Poster Session A
Monday, February 13, 2017
1
PA-1
Enhancing the Stability and Selectivity of Nanocarriers by Dimerization of
their Building Blocks
Ido Rosenbaum, Roey J. Amir
Organic Chemistry, Tel Aviv University, Tel Aviv, Israel
Enzyme-responsive micelles have a great potential as drug delivery systems due to the high selectivity and
overexpression of disease-associated enzymes. Recently we have reported on enzyme-responsive amphiphilic
block copolymers composed of a hydrophilic PEG block and a dendron with enzymatically cleavable lipophilic
end-groups as the hydrophobic block. These amphiphilic hybrids formed micellar structures in aqueous
environment and enzymatic activation led to their disassembly. However, when examining micelles and their
properties, it is clear that one of the biggest challenges is the the risk of their fast dilution and disassembly in
the body. By cross-linking the micelles we can increase their stability and decrease their spontaneous
disassembly in the body. By choosing a reversible cross-linker such as disulfide bonds, we will also benefit the
introduction of another stimuli-responsive group. This will open the way for smart nanocarriers with improved
micellar stabilities that require activation by both types of stimuli for their disassembly.
Keywords:
Block copolymer micelles, Enzyme responsive materials, Nanocarriers.
2
PA-2
Proof of Hydrogen Spillover by Product-Distribution Analysis in Solid Phase
Hydrogenations
Adi Mary Akiva Moyal1,2, Ofra Paz-Tal1, Eyal Ben-Yehuda1, Michael Gozin2,
Svetlana Pevzner1
1
Chemistry Department, Nuclear Research Centre Negev, Beer-Sheva, Israel
2
School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
Hydrogenation in the solid-phase is important in green-chemistry for the limited use of solvents and use of
solid, recyclable catalysts and, in the field of hydrogen-scavenging, preventing risks of explosion, or hydrogeninduced metal corrosion or embrittlement.
In solid-phase hydrogenations the reaction progress is believed to involve hydrogen-spillover, where the
activated hydrogen migrates across the catalyst’s carbon-support. The study of solid-phase hydrogenation of
1,4-bis(phenylethynyl)benzene (PEB) was used to demonstrate the effect of different parameters on the solidphase hydrogenation mechanism.
The samples of PEB containing a Pd/C catalyst were hydrogenated to various degrees at different initial
pressures and with the addition of carbon-nanotubes (CNTs) or C60 fullerenes; the partially hydrogenated
samples were then analyzed by gas-chromatography, for product quantification.
Comparison of the products distribution at different reaction-conditions gives insight into the nature of the
spillover-mechanism of hydrogenation in the solid-phase.
The results of this study show that the product-distribution is greatly affected by the hydrogen pressure.
Addition of CNTs, known to accelerate solid-phase hydrogenations, gives the same effect on productdistribution trend as a hydrogen pressure increase. We suppose that CNTs facilitate and increase the distance of
the hydrogen’s migration from the metal catalyst to the substrate.
C60 addition has the opposite effect. The reaction-rate substantially diminishes; and the product-distribution
trend resembles that of decreased hydrogen pressure. We suppose that the mechanism of C60 inhibition is by
recombination of hydrogen-atoms into molecular hydrogen and subsequent H2 release to the gas-phase. Thus,
we can presume that the nature of the spilled-over hydrogen is radical.
In summary, by studying the product-distribution of the solid-phase hydrogenation at different pressures with
the addition of additives, we gain insight into the reaction mechanism.
3
PA-3
Facile and Highly Chemoselective N-Difluoromethylation of Functionalized
Tertiary Amines
Dafna Amir, Lea Yehezkel, Naama Karton-Lifshin, Moran Madmon, Sigal Saphier,
Eytan Gershonov, Yossi Zafrani
Organic Chemistry, Israel Institute for Biological Research, Ness-Ziona, Israel
Synthesis of organic compounds containing fluorine atoms has become one of the more important issues in the
field of organic synthesis because of the central role fluorinated functions play as bioisosteres in agrochemicals
and drugs, leading to changes in affinity, metabolic stability, hydrophobicity and bioavailability of various
bioactive compounds. In the world of organic synthesis, the incorporation of a fluorine atom/s is also frequently
employed for various other applications to modify both chemical and physical properties of molecules. Among
various fluorinated moieties, difluoromethyl (-CF2H) is one of the most promising. Quaternary ammonium salts
are a well-known and abundant family of compounds used in medical applications, cosmetics, agriculture, and
chemical catalysis. Since the charged moiety is responsible for the unique properties of these compounds, the
influence of a difluoromethyl group adjacent to the cationic center may be of interest. In this work, we present a
practical, convenient and general method for the difluoromethylation of tertiary amines, using diethyl
bromodifluoromethylphosphonate and fluoride. We found that this commercially available phosphonate
smoothly reacts with a fluoride ion to liberate a difluorocarbene intermediate that in the presence of a proton
source and a tertiary amine generates the corresponding a-difluoromethyl ammonium compound in good to
excellent yields. Despite the involvement of a difluorocarbene intermediate, this difluoromethylation occurs
almost exclusively on the nitrogen atom with diverse molecular structures (e.g. drugs, ionic liquids, polymers).
Combining the two highly important issues of fluorinated organic compounds and quaternary ammonium salts
may lead to interesting changes in chemical and physical properties. A preliminary assessment of the effects an
a-difluoromethyl group has on hydrogen bonding and log P of quaternary ammonium salts is also described.
4
PA-4
Design and Synthesis of Highly Branched Organocatalysts
for Site–Selective Acylation
Natali Ashush, Ramesh Palakuri, Moshe Portnoy
School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences,
Tel Aviv University, Tel Aviv, Israel
Site-selective acylation organocatalysts are a promising approach for preparing derivatives of polyhydroxylated
natural products. Working toward this goal, we synthesized a molecular probe for acylation reaction that
includes two reactive sites, which are situated in different environment (polar and a-polar). Such design allows
examining the tendency of various catalysts to perform acylation at a specific site (Scheme 1).
We envisaged using the dendritic architecture in order to create a catalytic pocket of a specified polarity. Thus,
we conceived a catalytic system composed of a dendrimer that incorporates a polar imidazole active site in the
interior and an a-polar periphery that will create a hydrophobic envelopment of this catalytic site. We presume
that the polarity differences between the dendrimer regions will impact the probe access path into the catalytic
pocket and, consequently, allow a preferred reaction at a particular site.
The designed catalysts (Figure 1) were synthesized, examined under several standard sets of conditions and
compared to a simple non-dendritic analogue. The catalytic experiments revealed several trends, reflecting the
effects of the probe concentration, solvent polarity and the nature of the acylation reagent. Based on these
findings, preference for the desired site of the proe can be achieved by providing specific conditions and a
specific catalyst.
5
PA-5
Enzymatically Degradable Self-Reporting Micelles
Marina Buzhor, Roey J. Amir
Department of Organic Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv,
Israel
Enzyme responsive micelles have gained increased interest in recent years due to their high potential in
different field`s ranging from smart materials to drug delivery. Our group has recently developed a highly
modular platform of enzymatically degradable polymeric micelles. These micelles are composed of selfassembled amphiphilic hybrids of hydrophilic polyethyleneglycol (PEG) block and a dendron functionalized
with enzymatically cleavable hydrophobic end-groups. The need for new methods for drug delivery and
imaging probes led us to develop the next generation of labeled smart micelles that can self-report their
structural changes by spectral response. Here we present a novel design of covalently labeled enzymeresponsive amphiphilic hybrids that can report the self-assembly and disassembly of the micelles by changes in
the dyes` spectral properties. These spectral changes occur due to alteration of dye-dye interactions caused by
the supramolecular structural changes of the micelles. By simply changing the labeling dyes, we demonstrate
different spectral activities (turn-On or spectral-switch of the spectral signal [1]) that are generated due to
different dye-dye interactions, such as, excimer formation, self-quenching or FRET. This highly modular
approach opens the way for new delivery platforms that allow advanced methods for imaging and tracking the
degree and location of drug released.
[1] “Supramolecular translation of enzymatically triggered disassembly of micelles into tunable
fluorescent responses”, Buzhor, Marina; Harnoy, Assaf J.; Tirosh, Einat; Barak, Ayana; Schwartz, Tal; Amir,
Roey J. Chemistry–A European Journal 21.44 (2015): 15633-15638.
6
PA-6
Metal-free Catalytic Chlorination of Silanes and Silylation of Ethers
Karina Chulsky, Roman Dobrovetsky
Chemistry, Tel Aviv University, Tel Aviv, Israel
Silyl chlorides play an important role in organic synthesis, they are used to protect hydroxyl functional groups.
They are also important precursors in organosilicon chemistry and are used for the synthesis of branched
organosilanes and sol-gel materials. Various procedures were developed for chlorination of silanes, however,
most of these methods suffer from poor selectivity and the use of toxic materials. Herein we present a new
selective method for Lewis acid (B(C6F5)3) catalyzed chlorination of silanes by HCl. In addition, we developed
a B(C6F5)3 catalyzed method for activation of ethers in presence of silanes, forming silylethers and
corresponding alkanes. This method can be potentially used to replace a very robust alkyl ethereal protecting
groups to more labile silyl protecting group, this chemistry is currently under investigation. Detailed protocols,
the most recent results and the mechanisms supported both by experiment and by theoretical calculations are
shown.
