a
function of bias at room temperature, suggesting fast internal vibrational relaxation processes.
These results demonstrate the power of direct spectroscopic probing of heating and cooling
processes in nanostructures.
Research Projects
Figure 1: Raman spectra and maps of a junction. (a) Raman spectrum in the Stokes
regime using the 671nm laser, of BPDT molecules in a junction (black) and as a monolayer at
an arbitrary spot on the Ag electrode (red). (b) The corresponding anti-Stokes spectrum. (c)
An optical picture showing a top view of a junction. (d) A Raman map of a junction based on
the 1585cm-1 Stokes line. The enhancement of signal at the junction is shown as brighter
pixels. The points at which the spectra at (a) were taken are indicated by arrows. (e) A Raman
map of the 1585cm-1 AS line of the same junction.
Light, tunneling junctions and nanoparticles:
In this project, we study the correlation between the electrical properties and the optical
properties of isolated nanocrystals or polymeric films. The sample, deposited on a surface, is
studied using scanning Tunneling Microscope (STM). The transport properties of the sample
are measured using I-V spectroscopy. In parallel, on the same particle, light emission induce
by inelastic tunneling is monitored, using a dedicated home-built STM head. A major virtue
of the project is that the optical and electrical measurements are performed on the same
single isolated nanoparticle. Various semiconductor core-shell nano-dots and nano-rods are
studied. In the case in which the particle is inhomogeneous, it's different light emitting parts
are differentiated. The same methods will serve in studying the relation between the
morphology segregation and light emission in multi-chromophor polymeric films.
II.
I.
STM measurement of a single CdSe nanocrystal on Au substrate.
I.) Surface topography II.) Photon emission map revealing high
Clusters and photoelectrons:
Electron Kinetic Energy [ eV ]
1
Photoelectron spectroscopy is used to interrogate basic processes
Problems such as solvation of electrons, critical sizes for proton
transfer and dissociation of complexes in extremely small solvent
clusters are addressed. See for example:
Two Photon Detachment of d Electrons and Auger Emission in
D5/2 3
Hgn-
2P Photoelectron Signal Intensity [a.u ]
of solvation chemistry in small mass selected clusters systems.
2
D3/2
n=9n=9
15 15
30 30
45 45
60 60
120 120
180 180
Photoelectron Studies of Hg n - Clusters.
280 280
We report on two-photon photoelectron spectra of negatively
12
11
10
2P Binding Energy [eV ]
-
charged mercury clusters, Hg n , excited by 6.43 eV photon energy. The two-photon spectra
include narrow bands attributed to inner shell d electron detachment. The position and shape
of the d core detachment peaks hardly change over the size range of n= 9-280. The spectra
also include broad bands, consistent with the anticipated kinetic energies of the Auger
electrons. To the best of our knowledge, this is the first time that an internal-shell Auger
electron has been identified in the photoelectron spectra of free metallic clusters.
Recent Publications
1.
Griffin G.B., Kammrath A. Ehrler O.T., Young R.M., Cheshnovsky O, and Neumark
D.M.,
Auger recombination dynamics in Hg- 13 clusters.
Chem. Physics Vol. 350 ,pp. 69-74 (2008).
2.
Wolf I, Shapira A, Giniger R, Miller Y, Gerber R. B, Cheshnovsky O.,
Critical Size for Intracluster Proton Transfer from Water to an Anion.
Angew. Chem. Int. Ed. Vol. 47, pp: 6272-6274 (2008).
3.
Ioffe Z. Shamai T., Ophir A., Noy G., Yutsis I., Kfir K., Cheshnovsky O., Selzer Y.,
Detection of Heating in Current Carrying Molecular Junctions by Raman Scattering.
Nature Nanotechnology Vol. 3, pp. 727-732 (2008)..
4.
Griffin GB, Ehrler OT, Kammrath A, Young RM, Cheshnovsky O, Neumark DM.,
Auger recombination and excited state relaxation dynamics in Hg-n(-) (n=9-20) anion
clusters.
J. Chem. Phys. Volume 130 no. 231103 (2009).
5.
Karp GA, Ya'akobovitz A, David-Pur M, Ioffe Z, Cheshnovsky O, Krylov S, Hanein Y
Integration of suspended carbon nanotubes into micro-fabricated devices.
Journal of Micromechanucs and microengineering Volume 19, Number: 085021
(2009).
6.
Young RM, Griffin GB, Ehrler OT, Kammrath A, Bragg AE, Verlet JRR, Cheshnovsky
O, Neumark DM .,
Charge carrier dynamics in semiconducting mercury cluster anions.
Physica Scripta Volume 80, 048102 (2009).
■ Chemical Physics
Prof. Sergey Cheskis
Doctoral Students
U
Anatoly Goldman
Masters Students
U
Leonid Nichman
Amir Hevrony (in cooperation with Prof. Gil Markovich)
Hadar Golan
Alexey Fomin
Research Projects
U
Intracavity Laser Absorption Spectroscopy (ICLAS)
Figure 1 ICLAS dye laser
ICLAS is a method in which absorbing species are placed inside the cavity of a broadband
laser .Due to the positive feedback mechanism in lasers, even minute quantities of a narrowline absorber will produce holes in the spectrum where the laser output is partially quenched.
ICLAS was first proposed more than thirty years ago, and since then has been the subject of
hundreds of papers and several review articles. Our own extensive experiments with ICLAS in
flames have shown that this is probably the most sensitive of the absorption spectroscopy
methods considered. ICLAS has several important advantages over CRDS, mainly:
1. The sensitivity of ICLAS is higher because it can attain longer optical paths.
2. In ICLAS, a CCD detector collects information from several thousand wavelength
channels simultaneously during a single pulse. Thus, the time required to obtain a
given amount of spectral information is several orders of magnitude shorter for ICLAS
than for CRDS or LIF.
3. Since ICLAS tolerates relatively high broadband losses in the cavity, optical windows
can be used to separate the cavity from the flame region. Experiments with sooty
flames are also possible with ICLAS. We have used ICLAS extensively for
concentration measurements in low-pressure flames.
4. More recently we have started using FLICAS, a modified ICLAS technique based on
IR fiber lasers . In the proposed research, this variant will be used to monitor H 2 S, CO,
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and CO 2 molecules in the 1.5 μm range of the spectrum .
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Fiber Laser Intracavity Absorption Spectroscopy (FLICAS)
Figure 2 FLICAS
Various lasers, such as, dye, solid state and fiber lasers have been used successfully for
intracavity absorption measurements: So far, the highest sensitivity to intracavity absorption
has been achieved with a dye laser, where effective absorption path lengths of up to 70,000
km have been demonstrated in the visible spectral range .
However, doped fiber lasers are more suitable for the design of compact and inexpensive gas
analyzers for practical field measurements, since they require substantially less pump power
than other lasers and emit a broad spectrum in the near infrared range where many molecular
species show strong absorption. Inhomogeneous broadening of the gain allows simultaneous
measurements in a broad spectral range without tuning .
Intracavity absorption measurements in the combustion environment can be easily performed
with an Er+3-doped fiber laser. Most of the components of this laser are very well developed
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for telecommunication and they are readily available. Tuning range extends from 1.527 µm to
1.613 µm and includes strong absorption of many atmospheric and combustion relevant
molecules, such as CO,CO 2 , OH , HCN, C 2 H 2 , H 2 S, NH 3 ,CH 4 , H 2 O and HI and it is almost
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free from strong water vapor absorption lines ,typical for other lasers.
Low pressure flat flame
Figure 3 Low pressure flat flame
A low-pressure flat flame is very suitable for laser diagnostics due to its quasi-onedimensional structure. This makes it rather simple to compare experimental results to
computer models. In a low-pressure system, the flame front is also wide enough to recover
detailed information on the concentration profiles of various species. In our laboratory we built
a large vacuum chamber (40 cm in diameter) containing a porous plug McKenna burner 6 cm
in diameter. The burner can be displaced in the vertical and horizontal directions with very
high precision, allowing for tomographic reconstruction of the flame with line-of-sight
spectroscopy Our research group has extensive experience with this kind of flame and with
several different laser spectroscopy methods, including intracavity laser absorption
spectroscopy
(ICLAS), cavity
ring
down
spectroscopy
(CRDS),
and laser-induced
fluorescence (LIF).
Particle mass spectrometer
In order to investigate the processes of the synthesis in flames a particle mass spectrometer
has been built. This apparatus allows the measurement of the mass of the particles basing on
the deflection of the charged particles in the electric field. The particles forming in flames are
sampled by the injection to the supersonic molecular beam, and can be collected later for
analysis using an electron microscope.
Figure 4 Particle mass spectrometer with combustion chamber
Sulfur related light emission from flames
Even a small amount of sulfur produces blue-violet chemiluminescence. A mechanism
producing electronically excited S 2 molecules is not fully understood. Two possibilities are
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normally considered: direct recombination of sulfur atoms
S + S + M = S 2 * + M (1)
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and energy transfer to S 2 molecules in the ground state, for example
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H + H + S 2 = S 2 * + H 2 (2)
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By studying laser-induced fluorescence (LIF) and chemiluminescence in a pulsed propagated
flame doped with sulfur compounds, we have found that reaction (1) is probably the main
source of excited sulfur molecules. Unfortunately, this experiment failed to give an
unambiguous proof.Another important fact which demands explanation is the enhancement of
emission obtained by introducing a cool body into the flame .