7
PA-7
Thioxobimanes: Structural and Chelating Studies
Partha J. Das1, Ankana Roy1, Yael Diskin-Posner2, Iddo Pinkas2, Ashim Nandi3,
Sebastian Kozuch3, Michael Firer4, Michael Montag1, Flavio Grynszpan1
1
Department of Chemical Sciences, Ariel University, Ariel, Israel
2
Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
3
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
4
Department of Chemical Engineering and Biotechnology, Ariel University, Ariel, Israel
syn-(Me,Me)Bimane (1) bears the heterocyclic molecular core of a well-known class of biologically relevant
fluorescent dyes. Despite their intrinsic characteristics as chelating agents (O-donors and sterically available π
system) the coordination chemistry of bimanes has not been explored. Recently, we reported the first example
of a cationic Pd(II) complex containing syn-(Me,Me)bimane as an O-donor chelating ligand.[1]
In order to expand the scope of bimanes by accessing derivatives with different chelating and fluorescence
properties while keeping the low number of atoms in their basic structure, we reasoned that the carbonyl
oxygen atoms could be replaced by sulfur ones. We applied traditional thionating chemistry (Lawesson’s
reagent and P4S10) in the preparation of syn-monothioxobimane (2), syn-dithioxobimane (3) and antidithioxobimane (4). Our preliminary results indicate that the introduction of sulfur atoms to the bimane core
results in significant depression of the original fluorescence intensity, in the UV-vis region.
X-ray data and computational quantum mechanical modeling methods were used to shed light on the topology
and dynamics of the bimane core structure. Our latest results describing syn-thioxobimanes as ligands in metal
complexes as well as their structural and spectroscopic implications will be presented.
[1] Das, P. J.; Diskin-Posner, Y.; Firer, M.; Montag, M.; Grynszpan, F., Dalton Trans. 2016, 45, 17123-17131.
8
PA-8
Olefination of N-Sulfinylimines under Mild Conditions
Shubhendu Dhara, Charles E. Diesendruck
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
Olefins are ubiquitous building blocks in many naturally occurring bioactive molecules and important reactive
intermediates in numerous organic transformations.1A plethora of organic transformations have been invented
for the stereo-controlled construction of substituted alkenes.2 Importantly, new approaches for the synthesis of
olefins are still being investigated, as transformation of different functional groups into olefins may be key in
the total synthesis of natural compounds, drugs etc. Sulfinyl groups have an important role as chiral auxiliaries
in nucleophilic addition reactions. Therefore, N-sulfinylimines have been attracting much interest owing to their
simple preparation and inherent reactivity. Here, we demonstrate a simple and efficient diastereoselective
transformation of this chiral directing group into useful 1,2-disubstituted alkenes, which can be further
functionalized as required. Different aryl phosphonates reacted with a range of electronically diverse Nsulfinylimines to afford in greater than 99:1 E-alkenes in almost every case. The most important feature of this
protocol is that the reaction can be performed at room temperature using inexpensive sodium hydride as the
most effective base to generate the reactive phosphonate ylide producing E- alkenes in high yields.
Reference:
1)Comprehensive Natural Products Chemistry, vol. 1–9 (Eds.: D. Barton, K. Nakanishi), Elsevier, New York,
1999.
2)Williams, J. M. J. Preparation of Alkenes: A Practical Approach; Oxford University Press: Oxford, UK,
1996. (c) Kelly, S. E. In ComprehensiVe Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon: Oxford,
UK, 1991; Vol. 1, p 729.
9
PA-9
Asymmetric Copper-Catalyzed Carbomagnesiation of Cyclopropenes
Longyang Dian, Daniel S. Müller, Ilan Marek
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
In the last few years, we have been interested in the selective ring-opening of cyclopropanes for the preparation
of quaternary carbon stereocenter in acyclic systems.1 However, for this approach to be reliable and efficient,
one needs to have an easy access to the preparation of diastereo- and enantiomerically enriched polysubstituted
cyclopropanes from a common and easily accessible precursor. In this context and in continuation of our
previous effort on the preparation of diastereo and enantiomerically enriched polysubstituted cyclopropanes, 2
we demonstrate herein a highly enantio- and diastereoselective Cu-catalyzed carbomagnesiation reaction of
unfunctionalized cyclopropenes with a great variety of alkyl Grignard reagents. The flexibility and easily
availability of both partners (cyclopropenes and Grignard reagents) provide a novel, mild and convenient
approach to a variety of polysubstituted cyclopropanes. The carbometalated species generated in situ readily
undergo C-C and C-X bond forming reactions with various electrophiles with retention of configuration.
Reference:
[1] For our recent works on the C-C bond cleavage of cyclopropanes, see: a) S. Simaan, I. Marek, J. Am. Chem.
Soc. 2010, 132, 4066; b) P.-O. Delaye, D. Didier, I. Marek, Angew. Chem. Int. Ed. 2013, 52, 5333; c) A.
Masarwa, D. Didier, T. Zabrodski, M. Schinkel, L. Ackermann, I. Marek, Nature 2014, 505, 199; d) A.
Vasseur, L. Perrin, O. Eisenstein, I. Marek, Chem. Sci. 2015, 6, 2770; e) A. Masarwa, D. Gerbig, L. O., A.
Loewenstein, H. P. Reisenauer, P. Lesot, P. R. Schreiner, I. Marek, Angew. Chem. Int. Ed. 2015, 54, 13106; f)
M. Simaan, P.-O. Delaye, M. Shi, I. Marek, Angew. Chem. Int. Ed. 2015, 54, 12345; g) S. R. Roy, D. Didier, A.
Kleiner, I. Marek, Chem. Sci. 2016, 7, 5989; h) F.-G. Zhang, G. Eppe, I. Marek, Angew. Chem. Int. Ed. 2016,
55, 714.
[2] D. S. Müller, I. Marek, J. Am. Chem. Soc. 2015, 137, 15414. For previous works on the asymmetric
carbozincation of cyclopropens by other groups, see: b) M. Nakamura, A. Hirai, E. Nakamura, J. Am. Chem.
Soc. 2000, 122, 978; c) K. Krämer, P. Leong, M. Lautens, Org. Lett. 2011, 13, 819.
10
PA-10
Selective Synthesis of Polyaryls by Iron Catalyzed Consecutive Oxidative
Cross-Coupling of biphenols
Alina Dyadyuk, Vlada Vershinin
Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
An Iron catalysed consecutive oxidative cross-coupling reactions between single biphenolic units and
nucleophilic arenes is presented, offering a direct entry to complex phenolic oligomers. The direct impact of
different types of substituents on each phenol ring of the biphenolic unit on the reaction regioselectivity (ortho,
para or meta) and chemoselectivity (C-coupling or O-coupling) was examined.
References:
1] Alina Dyadyuk, Kavitha Sudheendran, Yulia Vainer, Vlada Vershinin, Alexander I. Shames and
Doron Pappo, Lett.,2016, 18 (17), pp 4324–4327
2] Eden Gaster, Yulia Vainer, Almog Regev, Sachin Narute, Kavitha Sudheendran, Aviya Werbeloff,
Hadas Shalit, and Doron Pappo, Chem. Int.Ed., 2015, 54, pp 4198 –4202
3] Anna Libman, Hadas Shalit, Yulia Vainer, Sachin Narute, Sebastian Kozuch, and Doron Pappo, Am.
Chem. Soc.,2015, 137 (35), pp 11453–11460
11
PA-11
Tuning Mechanical and Thermomechanical Properties by Intramolecular
Cross-Linking
Or Galant, Feng Wang, Charles E. Diesendruck
Shulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
The thermomechanical response of a solid polymer is a function of the forces between the polymer chains,
which, above the entanglement limit, depends almost exclusively on the monomer chemistry. In this research,
we exploit intramolecular cross-links to physically limit entanglement between chains and study the effect of
the thermomechanical and mechanical properties independently of the monomer chemistry. The synthetic
strategy involves a two-step approach; first a linear chain is prepared; then, intramolecular cross-linking is
carried out under high dilution to inhibit intermolecular reactions. In my research, I have been using RAFT
polymerization to prepare a linear random copolymer containing a mixture of methyl methacrylate (MMA) and
(2-acetoacetoxy) ethyl methacrylate (AEMA). Cross-linking is performed by Michael addition using
trimethylolpropane triacrylate as the Michael acceptor.[1] This project expands the possibilities in bottom-up
materials design, in which the architecture of the polymer chains on the nanoscale is specifically tailored
towards desired final material properties. This research will lead to a better understanding of how polymer
architecture, in addition to chemistry, affects the form and entanglement of chains, and therefore solid-state
bulk thermomechanical and mechanical properties.
[1] “Michael” Nanocarriers Mimicking Transient-Binding Disordered. Ana Sanchez-Sanchez, Somayeh
Akbari. ACS Macro Letters, p. 2013.
12
PA-12
Direct Selective Aerobic Catalyzed Oxidation of Methylarenes to
Benzaldehyde Derivatives in HFIP as Hydrogen Bond Donor Medium
Eden Gaster, Doron Pappo
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
Hydrogen Bond Donor (HBD) medium can be used to control reaction selectivity by stabilizing Hydrogen
Bond Acceptor (HBA) products. This concept is applied in the aerobic catalyzed Co(II)/N-Hydroxyphthalimide
(NHPI) oxidation of methylarenes to selectively form benzaldehyde derivatives at ambient temperature with no
trace of benzoic acid using 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP) as the reaction medium.
13
PA-13
Stimuli-responsive Self-immolative Chemiluminescent Polymers
Samer Gnaim, Doron Shabat
Organic Chemistry, Tel Aviv University, Tel Aviv, Israel
Molecular probes based on 3-hydroxyphenyl-1,2-dioxetane chemiluminescence light emission are widely used
for various sensing and diagnostic applications (e.g., DNA, enzymatic and chemical probes). Amplification of
molecular signals is an important task for the development of sensitive diagnostic probes in the field of
chemical sensing. Recently, various approaches have been introduced to increase the signal-to-noise ratio of
chemiluminescent light emission as a molecular signal.