Figure 5 H 2 S doped hydocarbon flat flame
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Flame assisted nanoparticle synthesis
At the nanoscale, many materials display properties that differ from their corresponding bulk
behavior, which makes them attractive in studies in chemistry and material science. There are
many current studies on the properties of oxide nanocrystals, and therefore, an efficient
method for their production is essential. One of the most common methods to get oxide
nanoparticles is by flame pyrolysis. This study is an attempt to develop a robust method to
produce oxide nanocrystals from liquid-phase precursor solutions in low-pressure premix
flames. One of the goals of the study is to be able to control the size of the particles produced.
It can be possible by varying the flame parameters, the collection site location, and/or the
precursor concentration. For this goal the special low pressure flame apparatus was designed
and built. In this study, a special reaction chamber was built, and iron oxide nanocrystals were
produced using the two methods .
Figure 6 Na containing spray in combustion chamber
Figure 7 Diffraction pattern of nanoparticles formed in flame
Collaborations
1.
Prof. Gregory Sivashinsky, School of Mathematical Sciences, Tel Aviv University, Israel.
2.
Prof. Jurgen Wolfrum, University of Heidelberg, Germany
3.
Dr. Valery Baev, University of Hamburg, Germany
Research Grants
2005-2007
The Israel Science Foundation, Heterogeneous effects in nitrogen chemistry
in flames .
1997-2007
James Franck, German-Israeli Binational Program in Laser Matter Interaction
Scientific Committees and Boards:
Chair of The Israeli Section of The Combustion Institute
Publications
Articles
1.
S .Cheskis., A. Goldman.,
Laser diagnostics of trace species in low pressure flat flame.
Prog. Energy Comb. Sci 35, 365-382 (2009).
2.
A .Goldman., S. Cheskis.,
Intracavity laser absorption spectroscopy of sooting acetylene / air flames.
Phys. B 92, 281 – 286 (2008).
3.
I .Rahinov., A. Goldman., S. Cheskis.,
Intracavity laser absorption spectroscopy for flame diagnostics.
Isr. J .Chem. , 47, 131 – 140 (2007).
Appl.
■ Chemical Physics
Prof. Haim Diamant
Post-Doctoral Researcher
Dr. Derek Frydel
Doctoral Students
Emir Haleva
Radina Hadgiivanova
Naomi Oppenheimer
Masters Students
Kobi Barkan (jointly with Prof. Ron Lifshitz, School of Physics).
Research Projects
A wide variety of natural and industrial materials behave neither as crystalline solids nor as
simple liquids. They are referred to as complex fluids or soft matter. Examples include liquid
crystals, suspensions, emulsions, polymer solutions, solutions of self-assembling molecules,
and biological systems. These materials exhibit an overwhelming richness of structures and
dynamic behaviors, whose theoretical understanding is the aim of our research.
•
Interactions between confined particles. We have been investigating the interactions
between particles of nanometer-to-micron size, suspended in a liquid and confined in
various geometries, e.g., between two plates or in narrow channels. Such confined
suspensions are encountered in various systems, such as porous media, micro- and nanofluidic devices, and biological constrictions. We have demonstrated that confinement
dramatically modifies medium-induced interactions such as hydrodynamic interactions
(flow-mediated drag forces).
•
Correlated diffusion of membrane proteins. We have studied the correlated motion of
proteins embedded in a fluid biomembrane, along with the effect of protein concentration
on that correlation and on the effective response of the membrane to stresses. We found
hydrodynamically induced long-range correlations and anomalous concentration effects.
Qualitative differences between freely floating and supported membranes were indicated.
•
Statistical thermodynamics of particle-encapsulating vesicles. Mesoscopic fluctuating
envelopes (vesicles or liposomes), encapsulating a fixed number of solute molecules, are
ubiquitous in the function of biological cells and in various biomedical and cosmetic
applications. We have characterized the statistical mechanics of particle-encapsulaing
random manifolds, highlighting the qualitative differences between these systems and
those controlled by a pressure difference across the envelope. We have also analyzed the
swelling of actual particle-encapsulaing vesicles as they approach their maximum volume
and ultimate osmotic lysis, discovering a new type of critical behavior.
•
Instability of fluid monolayers. Mono-molecular films of surface-active molecules at
water–air or water–oil interfaces are abundant in biology and industrial processes. An
important example is the surfactant monolayer covering the lungs, whose main function is
to lower the surface tension and thus reduce the mechanical work of breathing. Laterally
compressed monolayers have been found to undergo a curious structural instability in the
form of localized folding, which is believed to be important for the function of lungs. We
have been studying the elastic and dynamic response to lateral compression of such
monolayers overlying a liquid phase.
•
Aggregation of amphiphilic molecules. We have constructed a new formalism for
aggregation of amphiphilic molecules in solution (micellization), which allows the study of
metastable micelles and the kinetics of micelle formation. We have shown that metastable
micelles (premicellar aggregates), once formed, may have a macroscopic lifetime and
small polydispersity.
•
Rayleigh instability of curved liquid domains. We have demonstrated the occurrence
of a localized (rather than the usual extended) Rayleigh instability in a curved liquid
filament supported on a solid substrate. This instability plays a crucial role in the dynamics
of evaporation of thin liquid films off solid surfaces
•
Soft quasicrystals. Following recent experimental discoveries of quasiperiodic order in
soft-matter (liquid-crystalline) systems, we have demonstrated the possibility to stabilize
such structures in single-component systems of isotropic, soft particles.
Collaborations
1. Thomas A. Witten and Ka Yee C. Lee, University of Chicago. Instabilities in surfactant
monolayers.
2. Stuart A. Rice and Binhua Lin, University of Chicago. Confined colloidal suspensions.
3. Ron Lifshitz, Tel Aviv University. Soft quasicrystals.
4. Oded Agam, Hebrew University. Curved liquid domains.
5. David Andelman, Tel Aviv University. Kinetics of micellization.
6. Yael Roichman, Tel Aviv University. Colloidal rings.
Membership in Learned Societies
1. Israel Chemical Society
2. Israel Physical Society
3. American Chemical Society
4. American Physical Society
Research Grants
2006-2010 Israel Science Foundation, "Dynamics of quasi-two-dimensional suspensions
with applications to biomembranes".
2006-2009
Israel Science Foundation (Co-Investigator), "Soft quasicrystals".
2007-2011 US-Israel Binational Science Foundation, "Microrheology and instability of
compressed surfactant monolayers".
2007-2010
American Chemical Society Petroleum Research Fund, "Statistical
thermodynamics of solutions enclosed in fluctuating semipermeable capsules".
2009-2013
NanoScience Europe, "Directed and autonomous motion
of hybrid magnetic nano-objects".
Publications
Chapters in Books
1.
H. Diamant.
Long-range hydrodynamic response of complex liquids. In Continuum Models and
Discrete Systems, D. Jeulin and S. Forest (eds.), Mines Paris, pp. 51-56 (2008).
Articles
1.
E. Haleva and H. Diamant.
Critical swelling of particle-encapsulating vesicles.
Phys. Rev. Lett. 101, 078104 (2008).
2.
E. Haleva and H. Diamant.
Swelling of particle-encapsulating random manifolds.
Phys. Rev. E 75, 021132 (2008).
3.
H. Diamant.
Hydrodynamic interaction in confined geometries (review).
J. Phys. Soc. Jpn. 78, 041002 (2009).
4.
N. Oppenheimer and H. Diamant.
Correlated diffusion of membrane proteins and their effect on membrane
viscosity.
Biophys. J. 96, 3041 (2009).
5.
6.
R. Hadgiivanova and H. Diamant.
Premicellar aggregation of amphiphilic
polydispersity.
J. Chem. Phys. 130, 114901 (2009).
molecules:
aggregate
lifetime
and
H. Diamant and O. Agam.
Localized Rayleigh instability in evaporation fronts. Phys. Rev. Lett., accepted; e-print
http://arxiv.org/abs/0909.4400
More Information on the Web
http://www.tau.ac.il/~hdiamant
■ Chemical Physics
Prof. (Emeritus) Uzi Even
The Joshua Jortner Chair in Chemistry
Technical Staff
Yacov Magen
Doctoral Students
Kfir Luria
Masters students
Dani Wasserman
Shauli Daon
Research Projects
1.
Ultra cold molecular spectroscopy.
2.
Quantum properties of Helium clusters on aromatic molecules.
3.
Cluster Impact surface chemistry.
4.
Sources of molecular radical and excited atoms
Research Grants
2007-2010
German Israel Fund
2002-2010
James Franck foundatrion for laser matter interaction.
2003-2009
Israel National Fund
Publications
1.
N.Edvardas, L.Adam, P.G.Christian,C.Isaac, N.Julia, E.Uzi, and G.R. Mark G.,
Stopping Supersonic Beams with a Series of Pulsed Electromagnetic Coils: An
Atomic Coilgun.
Phys. Rev. Lett. 100, 093003. (issue of 7 March 2008).
2.
N.Edvardas, L.Adam, P.G.Christian,C.Isaac, N.Julia, E.Uzi, and G.R. Mark G.,
Stopping supersonic oxygen with a series of pulsed electromagnetic coils: A molecular
coilgun.
Phys. Rev.A 77, 051401_R (2008).
3.
P.Dominik, R.Ricarda,D. Bernhard, S.Alkwin,E.Uzi, L.Nachum,B. Raviv, and L.
Kfir.
Rapidly pulsed helium droplet source.
Review of Scientific Instruments 80, 043302 (2009).
4.
L. Kfir, L.Nachum, and E.Uzi.,
Dielectric barrier discahrge source for supersonic beams.
Review of Scientific Instruments 80, 104102 (2009).
5.
Y. Toker, V. Prabhudesai, I. Rahinov, M. L. Rappaport, O. Heber, D. Schwalm, D.
Strasser, U. Even, and D. Zajfman.,
Magic Number Shift in SF6 Based Clusters.
6.
Wolfgang Christen, Klaus Rademann and Uzi Even.,
Supersonic beams at high particle densities:Model description beyond the ideal gas
approximation.
■ Chemical Physics
Dr. Oded Hod
Doctoral Students
Dana Krepel
Masters Students
Itai Leven
Research projects
Nanoscience
and nanotechnology open a unique
opportunity for the application of highly accurate theories
to realistic material science problems. The study
research in my group focuses on the theoretical of the
mechanical,
electronic,
magnetic,
and
transport
properties of systems at the nanoscale. Using firstprinciples computational methods, we aim to characterize both ground state and dynamical
properties of such systems. A combination of codes developed
within
our
group
and
commercial
computational
chemistry
packages, operating on a highly parallelizable high-performance
computer cluster, allows us to address the properties and
functionality of a variety of systems ranging from carefully tailored
molecular structures up to bulk systems. On top of basic science
questions, the design of technologically applicable nanoscale
material properties for future applications in fields such as nanoelectronics, nano-spintronics, accurate and sensitive chemical sensing, and nano-mechanical
devices, is being pursued.
Selected projects:
Silicon nanowires and nanotubes – We are investigating the electronic and mechanical
properties of ultra-narrow silicon nanowires (SiNWs) and
nanotubes (SiNTs). The energetic stability of SiNWs grown
along different crystallographic directions is studied. The
effect of chemical doping, such as fluorine passivation, on
the electronic properties of the systems is investigated in
order to identify and characterize possible routes to control
and tailor the electronic functionality of these systems. The project is performed in
collaboration with Prof. Fernando Patolsky.
Boron Notride Nanotubes – The electro-mechanical properties of multiwalled boron-nitride nanotubes (BNNTs) are being studied. These
systems have unique properties in the sense that each layer has a
Young's modulus similar to that of carbon nanotubes, yet the interlayer
coupling is much stronger due to the polarized nature of the BN bond.
The strong interlayer coupling is expected to considerably increase the
Q-factor of nanoscale oscillators based on these molecules allowing them to serve as key
components in future Nano Electro-Mechanical Systems (NEMS). The project is performed in
collaboration with Prof. Ernesto Joselevich from the Weizmann Institute.
Graphene Based Ultra Sensitive Chemical Sensors – The electronic response of graphene
nanoribbons to the chemisorption of external molecular species is investigated. We aim to
investigate the sensitivity, specificity, selectivity, and reliability of these systems as chemical
sensors. The project relies on the recently developed density functional theory divide-andconquer approach and its extensions to two and three dimensions. A combination of the divide
and conquer approach along with heavily parallelizable computations will allow us to perform
large scale electronic transport calculations.
Hot Phonons Generation in Graphene Nanoribbons – In collaboration with Dr. Yoram
Selzer, we are investigating the heating of phonons in graphene nanoribbons under external
bias voltage. By extending a previously published theory, a one-dimensional Boltzmann
equation code was written and used to study the dynamics and steady-state properties of heat
dissipation and phonon heating in these systems. Careful comparison with experimental
results is expected to allow the characterization of important physical parameters of these
systems. The model is being expanded to two dimensions in order to better capture the
physics involved in the transport properties through quasi-two-dimensional graphene
nanoribbons.
Equipment
Computational cluster – Our 24 node computational cluster is currently the largest of its kind
at Tel-Aviv University. Each node of the cluster has 2 quad-core Xeon 2.5 GHz processors, a
total of 16GB of RAM and 1TB of disk space. All the nodes are interconnected via a 48-port
Gigabit Ethernet Switch and are mounted within a 39U tall rack. The nodes run the centos
operating system and are managed via a head node that utilizes the PBS Queuing system
that controls the job priorities. Cluster status data such as load, critical temperatures, and
security compromises are continuously monitored by the head node. During the coming year
the cluster will be considerably expanded.
Workstations – 4 workstations were purchased including an Intel Core 2 Duo E8400 3.0GHz
CPU, 4GB of RAM, and 0.5 TB of hard drive space.
Collaborators
1.
Prof. Ernesto Joselevich - Department of Materials and Interfaces, Weizmann Institute
of Science: Electromechanical properties of boron nitride nanotubes.
2.
Prof. Leeor Kronik – Department of Materials and Interfaces, Weizmann Institute of
Science: Large scale calculations of electronic transport through molecular junctions.
3.
Prof. Fernando Patolsky – School of Chemistry, Tel-Aviv University: Physical
properties of SP3 silicone nanowires and nanotubes.
4.
Prof. Yoram Selzer - School of Chemistry, Tel-Aviv University: Hot phonons in
graphene nanoribbons under externally applied electric bias.
Membership in Learned societies
Israel chemical Society
Americal Chemical Society
Research Grants
2008-2012 – Israel Science Foundation.
2009-2013 – International reintegration grant – European Union.
2010-2010 – Israeli Ministry of Defense (MAFAT).
Publications
1.
S. Hod and O. Hod,
"Analytic treatment of the black-hole bomb".
submitted (2009). arXiv:0910.0734.
2.
O. Hod and G. E. Scuseria,
"Electromechanical properties of suspended graphene nanoribbons".
Nano Letters (Letter) 9, 2619-2622 (2009).
3.
O. Hod and G. E. Scuseria,
"Half-metallic zigzag carbon nanotube dots".
ACS Nano 2, 2243-2249 (2008).
4.
O. Hod, R. Baer, and E. Rabani,
"Magneto-Resistance of Nanoscale Molecular Devices Based on Aharonov-Bohm
Interferometry".
J. Phys.: Cond. Mat. 20, 383201 (2008).
5.
N. Marom, O. Hod, G. E. Scuseria, and L. Kronik,
"Electronic Structure of Copper Phthalocyanine: a Comparative Density Functional
Theory Study"
J. Chem. Phys. 128, 164107 (2008).
6.
O. Hod, V. Barone, and G. E. Scuseria,
"Half-metallic graphene nanodots: A comprehensive first-principles theoretical
study".
Phys. Rev. B 77, 035411 (2008).
7.
G. Cohen, O. Hod, and E. Rabani,
"Constructing Spin Interference Devices from Nanometric Rings".
Phys. Rev. B 76, 235120 (2007).
8.
O. Hod, V. Barone, J. E. Peralta, and G. E. Scuseria,
"Enhanced Half-Metallicity in Edge-Oxidized Zigzag Graphene Nanoribbons".
Nano Letters (Letter) 7, 2295-2299 (2007).
9.
O. Hod, J. E. Peralta, and G. E. Scuseria,
"Edge effects in finite elongated graphene nanoribbons".
Phys. Rev. B 76, 233401 (2007).
■ Chemical Physics
Prof. Dan Huppert
Emerico Letay Chair in Chemical Processes.
Technical Staff
Naum Koifman
Doctoral Students
Rinat Gepshtein
Anna Uritski
Limor Radozkovicz
Itay Presiado
Yuval Erez
Pavel Leiderman
Liat Genosar
Masters Students
Evgeny Butovsky
Tanya Lasiza
Research Projects
1.
Solvation Dynamics
2.
Proton Transfer Reactions
3.
Proton Mobility in Ice
4.
Non Radiative Processes in Condensed Phase
Collaborations
1.
Prof. Noam Agmon, Hebrew University, Jerusalem
2.
Prof. Boris Fainberg, Holon Academic Institute of Technology, Holon...
3.
Prof. Laren M. Tolbert, Georgia Institute of Technology, Atlanta.
4.
Prof. James Remington, University of Oregon, Eugene.
5.
Dr. Giti Frie, Technion, Haifa.
6.
Prof. S. Kotlyar, Biochemistry, Tel Aviv University.
Research Grants
BNSF 2005-2009 Proton Transfer in GFP
ISF
2009-2013 Proton Mobility in Ice
Publications
1.
P.Leiderman, R.Gepshtein, Trimberov I. and D.Huppert,
Effect of temperature on excited-state proton tunnelling in wt-green fluorescence
protein.
J. Phys. Chem. B 112, 1232-1239, (2008).
2.
A.Uritski and D.Huppert,
Photoacid-Base reaction in ice via mobile L-defect.
J.Phys.Chem. A, 112, 3066-3078.(2008).
3.
A. Uritski and D. Huppert,
Excited state proton transfer in methanol doped ice in the presence of KF.
J.Phys. Chem. A, 112, 4415-4425 (2008).
4.