This work describes the design and synthesis of a new class of self-immolative chemiluminescent polymers
constructed of four complementary components: ) chemically stable 1,2-dioxatene analog incorporated an
adamantyl group (bulky substituent), ii) protected 4-hydroxybenzyl alcohol substituent (self-immolative
monomeric linker), iii) a chemical or biological responsive group (e.g., silyl protecting group), and iv) the
monomers are linked together via carbonate linkage.
Our results show that a single cleavage event of the protecting group on the phenol results in the formation of a
quinone derivative of 1,2-dioxetane, which undergoes a rapid 1,6-elimination to release the leaving group on
the benzyl alcohol. A nucleophilic attack on the benzylic-methide position initiates a chemically initiated
electron-exchange luminescence (CIEEL) process affording methyl benzoate and light emission.
Using this new class of chemiluminescent polymers introduce the ability to design a novel stimuli responsive
chemilumnescent polymers as an amplification systems.
14
PA-14
The Effect of H2 on AgOTf Catalyzed Transformations of Aldehydes
Yael Gottlieb, Roman Dobrovetsky
Organic Chemistry, Tel Aviv University, Tel Aviv, Israel
The ability to perform different chemical transformations on a molecule using the same catalyst just by varying
reaction conditions is a great challenge in synthetic organic chemistry. We report here that the reaction of
aldehydes with a catalytic amount of AgOTf leads to trimerization products (trioxanes). Interestingly, when the
same reaction is performed under 4 atmospheres of H2, the reaction changes its course and leads to aldol
condensation products. We believe that in AgOTf catalyzed aldehyde trimerization process, AgOTf acts as a
Lewis acid. However, when H2 is added to the reaction mixture, heterolytic cleavage of H2 takes place, leading
to the formation of H+ (Bronsted acid) species that selectively catalyze the aldol condensation reaction. The
mechanism, supported by DFT calculations, for these transformations is proposed.
15
PA-15
Synthesis and Catalytic Activity of Dicationic Zn Complexes
Kristina Groutchik, Arseni Kostenko, Roman Dobrovetsky
Organic Chemistry, Tel Aviv University, Tel Aviv, Israel
Hydrogenation and hydroelementation of C=E bonds (E = O, N, C) are among the most important organic
reactions. Most catalytic methods involve the use of noble transition metal-based catalysts, which are
expensive, scarce or toxic. Hence, the focus of today’s research is their replacement by cheaper and less toxic
transition metal-free catalysts. The use of zinc in this perspective is of a great interest, because of its abundance,
biological relevance and distinct abilities. Here we report the synthesis of dicationic Zn complexes embedded in
tri and tetra dentate ligands, and their use in catalysis. By changing the ligand`s strategic centers we will able to
fine-tune the properties of zinc center i.e. its Lewis acidity, which will have a direct impact on the reactivity and
catalytic activity of these new Zn-based compounds.
16
PA-16
Structure and Activity of Ikarugamycin Derivatives Isolated from the Extracts
of Actinomyctes Bacteria Cultures
Ohad Hasin1, Ohad Hasin1, Dhaneesha Mohandas2, Sajeevan Thavarool2, Shmuel Carmeli1
1
Raymond and Beverly Sackler School of Chemistry and Faculty of Exact Sciences,
Tel Aviv University, Tel Aviv, Israel
2
National Centre for Aquatic Animal Health, Cochin University of Science and Technology,
Cochin, India
As part of our continues study on marine derived organisms and bacteria we studied the extracts of marine
Actinomyctes. Four natural products, presenting cytotoxic properties, were isolated from extracts of the
Streptomyces sp. MCCB267 cultures. The cells were freeze-dried, extracted with ethyl acetate and separated by
different chromatographic methods, including Sephadex LH-20 and HPLC chromatography. The anticancer
activity of the extracts were screened during the purification process against the NCI - H460 Lung cancer Cell
line using Sulforhodamine B (SRB) assay. The structure of the isolated compounds was determined by analysis
of the 1D and 2D NMR spectra, high-resolution mass spectroscopy, UV spectra, IR spectra and optic rotation
(αD). Ikarugamycin and 28-N-methyl ikarugamycin were isolated from samples DMS-21, DMA-37-WD and
DMA-37-D. 30-oxo-28-N-methyl ikarugamycin and clifednamide A were isolated from sample DMS-21. The
structure elucidation and biological activity of the compounds will be presented.
17
PA-17
Aminomethylene-Phosphonate Analogues as Zn(II)-Chelators: Synthesis and
Characterization
Thomas Jantz, Bosmat Levi Hevroni, Hugo Gottlieb, Bilha Fischer
Department of Chemistry, Bar-Ilan University, Ramat-Gan, Israel
series of aminomethylene(ethylene)-phosphonate (AMP, 1, AEP, 2) analogues, 3-9, bearing one or two
eterocyclic moieties (imidazolyl, pyridyl, and thiazolyl) on the aminomethylene group, were synthesized
aspotential agents for Zn(II)-chelation therapy. The complexes of analogues 3-9 with Zn(II)-ions were
characterized by their stoichiometry, geometry, coordination-sites, acid-base equilibria, and stability constants.
Analogues 3-9 form stable water-soluble 2:1 L:Zn(II) complexes, as established by Zn(II)-titration, monitored
by UV and by 1H- and 31P-NMR spectroscopy. Acidity and stability constants were established for each
derivative by potentiometric pH-titrations. ML2-type Zn(II)-complexes of AMP, bearing either an imidazolyl or
pyridyl moiety, 3, 4, and 5, exhibit high log values – 17.68, 16.92, and 16.65, respectively, while for the
AMP-thiazolyl, 6, -Zn(II) complex, log is 12.53. Generally, ligands 7, 8, and 9, bearing two heterocyclic
moieties, present higher log values (22.25, 21.00, and 18.28, respectively) vs. analogues bearing one
heterocyclic moiety. Additionally, based on 1H-,13C-, and 31P-NMR data, we propose a structure of AMP(Im)2-Zn(II) complex in solution, where the Zn(II)-coordination sites involve the phosphonate moiety and
both imidazolyl rings of the two binding molecules, forming an octahedral geometry around the Zn(II)ion. In summary, we propose a novel family of water-soluble high-affinity Zn(II)-chelators, potentially
useful for Zn(II)-chelation therapy, and in particular we suggest using AMP-(Im)2.
18
PA-18
Synthesis, Characterization and Reactivity of Thermally Stable Anhydrous
Quaternary Ammonium Fluorides
Naama Karton-Lifshin, Lea Yehezkel, Nissan Ashkenazi, Ishay Columbus, Shlomi Elias,
Yossi Zafrani
Organic Chemistry, Israel Institute for Biological Research, Ness-Ziona, Israel
Anhydrous Quaternary ammonium fluorides have been widely documented as very strong nucleophiles/bases
and are of significant interest in inorganic and organic synthesis. However, when trying to prepare such
compounds by hydrate removal conditions (heating under dynamic vacuum), they show instability and easily
undergo Hoffmann elimination (E2) by the fluoride counter ion. For example, anhydrous TBAF decomposes
even at room temperature, and therefore, it can only be prepared and used “in situ” at low temperatures. The
present work describes the synthesis and properties of a new class of anhydrous quaternary ammonium
fluorides based on the rigid skeleton of [2.2.2] azabicyclooctane, in which the Hoffmann elimination is
structurally prevented even at temperatures up to 120oC. Four such structures were easily prepared by passing
the corresponding ammonium iodides over a fluoride-based resin followed by drying under heating and reduced
pressure. The stability (experimental and theoretical study), solubility, reactivity and characterization by
solution and solid-state MAS NMR are discussed.
19
PA-19
Ru‑Catalyzed Chelation-Assisted Alkenylation of Heteroatom Substituted
Aromatics and Heteroaromatics with Alkenes and Alkynes
1
Kishor Padala1, Masilamani Jeganmohan2
Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
2
Department of Chemistry, IISER-Pune, Pune, India
Transition-metal-catalyzed chelation-assisted ortho C‑ H bond activation of hetero-atom substituted aromatic
followed by alkenylation with alkenes or alkynes is one of the powerful methods for synthesizing di- and
trisubstituted alkene derivatives in a highly regio- and stereoselective manner.1 It is important to mention that
the alkene derivatives found widespread application in organic materials, natural products and drug molecules.
The selection of directing group is highly important in order to success this type of alkenylation reaction. While
the C‑ H bond activation reaction in the presence of strong directing groups is well documented in the
literature. But, activation in the presence of weak directing groups such as aldehydes, esters, cyano, sulfoxide
and ketones are still a challenging task.
In this presentation, we would like to discuss a ruthenium‑ catalyzed ortho-alkenylation of hetero-atom
substituted aromatics such as aromatics and heteroaromatic carbonyl compounds with alkenes. In the reaction,
we have prepared disubstituted alkene derivatives in a highly regio- and stereoselective manner.2a-c It is
interesting to note that this catalytic reaction was conducted under the air atmosphere and only catalytic amount
of terminal oxidant Cu(OAc)2 has been used, the remaining amount of copper source being reoxidized by air. In
addition, we would like to discuss a weakly coordinating S=O assisted hydroarylation of aromatic sulfoxides
with alkynes in the presence of ruthenium catalyst leading to trisubstituted alkenes in good to excellent yields in
a highly regio- and stereoselective manner.2d
References
1. (a) Arokiam, P. B.; Bruneau, C.; Dixneuf, P. H. Chem. Rev., 2012, 112, 5879. (b) Ackermann, L. Acc. Chem.
Res., 2014, 47, 281.
2. (a) Kishor, P.; Jeganmohan, M. Org. Lett. 2011, 13, 6144. (b) Kishor, P.; Jeganmohan, M. Org. Lett. 2012,
14, 1134. (c) Kishor, P.; Pimparkar, S.; Padmaja, M.; Jeganmohan, M. Chem. Commun. 2012, 48, 7140. (d)
Kishor, P.; Jeganmohan, M. Chem. Commun. 2014, in press. (e) Kishor, P.; Jeganmohan, M. Chem. Commun.