P.Leiderman, D.Huppert, K.M.Solntsev, S.J.Remington and L.M.Tolbert,
The effect of pressure on the excited-state of in the wild-type green fluorescence
protein.
Chem.Phys.Lett., 455,303 (2008).
5.
R.Gepshtein, P.Leiderman and D.Huppert,
The origin of the nonexponential dynamics of excited-state proton transfer in wt-green
fluorescence protein.
J.Phys Chem B , 112 , 7203-7210 (2008).
6.
A. Uritski, I. Presiado and D. Huppert,
Indication of a very large proton diffusion in ice.
J. Phys. Chem. C,112,11991-12002 (2008).
7.
R. Gepshtein, D. Huppert, I. Lubitz, N. Amdursky and A. B. Kotlyar, Radiationless
transition of G4 wires and dGMP.
J.Phys. Chem. C,112,12249-12258 (2008).
8.
L. Radozkowicz, E. Project, R. Gepshtein, E. Nachliel, D. Huppert and M. Gutman,
The effect on environment on the dynamics of proton dissociation in water, special
issue Hans Limbah.
Zeitschrift für Physikalische Chemie, 222, 1247-1262(2008).
9.
A.Uritski, I.Persiado and D.Huppert,
Indication of a very large proton diffusion in ice I h . II Fluorescence quenching of flavin
mononucleotide by proton.
J. Phys. Chem.C,112,18189-18200(2008).
10.
A. Uritski, I. Presiado and D. Huppert,
Indication of a very large proton diffusion in ice I h . III. Fluorescence quenching of 1naphtol derivatives.
J.Phys. Chem. C, 113, 959-974 (2009).
11.
I. Presiado and D. Huppert,
The flavin adenine dinucleotide photophysics in ice.
J.Phys. Chem. C.,113, 3835-3804 (2009).
12.
J.N.Henderson, R.Gepshtein, J.R.Helman , K.Kallio , D.Huppert and S.J.Remington,
Structure and mechanism of the photoactivatable green fluorescent protein.
JACS, 131, 4176-4177 (2009).
13.
A.Uritski, I.Presiado, Y.Erez, R.Gepshtein and D.Huppert,
Classification of Acids and Acidities in In Ice.
J.Phys.Chem.C ,113,7342-7354 (2009).
14.
A. Uritski, I. Prediado and D. Huppert
Measurement of large proton diffusion in methanol-doped ice by fluorescence
quenching of Riboflavin.
J.Phys.Chem.C, 113,7870-7881 (2009).
15.
M.Solntsev, E.Gould, G.Pan, G.Muller, D.Huppert and L.M.Tolbert,
Excited state proton-transfer in chiral environment chiral photoacids and their
photoisomerization.
Israel Journal of Chemistry, 49, 227-233 (2009).
16.
A. Uritski, I. Prediado, Y.Erez, R.Gepshtein and D. Huppert,
Temperature dependence of proton diffusion in Ih ice.
J.Phys.Chem.C , 113, 10285-10296 (2009).
17.
A. Uritski, I. Presiado and D. Huppert,
Isotope effect of proton/deuteron diffusion constant in ice.
Israel Journal of Chemistry 49, 235-250 (2009).
18.
A. Uritski, I. Prediado, Y.Erez, R.Gepshtein and D. Huppert,
Classification of Acids and Acidities in Ice II. Reversible photoacids as a probe for
proton concentration.
J.Phys.Chem.C, 113, 12901-12910 (2009).
19.
N. Henderson, M. Osborne, R. Gepshtein , D. Huppert and S.J. Remington,
Excited-state pt in the red fluorescence protein mKeima.
JACS, 131, 13212-13213 (2009).
20.
A. Uritski, I. Prediado, Y.Erez, R.Gepshtein and D. Huppert,
Unusual Temperature Dependence of the Proton Transfer rate from 8- hydroxy- 1,3,6pyrene Trisulfonate Photoacid to the methanol-doped ice.
J.Phys .Chem. C, 113, 17915-17926 (2009).
21.
I. Presiado, Y. Erez, R. Gepshtein and D. Huppert,
Excited-state proton transfer and proton reactions of 6-hydroxyquinoline and
hydroxyquinoline in water and I h ice.
J.Phys .Chem .C, 113, 20066-20075 (2009).
7-
22.
N.Amdursky, R.Orbach, D.Huppert and E.Gazit,
Probing the inner cavities of hydrogels by proton diffusion.
J. Phys. Chem. C, 113, 19500-19505 (2009).
23.
L. Radozkowicz, D. Huppert, E. Nachliel, and M. Gutman,
The mechanism of folding of FAD in water-methanol solutions through Molecular
Dynamics combined with fluorescence measurements.
J. Phys. Chem. B.. Accepted for publication
■ Chemical Physics
Prof. Joshua Jortner
http://www.tau.ac. il/chemistry/jortner
Technical Staff
Dr. Israel Schek
Research Staff
Dr. Isidore Last
Research Projects
1.
Exploration of the phenomena of energy acquisition, storage and disposal in isolated
molecules, clusters, condensed phases and biophysical systems.
2.
Radiationless transitions in isolated large molecules.
3.
Energetics, spectroscopy and dynamics of clusters and nanostructures
4.
Relaxation processes in condensed phases.
5.
Electronic states and transport in molecular crystals, disordered materials and
biopolymers.
6.
Electron transfer in chemistry and biology.
7.
Dynamic processes in biophysics.
8.
Ultrafast processes in chemistry and biology.
9.
Ultraintense laser-matter interaction.
10.
Ultracold finite systems.
Collaborations
1.
Professor Vlasta Bonacic-Koutecky, The Humboldt University, Berlin.
2.
Professor Ludger Wöste, Physics Department, The Free University of Berlin.
Science Policy
1.
Past President of the Israel National Academy of Sciences and Humanities.
2.
Founding President of the Israel Science Foundation.
3.
Past President of the International Union of Pure and Applied Chemistry.
4.
Member of the Board of the Dan David Prize.
5.
Member of the Board of the Cyprus Research and Education Foundation.
Editorial Boards
1.
Theoretical Chimica Acta.
2.
Laser Chemistry.
3.
Chemical Physics.
4.
Russian Journal of Chemistry.
5.
Honorary Member of Physical Chemistry Chemical Physics Board.
Membership in Learned Societies
1.
Member of the Israel National Academy of Sciences and Humanities.
2.
Member of the International Academy of Quantum Molecular Science.
3.
Foreign Member of the American Philosophical Society.
4.
Member of the Royal Danish Academy of Sciences and Letters.
5.
Foreign Honorary Member of the American Academy of Arts and Sciences.
6.
Foreign Member of the Polish Academy of Sciences.
7.
Honorary Member of the Romanian Academy of Sciences.
8.
Member of the Academia Scientiarum et Artium Europaea (European
Academy of Sciences and Arts).
9.
Foreign Member of the Russian Academy of Sciences.
10.
Member of the Deutsche Akademie der Naturforscher Leopoldina.
11.
Foreign Fellow of the Indian National Science Academy.
12.
Foreign Associate of the National Academy of Sciences of the United States
of America.
13.
Foreign Member of the Royal Netherlands Academy of Arts and Sciences.
14.
Foreign Fellow of the Learned Czech Society.
15.
Fellow of the Royal Society of Chemistry.
Research Grants
2003-2009
DNA-based Nanoelectronic Devices
2005-2012
The James Franck Program in Laser Matter Interaction
Publications
Articles
1.
With I. Last,
Nucleosynthesis Driven by Coulomb Explosion within a Single Nanodroplet.
Phys. Rev. A 77, 033201-1 – 033201-8 (2008).
2.
With A. Heidenreich and I. Last,
Nanoplasma Dynamics in Xe Clusters Driven by Ultraintense Laser Fields.
Eur. Phys. J. D 46, 195-202 (2008).
3.
With A. Aharoni, D. Oron, U. Banin and E. Rabani,
Long-Range Electron to Vibrational Energy Transfer in Nanocrystals.
Phys. Rev. Letts. 100, 057404-1 – 057404-4 (2008).
3a . Selected for February 18, 2008, issue of the Virtual Journal of Nanoscale Science
& Technology.
4.
With I. Last,
Scaled Molecular Dynamics Simulations for Ultraintense Laser-Cluster Interactions.
Polish Journal of Chemistry 80, 661-673 (2008).
5.
With F. Peano, J.L. Martins, R.A. Fonseca, F. Peinetti, R. Mulas, G. Coppa, I. Last and
L.O. Silva,
Expansion of Nanoplasmas and Laser-Driven Nuclear Fusion in Single Exploding
Clusters.
Plasma Phys. Control. Fusion 50, 124049-124056 (2008).
6.
With A. Heidenreich and I. Last,
Extreme Dynamics and Energetics of Coulomb Explosion of Xe Clusters
Phys.Chem.Chem.Phys 11, 111-124 (2009).
Cover Article for the Centennial Issue of the Journal.
7.
With I. Last, F. Peano and L.O. Silva,
dt Nuclear Fusion within a Single Coulomb Exploding Composite Nanodroplet.
Eur. Phys. J. D 54, 71-75 (2009).
Cover Article for the Special Issue Commemorating the Centennial of the Journal.
8.
With I. Last, F. Peano and L.O. Silva,
Two-Pulse Driving of dd Nuclear Fusion within a Single Coulomb Exploding
Nanodroplet.
Physics of Plasmas (in press, 2010).
9.
With I. Last, F. Peano, and L.O. Silva,
Overrun Effects in Nuclear Fusion within a Single Coulomb Exploding Nanodroplet.
Eur. Phys. J. D (in press 2010).
■ Chemical Physics
Prof. (Emeritus) Uzi Kaldor
The Emerico Letay Chair in Quantum Chemistry
Academic Staff
Dr. Ephraim Eliav
Post- Doctoral Fellow
Dr. Miroslav Ilias
Doctoral Students
Anastasia Borschevsky
Hana Yakobi
Igor Itkin
Masters Students
Tamar Zelovich
Research Projects
1.
Structure and properties of heavy and super-heavy atoms.
2.
Properties of quantum dots.
3.
Relativistic effects on atoms and molecules.
4.
Multi-reference coupled cluster methods.
5.
The intermediate Hamiltonian and extrapolated IH methods.
6.
Quadrupole moments of heavy elements
Membership in Learned Societies
1.
American Physical Society
2.
Israeli Chemical Society
Publications
1.
V. Pershina, A. Borschevsky, E. Eliav, and U. Kaldor,
"Prediction of the behavior of elements 112 and 114 on inert surfaces from ab
initio Dirac-Coulomb atomic calculations"
J. Chem. Phys. 128, 024707 (2008).
2.
D. Figgen, A. Wedig, H. Stoll, M. Dolg, E. Eliav, and U. Kaldor,
"On the Performance of Two-Component Energy-Consistent Pseudopotentials
in Atomic Fock-Space Coupled Cluster Calculations".
J. Chem. Phys. 128, 024106 (2008).
3.
V. Pershina, A. Borschevsky, E. Eliav, and U. Kaldor,
"Adsorption of Inert Gases, Including Element 118, on Noble Metal and Inert
Surfaces from ab initio Dirac-Coulomb Calculations".
J. Chem. Phys. 119, 144106 (2008).
4.
V. Pershina, A. Borschevsky, E. Eliav, and U. Kaldor,
"Prediction of Atomic Properties of Element 113 and its Adsorption on Inert
Surfaces from ab initio Dirac-Coulomb Calculations".
J. Phys. Chem. 112, 13712 (2008).
5.
H. Yakobi, E. Eliav, and U. Kaldor,
"The nuclear Quadrupole Moment of 69Ga and 115In",
Can. J. Chem. 87, 802 (2009).
6.
E. Eliav, A. Borschevsky, K. R. Shamasundar, S. Pal, and U. Kaldor,
"Intermediate Hamiltonian Hilbert Space Coupled Cluster Method: Theory and
Pilot Application".
Intern. J. Quantum Chem. 109, 2909 (2009).
7.
A. Borschevsky, V. Pershina, E. Eliav, and U. Kaldor,
"Electron Affinity of Element 114, with comparison to Sn and Pb",
Chem. Phys. Lett. 480, 49 (2009).
■ Chemical Physics
Prof. Joseph Klafter
Heinemann Chair of Physical Chemistry
Chairman of the Academic Board of the Israel Science Foundation (2002-2009).
President, Tel Aviv University
Post- Doctoral Students
Alessandro Taloni
Sebastian Weber
Doctoral Students
Ariel Lubelsky
Tal Koren
Ronen Berkovich
Shlomi Reuveni
Yasmine Meroz
Research Projects
A few research directions are investigated in the group:
• Anomalous kinetics
• Energy transfer and light harvesting
• Nanotribology
• Fractional transport equations
• Levy noise
• Dynamics of single biomolecules
• Deviations from simple diffusion and exponential relaxation are widespread in physics and
chemistry and are referred to as strange kinetics. Characteristic to strange kinetics and
subdiffusive and superdiffusive behaviors which can be understood in terms of the
relatively new concepts of Levy processes and fractional calculus.
• The concept of Levy walks, introduced by us, generalizes the known Brownian motion to
include anomalous diffusion. Properties of these stochastic processes and application to
nonlinear systems are investigated. Complimentary to the Levy walk approach are
fractional kinetic equations. Since anomalous diffusion has been established in a broad
spectrum of complex systems, modifications of the traditional kinetic equations (FokkerPlanck and Langevin) are needed. We investigate the Langevin equation with a broad Levy
noise, and the fractional Fokker-Planck equation. The latter has been recently applied for
single molecule studies in biology.
• Energy transfer and reaction mechanisms in supermolecules such as dendrimers are
investigated, following our suggestion to use these tree-like molecules for light harvesting.
Random walk approaches and calculations of first passage times are applied in order to
formulate the problem.
• The "text book" concepts of friction are being revisited in light of the recent experimental
results. Methods of controlling friction are introduced. The research involves topics in
nonlinear dynamics such as control of chaos and theories of confined molecular systems.
• We introduced a new approach to build microscopic engines on the atomic scale that move
translationally or rotationally and can perform useful functions such as pulling of a cargo.
Characteristic of these engines is the possibility to determine dynamically the directionality
of the motion. Further properties and the possibility to synthesize such engines are
explored.
• The fluctuations of single molecules around equilibrium and their catalytic activity have
been investigated in collaboration with experimental groups. The Michaelis - Menten
scheme has been revisited and a modified scheme has been suggested. We introduced a
fractal model to describe the fluctuation of single proteins.
Current Collaborations
1.
Prof. A. Blumen, University of Freiburg, Germany
2.
Prof. I. Sokolov, Humboldt university, Germany
3.
Prof. O. Chechkin, Kharkov, Ukraine
4.
Prof. R. Metzler, Nordita, Denmark
5.
Dr. G. Oshanin, University of Paris VI, France
6.
Prof. A.E. Filippov, Donetsk, Ukraine
7.
Dr. I. Eliazar, Tel Aviv University
8.
The group of Prof. F.C. de Schryver, Leuven, Belgium
9.
The group of Prof. R.J.M. Nolte, Nijmegen, the Netherlands
10.
Prof. R. Granek, Ben Gurion University
11.
Dr. O. Benichou, University of Paris VI, France
12.
Prof. A. Weron,Wroclaw,Poland
13.
Dr. M. Ma,Wroclaw,Poland
Scientific Committees
1.
Member (observer) in the European Science Foundation, PESC committee.
2.
Chairman of the Academic Board of the Israel Science Foundation 2002-2009
Conference Committees
International Program Advisory Committee - of ICL'08, the 15th International
1.
Conference on Luminescence and Optical Spectroscopy of Condensed
Matter.
2.
International Advisory Board 5th International Conference on Broadband
Dielectric Spectroscopy And Its Applications
Editorial Boards
1.
International Journal of Modern Physics B
2.
Israel Journal of Chemistry
3.
Journal of Physical Chemistry (1994-1999)
5.
Journal of Luminescence
6.
Journal of Statistical Physics
Membership in Learned Societies
Israel Chemical Society
1.
2.
American Physical Society, USA.
3.
Material Research Society, USA.
4.
American Chemical Society, USA.
Research Grants
2008
ISF
2009
DIP
Prizes and Fellowships
1993 Fellow of the APS
1996 Humboldt Research Award
1999 Weizmann Prize for Sciences
2003 Kolthoff Prize
2004 Rothschild Prize in Chemistry
2005
2009
2009
Israel Chemical Society Prize
Fellow of the Freiburg Institute for Advanced Studies
Honorary Doctorate, Wroclaw University of Technology
Publications
1.
R. Berkovich, J. Klafter and M. Urbakh,
Analyzing friction forces with the Jarzynski equality .
J. Phys. Cond. Matter 20, 354008 (2008).
2.
A. Lubelski and J. Klafter ,
Fluorescence recovery after photobleaching: The case of anomalous diffusion
Biophys. J. 94, 4646-4653 (2008).
3.
M. A. Lomholt, Tal Koren, Ralf Metzler and J. Klafter,
Levy Strategies in intermittent search processes are advantageous.
PNAS 105, 11055-11059 (2008).
4.
A. Lubelski and J. Klafter
Temporal Correlation Functions of concentration fluctuations: An anomalous
case.
J. Phys. Chem. B 112, 12740-12747 (2008).
5
I. Eliazar and J. Klafter
The Oligarchic structure of Paretian Poisson processes.
EPL 83, 40004 (2008).
6.
A. Lubelski, I. M. Sokolov and J. Klafter,
Nonergodicity mimics Inhomogeneity in Single Particle Tracking.
Phys. Rev. Lett., 100, 250602 (2008).
7.
Z. Tshiprut, M. Urbakh and J. Klafter
Single-Molecule Pulling Experiments: When the Sttiffness of the Pulling
Device Matters.
Biophys. J. 95, L42-L44 (2008).
8.
S.B. Yuste, G. Oshanin, K. Lindenberg, O. benichou and J. Klafter,
Survival probability of a particle in a sea of mobile traps: A tale of tails
Phys. Rev. E. 78, 021105, Part 1(2008).
9.
I. Eliazar and J. Klafter,
Fractal Poisson processes.
Physica A 387, 4985-4996 (2008).
10.
I. Eliazar and J. Klafter,
Fractal probability laws.
Phys. Rev. E. 77, 061125 (2008).
11.