2013, 49, 9651. (g) Kishor, P.; Jeganmohan,Chem. Eur. J. 2014, 20, 4092.
20
PA-20
Synthesis and folding of Seleno-Insulin
Orit Ktorza
Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
Insulin has been the premier drug for improving the quality of life for diabetes mellitus patients. Since the early
1960s, chain A and chain B of insulin were successfully synthesized; however the recombination of these
chains to form mature native insulin remains ineffective due to the numerous non-native disulfide links, and
peptide precipitation. Many research groups have showed total chemical synthesis of fully active insulin, or
analogs that show higher stability. Our Research project proposes an alternative approach for the preparation of
human insulin analogs by substitution of pair of cysteine residues by selenocysteine, the 21st encoded amino
acid. Since it has been shown that selenium enhances the oxidative folding and diselenide bonds are more stable
that disulfide bonds, we expect to obtain an improvement of stability and recombination of the chains in higher
yields. Here we show preliminary data on our design and synthesis of seleno-insulin.
21
PA-21
Enhanced Mechanical Endurance of Internally Cross-Linked Polymers
Avishai Levy, Feng Wang, Sinai Aharonovich, Charles E. Diesendruck
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
Understanding how materials are affected by mechanical stress is central for developing novel and robust
materials with extended lifetimes. In this regard, the most fundamental process is the effect of mechanical stress
on molecules, where mechanical energy is transduced into chemical energy by scission of chemical bonds, a
process called mechanochemistry1,2. The accumulation of stress at specific locations in the polymer chain is
known mainly for two polymeric architectures - linear and cross-linked. In our research we exploit a novel
architecture in which linear polymers are intramolecularly cross-linked, forming Single Chain Polymer
Nanoparticle (SCPN). Our study shows that whereas linear polymer chains undergo fast degradation under the
influence of mechanical force, SCPNs derived from the same linear chains demonstrate high endurance. In
addition, we studied how different parameters affect the mechanical stability such as molecular weight, crosslink density and side-chain length, and with the help of ultra-high Mw polymers, are able to observe the
scission of intramolecular cross-links and therefore redirection of the mechanical force from the polymer main
chain.
(1) Caruso, M. M.; Davis, D. A.; Shen, Q.; Odom, S. A.; Sottos, N. R.; White, S. R.; Moore, J. S. Chemical
Reviews 2009, 109, 5755.
(2) May, P. A.; Moore, J. S. Chemical Society Reviews 2013, 42, 7497.
22
PA-22
Enolonium Species – Umpoled Enolates
Shimon Maksymenko1, Shlomy Arava1, Keshaba Parida1, Mark A. Iron1,3, Peter Fristrup1,2,
Alex Szpilman1, Jayprakash Kumar1
1
Ariel University, Department of Natural Sciences, Ariel, Israel
2
Technical University of Denmark, Department of Chemistry, Kgs. Lyngby, Denmark
3
Weizmann Institute of Science, Department of Chemical Research Support, Rehovot, Israel
Nature has determined the roles of chemical reagents in organic synthesis as either electrophiles or
nucleophiles. Umpolung or Polarity Reversal is a powerful concept that allows these roles to be switched
thereby enabling a much larger array of methods to assemble complex organic molecules.
Umpolung of enolates mediated by hypervalent iodine reagents has shown itself to be the method of choice for
functionalizing of carbonyl compounds. This is amply illustrated by numerous papers describing halogenations,
oxygenations, aminations, and many other applications.[1] Recently we reported the use of this concept in C-C
bond forming reactions.[2,3] These reactions are widely believed to proceed through a iodo(III)-enolate like
structure named Enolonium Species.[1] However due to their high reactivity they are difficult to characterize
and they have consequently been researched mainly through computational studies.[2,4] We have now
characterized the Enolonium Species and shown determined their structure React-IR and NMR. A particular
point of discussion in the community and a scientific challenge was to determine whether the hypervalent
iodine is attached to the O of the enolate or to the C of its keto-form. The application of the Enolonium Species
in various reactions, including chlorination, amination, enol ether coupling and allylation (including examples
that lead to the formation of quaternary carbons), will be discussed.[5]
[1] a) V. V. Zhdankin, “Hypervalent Iodine Chemistry: Preparation, Structure, and Synthetic Applications of
Polyvalent Iodine Compounds”, Wiley, 2014; b) F. V. Singh, T. Wirth in: Comprehensive Organic Synthesis,
2nd ed., Vol 7, (Eds: G. A. Molander, P. Knochel P.), Oxford: Elsevier, 2014.
[2] O. S. Shneider, E. Pisarevsky, P. Fristrup, A. M. Szpilman, Org. Lett., 2015, 17, 282.
[3] T. A. Targel, J. N. Kumar, O. S. Shneider, S. Bar, N. Fridman, S. Maximenko, A. M. Szpilman Org.
Biomol. Chem., 2015, 13, 2546.
[4] a) S. Beaulieu, C. Y. Legault, Chem. Eur. J. 2015, 21, 11206; b) P.-O. Norrby, T. B. Petersen, M.
Bielawski, B. Olofsson, Chem. Eur. J. 2010, 16, 8251.
[5] S. Arava, J. N. Kumar, S. Maksymenko, M. A. Iron, K. N. Parida, P. Fristrup, A. M. Szpilman Submitted for
Publication.
23
PA-23
Catalytic Mechanochemistry
Iris Melnik, Charles E. Diesendruck
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
Mechanochemistry is a process in which chemical reactions are driven by mechanical stress; 1 however, up to
date, mechanochemical transformations were shown to occur only on polymers.2 Importantly, some
mechanochemical transformations could be very useful in the synthesis of small molecules such as natural
products and drugs, as the mechanical force changes the energy potential of different chemical processes,
directing the reaction to different products from the ones obtained by classical thermal, electro and
photochemistry. Here, we present an approach to use semi-telechelic polymers capable of reversibly binding
small molecule substrates and induce mechanochemical transformations catalytically.
We synthesized boronic ester terminated polymers, capable of binding 1,2- or 1,3-diols reversibly through
transesterification reaction. The general catalytic reaction is depicted in Scheme 1. Mechanochemically stable
polymers a boronic acid end group (P) and a small molecule (M1-M2) containing two 1,2-diols connect to form
a mechanochemically sensitive polymer chain with the substrate at its center (P-M1-M2-P). Under
solvodynamic shear, the substrate breaks into two substances (M1 and M2) and is released by transesterification with a new substrate.
1] Philippe Lavalle, Fouzia Boulmedais, Pierre Schaaf and Loïc Jierry, Langmuir, 2016, 32(29), 7265–
7276.
2] Jun Li, Jeffrey S. Moore, Chem. Res., 2015, 48, 2181-2190.
24
PA-24
Methodology of the C(sp )-Н Bond Functionalization in the Synthesis of Novel
Imidazole Derivatives
2
Timofey Moseev1, Mikhail Varaksin1,2, Oleg Chupakhin1,2, Valery Charushin1,2
Department of Organic and Biomolecular Chemistry, Ural Federal University, Ekaterinburg,
Russia
2
Laboratory of Heterocyclic Compounds, Institute of Organic Synthesis, Ekaterinburg, Russia
1
The C(sp2)-H Functionalization methodology is known to be an atom- and stage-efficient synthetic approach
for the synthesis of novel imidazole derivatives. It has been found that cyclic aldonitrones do react with both
azoles (i,ii) and azines (iii-v) to give the novel heterocyclic systems in good yields.1-3
The synthesized imidazole derivatives are of interest as promising polymer stabilizers, free radical trapping
agents, biologically active compounds, and nitroxide radical precursors.
1] Varaksin, M.V., Utepova I.A., Chupakhin O.N., Charushin V.N. J. Org. Chem., 2012, 77, 9087.
2] Varaksin, M.V., Utepova I.A., Chupakhin. Chem. Heterocycl. Comp., 2012, 48, 1213.
3] Varaksin, M.V., Utepova I.A., Chupakhin O.N., Charushin V.N. Tetrahedron, 2015, 71, 7077.
The study was supported by the Russian Science Foundation (Project № 14-13-01177) and the Russian
Foundation for Basic Research (Project № 16-03-00958)
25
PA-25
Synthesis of Highly Functionalized Alkenylfluorides by Silver-Mediated
Fluorodestannation
1
Heiko Sommer1,2, Alois Fürstner1
Organometallic Chemistry, Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr,
Germany
2
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
The role of fluorine in synthetic and medicinal chemistry receives an ever-increasing attention as fluorine plays
a unique role in influencing the conformation, solubility, potency, permeability or degradability of small
molecules. The late-stage introduction of fluorine is of great interest as it allows the modification of complex
molecules without significantly changing the synthetic route.
In conjunction with our previously reported ruthenium-catalyzed directed trans-hydrostannation of internal
alkynes[1], an efficient method for the synthesis of highly elaborate alkenyl fluorides could be implemented
(Scheme 1).[2]
Scheme 1. Hydrostannation/fluorodestannation for the synthesis of fluoroolefins
During our studies, we developed a mild protocol that allowed us to transform a plethora of alkenylstannanes
into the corresponding fluorides while overcoming competing protodestannation.[3] Key to success is the
utilization of the non-hygroscopic salt silver(I) diphenyl phosphinate (AgDPP) as a mediator.
We applied this new protocol to the synthesis of highly functionalized, biologically relevant compounds,
consisting among others of a polyketide derivative, a peptide bioisoster and a prostaglandin derivative (Scheme
2).