Marcin Magdziarz, Aleksander Weron and J. Klafter,
Equivalence of the Fractional Fokker-Planck and subordinated Langevin
equations: The case of time-dependent force.
Phys. Rev. Lett. 101, 210601 (2008).
12.
I. Eliazar and J. Klafter,
Statistical resilience of random populations to random perturbations.
Phys. Rev. E. 79, 011103 (2009).
13.
I. Eliazar and J. Klafter
Power-Law Distributions: Beyond Paretian Fractality,
Risk and Decisions Analysis. 1, 155-170 (2009)
14.
I. Eliazar and J. Klafter,
The maximal process of nonlinear shot noise.
Physica A 388, 1755-1779 (2009).
15.
I. Eliazar and J. Klafter,
From Ornstein-Uhlenbeck dynamics to long-memory processes and
fractional Brownian motion.
Phys. Rev. E. 79, 021115 (2009).
16.
H. Wolfenson, A. Lubelski, T. Regev, Y. I. Henis, B. Geiger and J. Klafter,
A Role for the Juxtamembrane Cytoplasm in the Molecular Dynamics of
Focal Adhesions.
PloS One 4, e4304 (2009).
17.
I. Eliazar and J. Klafter,
On the generation of anomalous diffusion.
J. Phys. A 42, 472003 (2009).
18.
Y. Meroz, I. Eliazar and J. Klafter,
Facilitated diffusion in a crowded environment: from kinetics to stochastics.
J. Phys. A 42, 434012 (2009).
19.
M. de Leeuw, S. Reuveni and J. Klafter et. Al.,
Coexistence of flexibility and stability of proteins: An equation of state.
PloS One 4, e7296 (2009).
20.
I. Eliazar and J. Klafter,
Universal generation of statistical self-similarity: A randomized central limit
theorem.
Phys. Rev. Lett. 103, 040602 (2009).
21.
I. Eliazar and J. Klafter,
A unified and universal explanation for Levy laws and 1/f noises.
PNAS 106, 12251-12254 (2009).
22.
A. Lubelski and J. Klafter,
Fluorescense correlation spectroscopy (FCS): The case of subdiffusion
Biophys. J. 96, 2055-2063 (2009).
■ Chemical Physics
Prof. Gil Markovich
http://www.tau.ac.il/~gilgroup
Doctoral Students
Nurit Taub
Daniel Szwarcman
Daniel Azulai
Olga Krichevsky
Tal Meron
Gabriel Shemer
Einat Tirosh
Masters Students
Ben Maoz
Boris Tsukerman
Tatyana Belenkova
Hagit Gilon
Amir Hevroni
Assaf Ben Moshe
Sigalit Bechler
Tom Shachar
Itai Lieberman
Lola Brown
Research Projects
1.
Growth and alignment of metal nanorods and nanowires on surfaces.
2.
Preparation of 2D ordered magnetic nanoparticle arrays and studies of their
magnetic properties.
3.
Electron transport in magnetic nanoparticle arrays –magneto-resistive
properties.
4.
Magnetic and magneto-optical properties of nanocrystals made of new
magnetic
materials,
such
as
Mn
doped
ZnO
and
defect
induced
ferromagnetism in HfO 2 and MgO.
5.
Scanning probe studies of single- and arrays of magnetic nanocrystals.
6.
Studies of the interactions of chiral molecules with surface plasmon
excitations of noble metal nanoparticles.
7.
Preparation and studies of the properties of ferroelectric nanocrystals
Collaborations
1.
Prof. Sara Majetich, Carnegie-Mellon University
2.
Prof. Hannes Lichte, Dresden University
3.
Prof. Alexander Kotlyar, TAU
4.
Prof. Edward Kosower, TAU
Membership in Learned Societies
1.
Israel Chemical Society
2.
American Chemical Society
3.
Materials Research Society
Research Grants
2006-2010
Israel Science Foundation, “Controlling the composition of complex
oxide nanocrystals: From chemistry to magnetism”
2007-2011
US-Israel
Binational
Science
Foundation,
“Arrays
of
strongly
interacting magnetic nanoparticles – “watching” a phase transition with
spatial and temporal resolution”
2007-2010
Converging Technologies grant (by ISF), "Merging Plasmonics with
Chiral
Bio-molecules:
Plasmon
Enhanced
Circular
Dichroism
Spectroscopy"
2009-1012
German-Israeli Foundation, "Exploring nanoscale ferroelectricity in
isolated and interacting ferroelectric nanocrystals using electron
holography"
Publications
Articles
1.
I. Lieberman, G. Shemer, T. Fried, E. M. Kosower, G. Markovich,
“Plasmon Resonance Enhanced Absorption and Circular Dichroism”.
Angew. Chem. Int. Ed. 47, 4855-4857 (2008).
2.
E. Tirosh, N. Taub, S. A. Majetich, G. Markovich,
"Scanning Tunneling Spectroscopy study of Temperature Dependent
Magnetization Switching Dynamics in Magnetic Nanoparticle Arrays".
Isr. J Chem. 48, 81-86 (2008).
3.
N. Taub, A. Tsukernik, G. Markovich,
"Inter-particle Spin Polarized Tunneling in Nano-devices of Magnetite
Nanocrystals".
J. Mag. Mag. Mater. 321, 1933-1938 (2009).
4.
A. Heyman, I. Medalsy, O. Dgany, D. Porath, G. Markovich, O. Shoseyov,
"Float and Compress: A Honeycomb like Array of a Highly Stable Protein
Scaffold".
Langmuir 25, 5226 (2009).
5.
A. Dror-Ehre, H. Mamane, T. Belenkova, G. Markovich, A. Adin,
"Silver nanoparticle–E. coli colloidal interaction in water and effect on E. coli
survival".
J. Colloid Interface Sci. 339, 521-526 (2009).
6.
D. Azulai, T. Belenkova, H. Gilon, Z. Barkay, G. Markovich,
"Transparent metal nanowire thin films prepared in mesostructured
templates".
Nano Lett. 9, 4246-4249 (2009).
P
P
Abstracts and Posters in Conferences
1.
"Metal Nanoparticle plasmons interacting with chiral molecules" ,Particles
2008, Orlando FL (May 2008).
2.
"Magnetization Dynamics of Strongly Interacting Magnetic Nanocrystals
Stduied by STM", Gordon Research Conference on Magnetic Nanostructures,
Aussois, France (Septemebr 2008).
3.
"Size Dependent Ferroelectric Polarization in BaTiO 3 Nanocrystals Probed by
R
R
Electron Holography" ,Material Research Society meeting, San Francisco CA,
(April 2009).
4.
"Plasmon Resonance Enhanced Absorption and Circular Dichroism ",
Molecular Plasmonics, Jena, Germany (May 2009).
5.
"Plasmon resonance enhanced absorption and circular dichroism in metal
nanoparticles capped with chiral molecules" ,American Chemical Society
meeting, Washington DC (August 2009).
■ Chemical Physics
Prof. Abraham Nitzan
The Iser and Rivka Kodez Chair in Chemical Dynamics
Post-Doctoral Fellows
Dr. Josef Subotnik
9T
Dr. Dhurba Rai
Dr. Agostino Migliore
Dr. Philip Schiff
Dr. Guangqi Li
Doctoral Students
Vered Ben Moshe
9T
Inon Sharoni
9T
Michal Oren
9T
Research Areas
1
Theoretical studies of activation, relaxation and energy transfer processes in molecular
systems.
2.
Transport phenomena in condensed phases and at interfaces.
3.
Theory of chemical reaction rates in condensed phases.
4.
Ionic diffusion and conductivity in solid ionic conductors, in polymers and in confined
Systems.
5.
Electromagnetic and electronic interactions in small particles and clusters.
6.
Theoretical investigations of charge transfer and charge separation phenomena in
condensed phases, interfaces and nano-systems.
7.
Molecular electronics.
8.
Numerical simulations of relaxation and transport processes.
9.
Numerical simulations of quantum mechanical processes.
Editorial Boards
1.
Computational and Theoretical Nanoscience
2.
Physical Review Letters
3.
Journal of Chemical Physics
Research Grants
1.
2006-2008 Israel Science Foundation "Manifestations of strong lectronicvibrational coupling in molecular conduction”.
2.
2006-2008 US-Israel BSF "Computational and theoretical studies of
lectron transport in molecular conduction junctions".
3.
4.
2008-2013 ISF Focus Center :”Molecular Control of Electronic and Magnetic
Properties of Interfaces.”
5.
2009-2012 US-Israel BSF: “Optical response, characterization and control of
molecular conduction junctions”.
6.
2008-2013 ERC : “Thermal, optical and redox processes in molecular conduction
junctions”.
7.
2008-2011 Israel - Niedersachsen research collaboration: “Multiple charge transfer
and transport in molecular systems".
8.
2008-2009 Kurt Lion Fund: “Charge Transport in restricted Geometries.
Publications
1.
M. Galperin, M.A. Ratner and A. Nitzan,
Heat conduction in molecular transport junctions.
Phys. Rev. B 75, 155312 (2007).
2.
M. Galperin, M.A. Ratner and A. Nitzan,
Molecular Transport Junctions: Vibrational Effects.
J. Phys.: Condens. Matter 19, 103201 (2007).
3.