Scheme 2. Selected examples of the silver-mediated fluorodestannation
Literature
[1] a) S. M. Rummelt, A. Fürstner, Angew. Chem. Int. Ed. 2014, 53, 3626-3630; b) S. M. Rummelt, K.
Radkowski, D.-A. Roşca, A. Fürstner, J. Am. Chem. Soc. 2015, 137, 5506-5519.
[2] H. Sommer, A. Fürstner, submitted manuscript, 2016.
[3] M. A. Tius, J. K. Kawakami, Tetrahedron 1995, 51, 3997-4010.
26
PA-26
Mechanisms of Reactions of Ce(III)DOTA with Radicals in Aqueous Solutions
Elad Avraham1,2, Inna Popivker1, Israel Zilbermann1,2, Eric Maimon1,2, Guy Yardeni1,
Philippe Moisy3, Laurence Berthon3, Laurent Venault3, Dan Meyerstein2,4
1
Chemistry, Nuclear Research Center Negev, Beer-Sheva, Israel
2
Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
3
Nuclear Energy Division, Radiochemistry & Processes, CEA, Bagnols-Sur-Ceze, France
4
Chemical Sciences Department and the Schlesinger Family Center for Compact Accelerators,
Radiation Sources and Applications, Ariel University, Ariel, Israel
Recent studies have shown that DOTA stabilizes thermodynamically both Ce(III) (log K= 23.4) 1 and Ce(IV)
(log K= 35.9)2, shifting cathodically the CeIV/III couple to +0.65V vs. SCE , a stabilization of ~ 13 orders of
magnitude compared to its aqueous analogue2.
As such we decided to study the reactions of Ce(III)DOTA with several radicals, oxidizing agents: .OH; .CH3;
.OOCH (given in the exact order of the redox potentials, .OH –the strongest), analyze the products –compare to
3
the reported electrochemical and chemical oxidized cerium complex.
The radicals were produced by continuous radiolysis in aqueous N2O saturated solutions (DMSO present for
.CH ; .OOCH and 50% v/v O present for .OOCH .). The spectra of the products clearly show the formation of
3
3
2
3
long lived Ce(IV)DOTA(pH dependent) species in the case of .OH and .OOCH3. In the case of peroxyl radicals
the main organic product is methanol, different of the main product of the reactions of DOTA and DyDOTA
(not redox active) with the same radical, where formaldehyde is the main product. In the case of methyl radicals
the ratio CH4/C2H6 is similar for Ce(III)DOTA, DyDOTA and DOTA indicating an H abstraction mechanism
from DOTA as the main path. Detailed data will be presented.
1] Burai et al., J.Chem.Soc.Dalton Trans. 1998, 443.
2] Y. Moiseev et al., J.Coord.Chem. 2016, 69(19),2895
27
PA-27
Expanding the Toolbox for the Synthesis of Organometallic Nanoparticles via
the Single-Chain Collapse Approach
Inbal Berkovich, Gabriel N. Lemcoff
Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
Organic nanoparticles (ONPs) prepared via the intramolecular cross-linking of single polymer chains pose
promising prospects for various applications.1-4 We have recently developed an intramolecular single chain
collapse approach for the synthesis of organometallic nanoparticles using ROMP-derived polycyclooctadiene
(PCOD) and the direct ligand exchange of Rh(I), Ir(I) and Ni(0) complexes.5-6 This methodology was further
expanded for the preparation of high MW ONPs from commercially available polybutadiene.7 Herein, the use of
commercial polyisoprene as an alternative precursor for the preparation of ONPs will be examined. In addition,
we present our current efforts towards the preparation of catalytically active Rh(II)-ONPs by the exchange of
trifluoroacetate ligands in Rh2[TFA]4 with the -COOH groups of ROMP- derived polymers.
References:
1] T. Ashai, T. Sugiyama, H. Masuhara, Acc. Chem. Res. 2008, 41, 1790-1798.
2] S. Mavila, O. Eivgi, I. Berkovich, N. G. Lemcoff, Chem. Rev. 2016, 116, 878-961
3] A. Sanchez-Sanchez, A. Arbe, J. Colmenero, J. A. Pomposo, ACS Macro Lett., 2014, 5, 439-443.
4] N.G. Lemcoff, T. A. Spurlin, A. A. Gewirth, S. C. Zimmerman, J. B. Beil, S. L. Elmer, G.
Vandeveer, J. Am. Chem. Soc. 2004, 126, 11420-11421.
5] S. Mavila, C. E. Diesendruck, S. Linde, L. Amir, R. Shikler, N.G. Lemcoff, Angew. Chem. Int. ed.
2013, 52, 5767-5770.
6] S. Mavila, I. Rozenberg, N.G. Lemcoff, Chem. Sci. 2014, 5, 4196-4203.
7] I. Berkovich, S. Mavila, O. Iliashevsky, S. Kozuch, N. G. Lemcoff, Chem. Sci. 2016, 7, 1773-1778.
28
PA-28
Jojoba Oil Olefin Metathesis: A Valuable Source for Bio-Renewable Materials
Danielle Butilkov, Gabriel N. Lemcoff
Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
Jojoba oil is a diene composed of two monounsaturated hydrocarbon chains linked by an ester moiety.
Ruthenium catalysed cross-metathesis reactions (CM) of the oil produced ADMET oligomers and hydrocarbon
by-products under various conditions.1 Both the polyester oligomers and the hydrocarbon distillates were
analysed by several analytical techniques. The oligomers were also hydrolysed under basic conditions to assess
potential degradability. Oligomerisation of the starting material by an alternative thiol-ene ‘click’ reaction was
also probed. A high atom economy is expected for this catalytic process given that all products obtained may be
used either as sources for bio-fuel (hydrocarbons), or as potential renewable and degradable materials
(polyester chains). In addition, a novel methodology for a concise preparation of synthetic jojoba oil will be
presented.
Cyclic alkyl amino carbene (CAAC) ligands are a class of σ-donor ligands which was introduced first by
Bertrand et al. in 2005.2 Ruthenium catalysts bearing this type of ligands showed high reactivity towards
ethenolysis3 (TON = 340,000) and CM4 (TON = 315,000) reactions. Reactions of Jojoba oil and CAAC bearing
ruthenium catalysts were conducted in different conditions in order to make the reaction more efficient and
achieve better materials. Results will be presented.
Reference
1] Butilkov, and N. G. Lemcoff, Green Chem., 2014, 16, 4728-4733.
2] Lavallo, Y. Canac, C. Prasang, B. Donnadieu, G. Bertrand, Angew. Chem. Int. Ed., 2005, 44, 5705 –
5709.
3] M. Marx, A. H. Sullivan, M. Melaimi, S. C. Virgil, B. K. Keitz, D. S. Weinberger, G. Bertrand, and
R. H. Grubbs, Angew. Chem. Int. Ed., 2015, 54, 1919 –1923.
4] Gawin, A. Kozakiewicz, P. A. Guńka, P. Dąbrowski, and K. Skowerski, Angew. Chem. Int. Ed.,
2016, DOI: 10.1002/anie.201609009.
29
PA-29
Sunscreen and Ruthenium Olefin Metathesis Catalysts: A One-Pot, Two-Step
Photochemical Synthesis of Coumarins
Or Eivgi, Gabriel N. Lemcoff
Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
We have recently demonstrated a novel type of chromatic selectivity by exploiting differences in molar
absorption coefficients. Thus, selective removal of photolabile protecting groups (PPGs) using internal or
external "sunscreens" was achieved using a single light source.1 Herein, the sunscreen methodology is applied
to the catalytic photo-induced cross metathesis (CM) reaction of 2-vinyl phenol derivatives protected with 2nitrobenzyl PPG. 2-vinyl phenols are impractical for olefin metathesis reactions due to stable chelate formation
with the ruthenium catalyst.2-4 By protection of the phenol moiety with a 2-nitrobenzyl PPG we can exploit the
large difference in the molar absorption coefficients at 380 nm UV light between the ruthenium catalysts
developed by our group5-7 and the 2-nitrobenzyl chromophore, to selectively activate the ruthenium catalyst
without removal of the 2-nitrobenzyl PPG in the presence of an external sunscreen solution. Thus, we can now
carry out a light triggered cross metathesis (CM) reaction of the acrylate esters and 2-nitrobenzyl protected 2vinyl phenols in 380 nm light, in the presence of an external solution of pyrene carboxaldehyde as a sunscreen.
While subsequent irradiation of the reaction vessel with 254 nm light after removal of the external sunscreen
prompts a chain of three reactions to yield the coumarin derivatives.
References:
(1)Eivgi, O. et al. Org. Lett. 2015, 17, 740
(2)Kozłowska, A. et al. Chem. Eur. J. 2014, 20, 14120
(3)Garber, S. B. et al. J. Am. Chem. Soc. 2000, 122,8168
(4)Kingsbury, J. S. et al. J. Am. Chem. Soc. 1999, 121, 791
(5)Ben-Asuly, A. et al. Organometallics 2009, 28, 4652
(6)Diesendruck, C. E. et al. Inorg. Chem. 2009, 48, 10819.
(7)Ginzburg, Y. et al. Organometallics 2011, 30, 3430.
30
PA-30
Cobalt Porphyrin-Graphene Systems for the Electrocatalytic Reduction of
Oxygen
Meital Eliyahu, Eli Korin, Armand Bettelheim
Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
Oxygen reduction reaction occurs on the cathode of fuel cells. This reaction is considered to be very sluggish
and therefore it is a necessity to use catalysts to improve the kinetics. Electrocatalytic reduction of oxygen
occurs in 2 main pathways: direct reduction of the oxygen to water by a four-electron pathway and indirect
reduction of oxygen by a two-electron pathway, forming hydrogen peroxide as an intermediate.
Although catalysts for oxygen reduction reaction that exhibit a very good activity exist, most of them are based
on noble metal catalysts, which are considered to be very expensive. Developing efficient non-noble metal
catalysts for the oxygen reduction reaction is one of the main keys to the production of commercially durable
fuel cell devices for future renewable energy applications. Porphyrins have been extensively studied and
demonstrated a good catalytic activity for oxygen reduction reaction, but most of them show activity only for
the two-electron pathway to yield H2O2. The present study deals with interactions, such as π-π stacking,
occurring between metalloporphyrin and graphene derivatives and their effect on the activity of the systems
towards O2 reduction.
Stable suspensions were obtained from 5,10,15,20-tetrakis(1-methyl-4-pyridinio) porphyrin (CoTMPyP) and
graphene oxide (GO) in a wide range of pH. UV/Vis spectroscopy measurements for suspensions of CoTMPyPGO at pH 7.2 showed a 9 nm red shift for the CoTMPyP Soret band observed around 433 nm, thus indicating ππ stacking. Cyclic voltammetry measurements for glassy carbon electrode coated with CoTMPyP-GO showed
that the O2 catalytic reduction peak is shifted 200 mV anodically in comparison to that observed for CoTMPyP
(-0.09 and -0.29 V vs. Ag/AgCl, respectively).
31
PA-31
Synthesis of Heavier Analogues Af alkenes, R2E=CR’2 (E= Si, Ge, Sn),
via Lithium Silanolate Elimination
Yuliya Goldshtein, Lieby Zborovsky, Victoria Molev, Dmitry Bravo-Zhivotovskii,
Yitzhak Apeloig
Schulich Faculty of Chemistry and the Lise Meitner-Minerva Center for Computational
Quantum Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
We report here the study of the reaction of tri-silyl-substituted lithium anions (R3Si)3ELi•nTHF 1, 3, 5, 6 (E =
Si, Ge, Sn) with 2-adamantanone, in order to prepare stable heavier analogues of alkenes (R 3Si)2E=CR’2 (E=
Si, Ge, Sn). We find that larger silyl-substituents on (R3Si)3ELi facilitate their reduction, but at the same time
provide stability to the desired product. In this work we aimed to find the best combination of silyl-substituents,
to obtain stable heavier analogues of alkenes.
The reaction of the most bulky silyl-branched (R3Si)3ELi 1 with 2-adamantanone leads to the corresponding Eradicals 2 i.e., only electron-transfer occurs. Decrease in the size of the silyl-substituents, e.g., 3a and 5a leads
to formation of a stable silene 4a. In contrast, the reaction of analogous stannyl lithium 3b leads to
corresponding radical. Reaction of silyl-branched stannyl lithium 5b with 2-adamantanone yields the stable
stannene 4c. Reaction of smallest silyl-branched (t-BuMe2Si)3E-Li 6 with 2-adamantanone leads to the
corresponding stable silene 7a and germene 7b, but to a transient stannene 7c, trapped by reaction with pquinone. The obtained products 2, 4, 7, 8 were characterized by NMR, EPR spectroscopy and some by X-ray
crystallography.
32
PA-32
Photochemical Reduction of CO2 with Visible Light using a Polyoxometalate
as Photoreductant
Eynat Haviv1, Ronny Neumann1, Linda J. W. Shimon2
Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
2
Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
1
The reduction of CO2 to a higher energy species such as CO is a key transformation and by and large an
important missing link towards the development of carbon-based solar fuels to remediate increasing amount of
CO2 in the atmosphere and replace finite amounts of fossil fuels. Both photochemical and electrochemical
pathways are being studied. The present state of the art teaches that the CO2 to CO reduction by

a photochemical pathway requires sacrificial tertiary amines as the source of electrons and
protons needed for the transformation and either low wavelength light or photosensitizers based on Ir
and Ru compounds.1

an electrochemical pathway that still requires prohibitively high potentials, typically higher than
1.7 V versus Ag/AgNO3.2
In order to overcome these two basic deficiencies, we combine a new di-rhenium molecular catalyst
active for CO2 photoreduction that also has a tether to bind a polyoxometalate via a simple acid-base
interaction. The polyoxometalate is an electron reservoir that can shuttle electrons from an electrode to
the molecular catalyst.
Now, in a cascade of transformations a new photoelectrochemical pathway is presented wherein a
polyoxometalate, the commercially available phosphotungstic acid, H3PW12O40, is electrochemically reduced at
low potential (1.3 V versus Ag/AgNO3), and low intensity visible light (60 W tungsten lamp) is used to
transfer electrons from the polyoxometalate to the catalyst that is active for selective reduction of CO2 to CO.
1] a)Ziessel, R., Hawecker, J., Lehn, J.-M., Chim. Acta, 69, 1990–2012 (1986). (b) Fujita, E., Coord.
Chem. Rev., 185-186, 373-384 (1999). (c) Takeda H., Koike K., Inoue H., Ishitani O., J. Am. Chem.
Soc., 130, 2023-2031 (2008).
2] Kumar, B., Llorente, M., Froehlich, J., Dang, T., Sathrum, A., Kubiak, C. P., Rev. Phys. Chem., 63,
541-569 (2102).
33
PA-33
Exploration of the Nature of the Anionic Ligands in Ruthenium Pre-Catalysts
Designed for Asymmetric Olefin Metathesis
Elisa Ivry, Gabriel N. Lemcoff
Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
Ruthenium alkylidenes complexes are key components in the promotion of the highly important metathesis
reaction. Throughout the years there have been extensive studies discussing the nature and impact of the
surrounding ligands within the catalytic sphere of these complexes. Replacement of the commonly used
chloride ligands in the known ruthenium alkylidenes by different halides and pseudo-halides showed that finetuning of the anionic ligands can lead to different reactivity and selectivity of the pre-catalysts.1 We have
recently demonstrated that asymmetric metathesis can be achieved by the facile installation of amino acids as
chiral anionic ligands.2 The use of readily available amino acids enables a simple protocol as well as easily
tuned properties. Nonetheless, due to the dynamic nature of the anionic position,3 reduction of the lability of the
carboxylate ligands was found to be crucial in improving the observed enantioselectivity. Therefore we are
currently focusing on probing the dynamic nature of the anionic position and its role in the stability and
reactivity of a variety of ruthenium complexes. Better understanding of the processes in which the anionic
ligands are involved, will lead to the synthesis of a stable, enantioselective ruthenium complex bearing amino
acid anionic ligands as chiral inducers.
References:
1 Anderson, E. B.; Buchmeiser, M. R. Synlett 2012, 2, 185.
2 Ivry, E.; Ben-Asuly, A.; Goldbergb, I.; Lemcoff, N. G. Chem. Commun. 2015, 51, 3870.
3 Tanaka, K.; Böhm, V. P. W.; Chadwick, D.; Roeper, M.; Braddock, D. C. Organometallics. 2006, 25, 5696.
34
PA-34
Towards Silanone via Bromosilanols and Bromosiloxanes
Alexander Kaushansky, Dmitry Bravo-Zhivotovskii, Yitzhak Apeloig
Schulich Faculty of Chemistry and the Lise Meitner-Minerva Center for Computational
Quantum Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
Stable isolable silanones, R2Si=O, the silicon analogue of ketones, are not yet known.
Here, we report the synthesis and X-Ray structural analysis of lithium bromosilanolate 3 and the reaction of
bromosiloxane 5 with silyllithium in hexane and in THF, which we believe yields a transient silanone.
Reaction of 2 with )Me3Si(2NLi yields trimer 3. X-Ray structural analysis of 3 reveals significant Li-Br
interactions, i.e. r(Li--Br) = 2.20 Å (shorter than the sum of their ionic radii), a very short r(Si-O) = 1.58 Å and
a relatively long r(Si-Br) = 2.29 Å.(see Figure 1) These structural features point to a major contribution of a
R2Si=O···LiBr complex character in 3. The structural features of 3 resemble those of dialkyl substituted dimeric
R2Si=O-LiBr complex recently published by Iwamoto.2 Hydrolysis of 3 yields diol 4. Disappointingly, heating
3 to 70°C in hexane or THF does not lead to LiBr elimination, indicating strong intermolecular bonding in 3.1
To prevent aggregation through strong O-Li-O interactions as in 3, the hydroxyl group in 2 was replaced by a
siloxy group, i.e., 5. Interestingly, reaction of 5 with tBu2MeSiLi is solvent dependent. In hexane this reaction
yields tris(silyl)silyllithium 7. However, in THF disilane 8 is produced together with what we believe is the
transient silanone 9. As expected, hydrolysis of 9 yields diol 4. We continue efforts to isolate silanone 9.
[1] A. Kaushansky, M.Sc. Thesis, Technion, Haifa, Israel, 2013.
[2] S. Ishida, T. Abe, F. Hirakawa, T. Kosai, K. Sato, M. Kira, T. Iwamoto, Chemistry – A European Journal
2015, 21, 15100-15103.
35
PA-35
Studying the Role of Anion Ligands in Organometallic Nanoparticles
Victoria Kobernik, Gabriel N. Lemcoff
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
In recent years the field of single chain organic nanoparticles has attracted the interest of the scientific
community due to their promising applications and ease of synthesis.1 By coordinating metals to a binding
polymer matrix under dilute conditions, intramolecular cross-linking could be achieved, leading to single chain
collapse and the formation of organometallic nanoparticles (ONPs).2
Polycyclooctadiene (PCOD) can coordinate rhodium chloride dimer complexes, leading to a change in the
polymer`s properties; e.g. its conductivity.2 The current study focuses on the possible role of the anion bridging
ligand in the ONPs with different anions made from PCOD and polybutadiene (PBD).3 This study may enable a
better understanding of the conductivity mechanism and will furnish a series of new ONPs with potential novel
properties.