M. Galperin, M.A. Ratner and A. Nitzan,
Inelastic effects in molecular junctions in the Coulomb and Kondo regimes:
Nonequilibrium equation-of-motion approach.
Phys. Rev. B 76, 035301 (2007).
4.
A. Landau, L. Kronik and A. Nitzan,
Cooperative effects in molecular conduction.
J. Comp. Theor. Nanoscience, 5, 535-544 (2008).
15T
15T
5.
15T
A. Nitzan,
Molecules take the heat (Perspective).
Science, 317, 759-760 (2007).
6.
M. Galperin, M.A. Ratner, A. Nitzan,
Inelastic effects in molecular junction transport: Scattering and self-consistent
calculations for the Seebeck coefficient.
Molecular Physics, 106, 397-404 (2008).
7.
B.Fainberg,M.Jouravlevand A. Nitzan ,
Theory of light-induced current in molecular-tunneling junctions excited with intense
shaped pulses.
Phys. Rev. B 76, 245329 (2007) .
8.
M. Galperin, M.A. Ratner, A. Nitzan and A. Troisi,
Nuclear Coupling and Polarization in Molecular Transport Junctions: Beyond
Tunneling to Function.
Science, 319, 1056-1060 (2008).
9.
Joseph
E. Subotnik,
A. Nitzan,
2006-2009
Germany-Israel
(GIF) "Dynamical phenomena in electron
Multibody Scattering, Correlation, Molecular Conduction and the 0.7 Anomaly.
transport through molecular wires" .
J. Chem. Phys. 129, 144107 (2008).
10.
M. Galperin, A. Nitzan and M. A. Ratner,
Inelastic transport in the Coulomb blockade regime within a nonequilibrium atomic limit.
Phys. Rev. B, 78, 125320 (2008).
11.
M. Galperin, A. Nitzan and M. A. Ratner,
The non-linear response of molecular junctions: the polaron model revisited.
J. Phys.: Condens. Matter 20, 374107 (2008) .
12.
B. Fainberg and A. Nitzan,
Decaying Rabi oscillations in quantum-dot tunnelling junctions.
Phys. Stat. Sol. A, 206, 948-951 (2009).
13.
4T
S. S. Skourtis, D. N. Beratan, R. Naaman, A. Nitzan and D. H. Waldeck,
Chiral control of electron transmission through molecules.
Phys. Rev. Letters, 101, 238103 (2008).
[Science Perspective by R. J. Cave: Science, 323, 1435 (2009)]
4T13
4T13
4T13
4T13
4T13
14.
S. Tornow, R. Bulla, F. B. Anders and A. Nitzan,
Dissipative two-electron transfer: A numerical renormalization group study.
Phys. Rev. B 78, 035434 (2008).
15.
M. Galperin, M.A. Ratner and A. Nitzan,
Raman scattering from non-equilibrium molecular conduction junctions.
Nano Letters, 9, 758-762 (2009).
16.
M. Galperin, M.A. Ratner and A. Nitzan,
Raman scattering in current carrying molecular junctions.
J. Chem. Phys. 130, 144109 (2009) .
17.
S. Yeganeh, M. Ratner M. Galperin and A. Nitzan,
Transport in State Space: Voltage-Dependent
Benzene-1,4-dithiol.
Nano Letters, 9, 1970-74 (2009).
15T
18.
Conductance
Calculations
A. Landau, L. Kronik and A. Nitzan,
Cooperative effects in molecular conduction II: The Semiconductor −Metal
Molecular Junction.
J. Phys. Chem. A, 113, 7452-7460 (2009).
of
19.
M. Galperin, K. Saito, Al. V. Balatsky and A. Nitzan,
Cooling mechanisms in molecular conduction junctions.
Phys. Rev. B 80, 115427 (2009).
20.
J. E. Subotnik, T. Hansen, M. A. Ratner and A. Nitzan,
Nonequilibrium steady state transport via the reduced density matrix operator.
J. Chem. Phys. 130, 144105 (2009).
21.
H. Nakanishi, K. J. M. Bishop, B. Kowalczyk, A. Nitzan, E. A. Weiss, K. V.
Tretiakov, M. M. Apodaca, R. Klajn, J. F. Stoddart and B. A. Grzybowski,
Photoconductance and inverse photoconductance in films of functionalized metal
nanoparticles.
Nature, 460, 371-375 (2009).
In Press
M. Einax, M. Körner, P Maass and A. Nitzan
Nonlinear hopping transport in ring systems and open channels
Chemical Physics.
■ Chemical Physics
Prof. Eran Rabani
Head, Department of Chemical
Physics
Post-Doctoral Students
Dr. Shimon Saraf
Doctoral Students
Avi Ben-Simon
Guy Cohen
Sagi Eppel
Tal Levy
Orly Kletenik-Edelman
Claudia Vartash-Sztrum
Masters Students
Guy Cohen
Yotam Hakim
Research Projects
Multiexciton Generation in Nanocrystals:
Multiexciton generation (MEG) is a process
where several excitons are generated upon
the
absorption
semiconductors.
of
a
MEG
single
is
of
photon
in
potential
significance for improving the efficiency of
light harvesting devices, such as solar cells.
Strict
selection
rules
and
competing
processes in the bulk allow generation of
multiexcitons at energies of 5 times the band
Figure 1: Multiexciton generation path ways.
gap. It was suggested that nanocrystals, where quantum confinement effects are important,
may exhibit MEG at lower values of energy.
We have recently developed a theory to
understand the processes of multiexciton generation in semiconducting nanocrystals. The
nanocrystal electronic structure was described using our screened pseudopotential method
known to give reliable description of the excitons. The rates of multiexciton generation were
calculated using Fermi’s golden rule with all relevant Coulomb matrix elements taking into
account proper selection rules. In CdSe, InAs and Si nanocrystals we find a broad distribution
multiexciton generation rates depending strongly on the exciton energy and size of the
nanocrystals. The broad distribution gives rise to average multiexciton generation rates that
are too slow to occur in energies below 3 times the band gap.
In fact, we argue that
multiexciton generation in the bulk for these materials is more efficient than in nanocrystals.
Energy transfer at the nanoscale: The development of novel sensing, imaging, and
biological labeling is an expanding research field in recent years. In particular, fluorescence
probes are widely used in single molecule imaging1 and spectroscopy, and in the detection
techniques of proteins, peptides, and enzymes. Early studies were based mainly on organic
dye molecules as fluorophores. However, since organic dyes have very broad emission lines
and fast photobleaching, their
applications
More
are
recently,
quite
limited.
semiconductor
nanocrystal quantum dots have
been
suggested
as
potential
fluorophores. In this context, we
have developed a theory for the
fluorescence resonance energy
transfer (FRET) between a pair of
Figure 2: Energy transfer between two nanoparticles.
semiconducting nanocrystal quantum dots. The theory relies on a simple effective mass
model which is used to relate the FRET rate to measurable quantities such as the nanocrystal
size, fundamental gap, effective mass, exciton radius and dielectric constant. The relative
contribution to the FRET rate of the different multipole terms, the role of strong to weak
confinement limits, and the effects of nanocrystals sizes were addressed.
Conductance in low-dimensional structures: Another important direction that we have
been involved in recent years is related to the development of feasible nanometric
magnetoresistance devices. We
have a good understanding of
the role of magnetic fields in
micrometric devices, and the
interplay
between
weak
to
strong localization effects has
been studied in depth. What
about
similar
Figure 3: Conduction as a function of gate and magnetic flux in a
nanometric three terminal molecular device.
systems? A naive calculation would lead one to assume that unphysical huge magnetic fields
are required to magnetically switch a nanometer device. Recently, we have shown ways to
overcome this difficulty. The basic idea is to create narrow tunneling resonances through a
molecular ring-like structure that are highly sensitive to the magnetic field. We have described
computational methods that allowed us to examine atomistic models of such systems and
discussed several specific examples of plausible systems, such as the quantum corral, carbon
nanotubes, and polycyclic aromatic hydrocarbon molecules. Similarly to the electric gate, the
magnetic field provides means to externally control the conductance of a ring-shaped
molecular junction. We find that there are striking differences in the properties of these two
gauges. This was illustrated for a multi-terminal device, where the polarity of the magnetic
field, which couples to the electronic angular momentum, played a key role. More recently we
showed that there is also a fundamental difference with respect to inelastic effects. While the
conductance as a function of the gate voltage broadens upon coupling to phonons, it actually
narrows considerably in response to a magnetic field. This unexpected result was rationalized
in terms of a rapid loss of the phase of electrons at the exit channel arising from the coupling
to the phonons.
Figure 4: Schematics of the Anderson impurity model.
The second direction, triggered by the fascinating results described for inelastic effects in
molecular interferometers, involves the development of a new approach to calculate the
current in molecular junction where many-body effects such as electron-electron or electronphonon interactions are important. Our approach is based on a real-time propagation of the
many-body density matrix using real-time quantum Monte Carlo techniques. We have applied
the approach to the Holstein model and provided the first exact numerical solution.
In
addition, we have also applied the real time path integral approach to the Anderson impurity
model and currently we are at the stage of providing a full time-dependent numerical solution
to the Kondo problem.