References:
1.Mavila, S.; Eivgi, O.; Berkovich, I.; Lemcoff, N.G., Intramolecular Cross- Linking Methodologies for the
Synthesis of Polymer Nanoparticles, Chem. Rev., 2016, 116, 878–961.
2.a) Mavila S.; Diesendruck C.E.; Linde S.; Amir L.; Shikler R.; Lemcoff N.G., Polycyclooctadiene complexes
of rhodium (I): direct access to organometallic nanoparticles, Angew. Chem. Int. Ed., 2013, 52, 5767-5770. b)
Mavila S.; Rozenberg I.; Lemcoff N.G., A General Approach to Mono- and Bimetallic Organometallic
Nanoparticles, Chem. Sci., 2014, 5, 4196-4203.
3.Berkovich I.; Mavila S.; Iliashevsky O.; Kozuch S.; Lemcoff N.G., Single chain polybutadiene
organometallic nanoparticles: an experimental and theoretical study, Chem. Sci. 2016, 7, 1773-1778.
36
PA-36
Synthesis of Sila-Grignard Reagents Via Radical Activation of Si-H Bonds by
RMgX or R2Mg
Yosi Kratish, Yevgeni Mashin, Yuliya Goldshtein, Alexander Kaushansky,
Dmitry Bravo-Zhivotovskii, Yitzhak Apeloig
Schulich Faculty of Chemistry and the Lise Meitner Minerva Center for Computational
Quantum Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
Organomagnesium compounds play an important role in both organic and organometallic chemistry. In
contrast, the chemistry of silylmagnesium compounds is very limited, most probably due to the fact that
reactions of elemental magnesium with silyl halides do not lead to the formation of silylmagnesium compounds
but rather to Wurtz-type silicon-silicon coupling products. Reaction of silyllithium compounds with magnesium
halides is currently the most useful method for preparation of silylmagnesium compounds. However the limited
number of silyllithium reagents available is a major drawback.
Previously, we reported that organozinc reagents can activate Si-H bonds via a radical mechanism producing
silylzinc compounds [1]. Here, we report the first examples of radical activation of Si-H bonds in silyl
substituted hydridosilanes R(4-n)SiHn (n=1-3) by tBuMgCl and R`2Mg (R` = nBu, tBu, R``3Si) leading to a direct
sila-metalation reaction. Using this reaction we synthesized mono and bis magnesium substituted silanes from
the di-hydrido silane 1 (Eq. 1). Moreover, reaction of the tri-hydrido silane 2 with tBu2Mg yields the novel
trifunctional mono magnesium silane 3 which was then reacted with several electrophiles (Scheme 1). Addition
of tBu2Hg (radical initiator) increased the reaction yield significantly. Addition of 1,4-cyclohexadiene (radical
inhibitor) inhibited the reaction completely. These results support a radical mechanism similar to reactions of
silanes with organozinc reagents [1].
[1] R. Dobrovetsky, Y. Kratish, B. Tumanskii, M. Botoshansky, D. Bravo-Zhivotovskii, Y. Apeloig, Angew.
Chem. Int. Ed. 2012, 51, 4671.
37
PA-37
Self-Assembly of Peptide-Oligonucleotide Nanostructures
Agata Chotera, Gonen Ashkenasy
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
Systems chemistry attempts to mimic the complex biological networks within synthetic chemical framework.
Analysis of their dynamic self-organization, as well as self-replication and catalytic properties, can help us to
better understand the bottom-up organization of supramolecular architectures. Thus, we investigate selfassembly of synthetic peptide-oligonucleotide conjugates. Although peptide- and nucleic acids- based selforganizing systems are well documented in the literature, artificially synthesized hybrid molecules present a
unique family of compounds. Studying such conjugates will offer new superior soft matter suitable for many
applications and might even shed light on bottom-up scenarios related to the origin of life. Here, we present a
set of self-assembling peptide-DNA hybrids that have been designed and synthesized. Short nucleic acid
segments have been attached to amphiphilic replicating peptides previously explored in our lab 1-3. The basic
system consists of two conjugates, for which the oligonucleotide segment of one is complementary to the other
(Scheme 1). We demonstrate the self-assembly of our system into different morphologies: fibers and spherelike structures. To the best of our knowledge, this study proposes the first systematic analysis of structural and
functional characteristics of small peptide-DNA assemblies.
REFERENCES
1] B. Rubinov, N. Wagner, H. Rapaport and G. Ashkenasy, Angew Chem Int Ed Engl, 2009, 48, 66836686.
2] B. Rubinov, N. Wagner, M. Matmor, O. Regev, N. Ashkenasy and G. Ashkenasy, ACS nano, 2012,
6, 7893-7901.
3] M. Tena-Solsona, J. Nanda, S. Díaz-Oltra, A. Chotera, G. Ashkenasy, B. Escuder, Chem. Eur. J.,
2016 (DOI: 10.1002/chem.201600344).
38
PA-38
Total Chemical Synthesis of SUMO-2-Lys63-linked diUbiquitin Hybrid
Chains Assisted by Removable Solubilizing Tags
Emad Eid1, Somasekhar Bondalapati1, Patrick Lombardi2, Cynthia Wolberger2, Ashraf Brik1
1
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
2
Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of
Medicine, Baltimore, USA
Along with the known posttranslational modification by ubiquitin, known as ubiquitination, there are many
ubiquitin like modifiers such as the Small Ubiquitin Like Modifier (SUMO) proteins, which are know to
regulate many important cellular processes. Like ubiquitination, SUMOlytion is also mediated by E1, E2, and
E3 enzymes linked via an isopeptide bond to the C-terminal Gly of SUMO to a Lys residue from a target
protein. Recently, the hybrid chains of SUMO-ubiquitin and specifically SUMO-2 linked to Lys63-di-ubiquitin
were found to play major role in DNA repair. Despite some progress in understanding the role of the hybrid
chains in DNA repair, there are various fundamental questions remained to be answered. To farther investigate
the importance of hybrid SUMO-ubiquitin chains in DNA repair, homogenous material of the hybrid chains and
their unique analogs are needed in workable quantities. For the first time and by applying advanced chemical
strategies in protein synthesis we report the total chemical synthesis of four different SUMO-2-Lys63-linked diubiquitin hybrid chains. In this synthesis, the usefulness of removable solubilizing tags is demonstrated and
new lessons were learned for future studies where peptide fragments are difficult to handle and purify. The
availability of these chains open new opportunities in studying the role of these chains in DNA repair and other
cellular processes, which we are currently pursuing.
39
PA-39
Coiled Coil Protein Based Smart Surfaces Implementing Orthogonal Logic
Operations
Chiara Glionna1, Nurit Ashkenasy2, Gonen Ashkenasy1
Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
2
Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
1
Recently, the gap facilitating the utility of molecular logic systems for application in technological fields was
reduced after the implementation of molecular logics on solid surfaces, where molecules functionalizing the
surface are designed to respond to specific inputs. Coiled coil protein assemblies are suggested here as new
candidates for this task, due to their versatile properties and functionalities.[1] Here, we present reversible
surface attachment-detachment processes involving coiled coil proteins and describing orthogonal logic
operations. Coiled coil peptides have been designed, synthesized and characterized in solution by circular
dichroism and fluorescence spectroscopies. Several reversible binding and releasing, folding and unfolding
processes of heterodimeric coiled coil proteins have been performed on silicon nitride and gold surfaces. The
surface layer was characterized by ellipsometry, fluorescence and contact angle after each step. These
programmable reactions have been performed demonstrating Boolean logic operation. The coiled coil peptides
were labelled with a FRET couple, allowing the parallel implementation of two- and three-input logic gates,
NOR-OR and AND-ANH-NAND, following monolayer thickness, donor quenching, and wettability as readout.
The experiments accomplished demonstrated the feasibility of this system for reversible protein self-assembly
on solid surfaces. Surface properties can be dynamically dictated by functionalization with appropriate designed
proteins depending on the targeted device application. This new approach of programmable manipulation of
synthetic proteins on solid surface can pave the way to the development of more effective and flexible
biosensing devices.
[1] C. Shlizerman, A. Atanassov, I. Berkovich, G. Ashkenasy and N. Ashkenasy, J. Am. Chem. Soc., 2010, 132,
5070-5076.
40
PA-40
Dual Enzymatic Activation of Polymeric Micelles
Assaf J. Harnoy, Tamir Forsht, Sabina Panfilov, Einat Tirosh, Roey J. Amir
School of Chemistry, Tel Aviv University, Tel Aviv, Israel
Synthetic self-assembled nano structures and their interactions with enzymes have been drawing increased
attention as part of the growing interest in biocompatible and biodegradable stimuli-responsive polymeric
platforms. Utilization of enzymes as triggers that can modify the structural properties of polymeric assemblies
can be highly relevant for biological applications such as controlled drug delivery, tissue engineering, etc. The
key factors that grant enzymes the potential to act as stimuli are their catalytic efficiency, high selectivity
towards their substrates and vast natural abundance in biological tissues. Furthermore, many disease states are
frequently associated with a unique enzymatic over-expression, which could be exploited to stimulate cleverly
designed platforms in order to induce a site specific-response. Our research group recently developed a simple
synthetic approach for preparation of enzyme-responsive PEG-dendron hybrids. Our molecular design included
PEG as the hydrophilic backbone, while the enzyme-responsive functionalities were attached to the terminal
positions of a dendron unit. These amphiphilic hybrids were shown to self-assemble in aqueous media into
nano-sized polymeric micelles and to disassemble in response to the designed enzymatic stimulus. In this work,
we wished to expand the enzymatic trigger from a single enzyme into two activating enzymes by attaching two
different kinds of dendrons to the block copolymer junction. Each dendron unit was functionalized with
different substrates and activation by either one of the enzymes was shown to cause the micelles to disassemble
and release their encapsulated molecular cargo. In addition, simultaneous activation with both enzymes caused
the micelles to disassemble even faster, granting a much wider range of activation rates.