Structure of nanomaterials: We have also been involved in the development of atomistic
models to study structural properties of semiconductor nanocrystals and carbon nanotubes. In
many situations, the characterization of the structural properties of these materials is not
feasible experimentally, and a theoretical approach is required. We were the first to develop
an atomistic force-field model for semiconductor nanocrystals and studied the structural
properties of the interface between the inorganic core and the organic passivation layer. The
model was used to explain the coverage of the different facets of the nanocrystal and the
resulting preferential growth of nanocrystals to nanorods. Recently, we have studied the sixto-four fold pressure induced phase transformation
in CdSe nanocrystals using the atomistic model
described above. We have identified a novel
mechanism for the six-to-four fold transformation,
which does not exist in bulk CdSe, and proceeded
via a 5-fold h-MgO intermediate structure. Our
prediction awaits experimental verification.
Figure 4: Pressure induced phase
transformation mechanism in CdSe
nanocrystals.
Collaborators
1.
Prof. Roi Baer, Institute of Chemistry, The Hebrew University. Conductance in
nanosystems.
2.
Prof. Uri Banin, Institute of Chemistry, The Hebrew University. Self-assembly and
metal/semiconducting heterostructures.
3.
Prof. Joshua Jortner, School of Chemistry, Tel Aviv University. Quantum clusters.
4.
Prof. David R. Reichman, Department of Chemistry, Columbia University. Dynamics in
quantum liquids and glasses.
5.
Dr. Roy Shenhar, Institute of Chemistry, The Hebrew University. Hierarchical selfassembly of nanoparticles.
Memberships in Learned Societies
1.
Israel Chemical Society
2.
American Chemical Society
3.
American Physics Society
4.
Associate Member of Working Party on Computational Chemistry
Honors and Awards
1.
J.T. Oden Faculty Fellow, University of Texas, Austin 2009.
2.
Visiting Professor, Ecole Normale Superieure, Paris 2008-2009.
3.
The Michael Bruno Memorial Award, Yad Hanadiv, 2006-2009.
Research Grants
1.
2003-2007: United States-Israel Binational Science Foundation.
2.
2005-2008: Sixth Framework Programme – Specific Targeted Research Project
3.
2006-2009: Ministry of Science.
4.
2007-2008: Department of Defense – AFRL.
5.
2007-2011: Israel Science Foundation.
6.
2007-2010: Converging Technologies of the ISF.
7.
2008-2012: Israel Science Foundation.
Publications
1.
O. Kletenik-Edelman, E. Ploshnik, A. Salant, R. Shenhar, U. Banin, and E. Rabani,
“Drying-Mediated Hierarchical Self-Assembly of Nanoparticles: A Dynamical CoarseGrained Approach”.
J. Phys. Chem. C 112, 4498-4506. (2008).
2.
L. Mühlbacher and E. Rabani,
“Real-Time Path Integral Approach to Nonequilibrium Many-Body Quantum Systems”.
Phys. Rev. Lett. 100, 176403 (2008).
3.
A. Aharoni, D. Oron, U. Banin, E. Rabani, and J. Jortner,
“Long-Range Electronic to Vibratioal Energy Transfer in Nanocrystals”.
Phys. Rev. Lett. 100, 057404 (2008).
4.
5.
G. Cohen and E. Rabani,
“Negative Differential Spin Conductance by Population Switching”,
Mol. Phys. 106, 341-347 (2008).
R. Baer and E. Rabani,
“Theory of Resonance Energy Transfer Involving Nanocrystals: The Role of High
Multipoles”.
J. Chem. Phys. 128, 184710 (2008).
6.
O. Hod, R. Baer and E. Rabani,
“Magneto-Resistance of Nanoscale Molecular Devices Based on Aharonov-Bohm
Interferometry” (invited).
J. Phys.: Cond. Mat. 20, 383201 (2008).
7.
E. Rabani and R. Baer,
“Distribution of carrier multiplication rates in CdSe and InAs nanocrystals.
Nano. Lett. 8, 4488-4492 (2008).
8.
O. Kletenik-Edelman, C.G. Sztrum-Vartash, and E. Rabani,
“Coarse-Grained Models for Self-Assembly of Nanomaterials”,
J. Mater Chem. 19, 2872-2876 (2009).
9.
R. Costi, G. Cohen, A. Salant, E. Rabani and U. Banin,
“Electrostatic Force Microscopy study of Single Au-CdSe Hybrid Nanodumbbells :
Evidence for Light Induced Charge Separation”.
Nano. Lett. 9, 2031-2039, (2009).
10.
D.R. Reichman and E. Rabani,
“Analytic Continuation Average Spectrum Method for Quantum Liquids”.
J. Chem. Phys. 131, 054502 (2009).
11.
O. Kletenik-Edelman, E. Rabani, and D.R. Reichman,
“Analytic continuation average spectrum method for transport in quantum liquids.”
Chem. Phys., submitted (2009).
■ Chemical Physics
Dr. Yael Roichman
Doctoral Students
Kfir Gil
Maya Yavnin
Masters Students
Adar Sonn
Tal Maya
Yulia Sokolov
Roi Rutenberg
David Kapfenberger
Research Projects
Research in soft condensed matter is concerned with materials whose basic units consist of
mesoscopic building blocks. Examples include complex fluids such as biological gels,
emulsions, polymer solutions, and colloidal suspensions, as well as granular materials. Some
of these systems are studied for their interesting statistical mechanics properties whereas
others are studied as model system for a broader class of materials.
There is also a close connection between biology and soft condensed matter physics. The
constituents of living tissues – protein, DNA, cells and cellular membranes – are complex
fluids. Biological systems also provide a rich setting for exploring many fundamental issues in
nonequilibrium statistical mechanics.
Some of our current projects are listed below:
•
Faceting and growth of droplets on micro-fabricated surfaces
We look at the problem of morphology selection in faceting and roughening of quasicrystals in
equilibrium, which is virtually uncharted territory. To this aim we use an analog system of
liquid spreading on a textured landscape. Our aim in this ongoing study is to understand how
the symmetry, scale and composition of the patterned substrate govern droplet spreading,
shrinking, and translation. As part of this effort, we explore the influence of substrate
symmetry on hydrophobicity, with potential applications for self-cleaning surfaces and antibacterial coatings.
•
Limit Cycles and Chaos on Optical Vortexes.
Hydrodynamic interaction between colloidal particles are usually of little importance in self
assembly under quasi-equilibrium conditions, however, they could play an important role in
assembling structures in a driven system. In order to improve our understanding of the effect
hydrodynamic interactions have on directed self assembly we study a simple drivendissipative system of colloids confined to move on a ring.
Surprisingly, we find that hydrodynamic interactions lead these systems to exhibit behaviors
ranging from periodic motion to intermittent motion to chaotic motion depending on
temperature. Moreover, it seems that the diffusion of a single particle in the ensamble of
rotating colloids is anomalous.
•
Active microrheology as a probe for cell mechanics.
Complex fluid usually respond non-linearly to applied forces. It is becoming increasingly clear
that this non-linear behavior is used by the cell to transmit mechanical signals along its
backbone. Due to its economic use of samples and non-destructive nature, microrheology
has emerged as a desired tool to study cell mechanics. The viscoelastic properties of the
investigated materials are inferred from the motion of a tracer particle in that media. However,
microrheology is restricted to work in the linear regime since its analysis is based on linear
response.
We believe that knowing the nonlinear elasticity of the cell skeleton will lead to better
understanding of mechanotrunsduction. To this end, we intend to extend microrheology by
using holographic optical tweezers to drive the tracer particles and measure the non-linear
response of the materials. We will develop a proper analysis tool for these systems by
comparing bulk measurements to active and passive microscopic measurements.
•
Imaging of antibiotic modes of action.
Biochemical processes are usually studied using indirect measurements due to the small
scale of the participating components, namely, molecules. Recent advances in fluorescent
imaging extend our ability to see down to the single molecule scale. Using video microscopy
and innovating optical imaging, we intend to reexamine the different mode of action in which
antibiotics attack living bacteria. Adding quantitative kinetic information on the process
dynamics we hope to better our understanding of these processes, leading to new insights
and better implementation of antibiotics.
Collaboration
1.
Paul Chakin and David Grier, New York University and Dov Levine, Technion-Israel
Institute of Technology . Wetting and faceting in quasicrystalline textured surfaces.
2.
Anne Bernheim, Ben Gurion University. Mechanics of active actin networks.
3.
Haim Diamant, Tel Aviv University. Statistical mechanics of driven colloidal
suspensions.
4.
Michael Fridman, Tel Aviv University. Imaging of bacterial demise.
Membership in Learned Societies
1.
Israel Chemical Society
2.
Israel Physical Society
3.
American Physical Society
4.
Optical Society of America
Research Grants
2008-2011
Yigal Alon Fellowship, Israeli Council for Higher Education
2008-2009
Converging Technologies grant, integration grant
2008-2012
Israel Science Foundation, Universality in system far from thermal
equilibrium: from microscopic to macroscopic behavior.
2008-2009
Israel Science Foundation, Holographic optical tweezers in the IR and green.
2009-2013
Marie Curie International Reintegration Grants, Active microrheology for
probing stress transmission in complex media
2009-2013
US-Israel Binational Science Foundation, Faceting and roughening: the effects
of disorder and quasicrystallinity