41
PA-41
Analyzing Amyloid Beta Aggregates with a Combinatorial Fluorescent
Molecular Sensor
Joydev Hatai, Leila Motiei, David Margulies
Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
The self-assembly of amyloid beta (Aβ) peptides into insoluble aggregates is thought to play a major role in the
progression of various neurodegenerative diseases, including Alzheimer`s disease (AD). Although various
studies have shown that subtle variations in the dynamics and compositions of Aβ aggregates could have a
significant impact on their physicochemical and pathological properties,1 currently there is no effective means
to straightforwardly characterize the Aβ aggregation state. Fluorescent assays, which mainly rely on the ‘turnon’ properties of a thioflavin T (ThT) molecule, can only detect the fibril formation, whereas other techniques
that can determine the content of these assemblies require special expertise and are not high-throughput. To
improve the ability to analyze Aβ aggregates, we have developed a combinatorial fluorescent molecular sensor
that generate a wide range of unique emission ‘fingerprints’ upon binding to distinct Aβ aggregate species. The
molecular sensor has been used to discriminate among aggregates generated from different alloforms (i.e., Aβ40
and Aβ42) or through distinct pathways, and it has also been used to track dynamic changes that occur in Aβ
aggregation states, which result from the formation of low molecular weight (LMW) oligomers, high molecular
weight (HMW), oligomers, protofibrils, and fibrils (Figure 1).
Figure 1. (a) Schematic representation of the Aβ aggregation process. (b) Chemical structure of a combinatorial
fluorescent molecular sensor 1. (c) Linear discriminating analysis (LDA) showed the ability of sensor to
discriminate among the various aggregates.
References.
1.Bitan, G.; Kirkitadze, M. D.; Lomakin, A.; Vollers, S. S.; Benedek, G. B.; Teplow, D. B., Proc. Natl. Acad.
Sci. 2003, 100, 330; (b) Benilova, I.; Karran, E.; De Strooper, B., Nat. Neurosci. 2012, 15, 349.
42
PA-42
Overcoming the Lack of Stereocomplementarity within Ene-reductases: The
Chemoenzymatic Synthesis of all four Stereoisomers of 2-Methylbutane-1,3diol
1
Marvin Rafael Mantel1, Elisabeth Rüthlein1, Thomas Classen2, Jörg Pietruszka1,2
Institute for Bioorganic Chemistry, Heinrich-Heine-University Düsseldorf at the Research
Center Jülich, Jülich, Germany
2
Institute of Bio - and Geosciences, Research Center Jülich, Jülich, Germany
The chemoenzymatic synthesis of small molecules can provide perfect stereoselectivity where organic methods
only supply a certain level of enantiopurity. However, enantiocomplementary enzymes are not always
accessible, preventing chemoenzymatic synthesis from becoming a versatile tool in accessing all stereoisomers
of a desired product. [1]
Herein we present an approach to overcome this problem by dexterous substrate-design instead of exhausting
catalyst-engineering. Two different substrates converted by the same ene-reductase enable access to
enantiocomplementary products. Next to the original substrate, ‘mirrored’ starting material can be converted in
a similar stereospecific fashion. Afterwards chemical modification of the residues following the enzymatic
reaction causes a priority-switch of the residues granting access to the missing isomers.
All remaining stereogenic information is installed by ADHs, matching the advantages of classic organic
methods and biocatalysis within a truly chemoenzymatic synthesis to all possible stereoisomers perfectly.
[1] (a) E. Rüthlein, T. Classen, L. Dobnikar, M. Schölzel, J. Pietruszka Adv. Synth. Catal. 2015, 375, 17751786 (b) Enzyme Catalysis in Organic Synthesis, Vol. 1, Wiley-VCH Verlag & Co. KGaA, Weinheim,
Germany, 2012.
43
PA-43
Identifying Small Protein Populations by a Combinatorial
Fluorescent Molecular Sensor
Zohar Pode1, Ronny Peri-Naor1, Joseph Georgeson2, Tal Ilani2, Vladimir Kiss3,
Tamar Unger4, Leila Motiei1, David Margulies1
1
Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
2
Structural Biology, Weizmann Institute of Science, Rehovot, Israel
3
Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
4
Israel Structural Proteomics Center, Weizmann Institute of Science, Rehovot, Israel
In recent years, a growing number of cross-reactive sensor arrays that can recognize proteins in a non-selective
manner have emerged. Although various differential sensors of this class have been developed and used to
discriminate among proteins, these systems are less suitable for analyzing specific populations of proteins in
their native environment. Cell-penetrating unimolecular sensors, on the other hand, are very specific and can
only detect one target at a time. In this study, we developed a unimolecular sensor that can detect different
proteins by generating unique identification patterns, similarly to cross-reactive arrays. We have shown that its
unimolecular scaffold and selective binding enable the combinatorial sensor to identify combinations of
proteins within complex biological mixtures and track several binding interactions simultaneously.
44
PA-44
Chemo-Enzymatic Labelling of the Epigenetic DNA Modification
5-Hydroxymethylcytosine
Gil Nifker, Micha Fridman, Yuval Ebenstein
Chemistry, Tel Aviv University, Tel Aviv, Israel
The field of Epigenetics focuses on DNA and chromatin modifications not encoded in the DNA sequence.
5-Methylcytosine (5-mC), DNA methylation, is known to play a key role in diseases and differentiation
mechanisms. It recently has been shown that 5-mC is oxidized to 5-hydroxymethylcytosine (5-hmC) in an
endogenous enzymatic reaction. 5-hmC, displays tissue specific distribution and has been related to gene
expression. For labeling purpose, 5-hmC can be selectively glycosylated by the β-glucosyltransferase enzyme
(β-GT), originated from the T4 bacteriophage; using a synthetic substrate that enables fluorescent tagging of
5-hmC residues via click chemistry. This approach has not been broadly adopted due to the challenging
synthesis and limited commercial availability of the glycosylation substrate 6-N3-UDPG. This work focused on
finding a solution for this problem.
45
PA-45
Strategy for the Development of Non-toxic Antimicrobial Cationic
Amphiphiles
Kfir B. Steinbuch
Department of Organic Chemistry, Tel Aviv University, Tel Aviv, Israel
Fungal infections are an increasing problem both in Western medicine and in regions with limited healthcare
availability. Mortality due to invasive fungal diseases likely exceeds that of tuberculosis or malaria with
Candida albicans and Candida glabrata as the most frequently treated opportunistic fungal pathogens. Inspired
by antimicrobial cationic peptides, we have developed several families of synthetic antimicrobial cationic
amphiphiles. We demonstrated that by manipulating structural motifs it is possible to enhance their selectivity
for microbial rather than mammalian red blood cell membranes. To date, none of the reported cationic
amphiphiles exhibited membrane selectivity sufficient to be considered for development of membranedisrupting antifungal agents.
Here in we report that the incorporation of cis-double bonds into the lipids of cationic amphiphile significantly
decrease their hemolysis and toxicity against mammalian cells. We demonstrated that increasing the degree of
cis-unsaturation in the lipid of antifungal cationic amphiphiles does not affect their antifungal activity against
Candida and decreases their hemolytic activity as well as their mammalian cell toxicity. One of the cationic
amphiphiles with a linolenic acid lipid residue, containing three cis-double bonds, displayed no cytotoxicity
against a panel of mammalian cell lines and primary cells. This compound selectively eradicated C. albicans
cells while not affecting the viability of human cells in co-culture experiments. Our findings offer a new
promising strategy for the development of non-toxic antimicrobial cationic amphiphiles safe for systemic
antifungal treatment.
46
PA-46
Characterizing Mineral-Bearing Vesicles in Sea Urchin Embryos
Keren Kahil1, Netta Vidavsky1, Eyal Shimoni2, Ifat Kaplan-Ashiri2, Lia Addadi1, Steve
Weiner1
1
Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
2
Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
Sea urchin embryos have endoskeletons comprised of two calcitic spicules. Spicule growth takes place by the
initial deposition of amorphous calcium carbonate (ACC)[1] in vesicles inside the spicule forming
cells[2](PMCs). The calcium in the mineral bearing vesicles was recently reported to originate from body fluid
internalization and in part from calcium channels[3]. Using cryo-scanning electron microscopy to image high
pressure frozen and cryo-sectioned samples of embryos, we were able to detect several types of vesicles inside
the PMCs. Some vesicles have granulated texture, some appear smooth, some have backscattered electrons
signal, and some contain lipids or proteins. Performing EDS measurements under cryogenic conditions revealed
that some of these vesicles are rich in sodium, while others give signals for potassium and calcium. We
conclude that the compositional landscape of the vesicles in the PMCs is complex. Some of these vesicles fulfil
a fundamental role in the mineralization of the spicules.
Figure 1 – Sea urchin embryo spicule (S) with its adjacent spicule forming cells. Red asterisks mark vesicles
with granulated texture suspected to be ACC.
[1] E. Beniash, J. Aizenberg, L. Addadi, S. Weiner, P Roy Soc B-Biol Sci 1997, 264, 461-465.
[2] N. Vidavsky, S. Addadi, J. Mahamid, E. Shimoni, D. Ben-Ezra, M. Shpigel, S. Weiner, L. Addadi, P Natl
Acad Sci USA 2014, 111, 39-44.
[3] N. Vidavsky, S. Addadi, A. Schertel, D. Ben-Ezra, M. Shpigel, L. Addadi, S. Weiner, Proc. Natl. Acad. Sci.
U.S.A 2016, 201612017, 201610027-201618424.
47
PA-47
One-Pot Conversion of Fluorophores to Phosphorophores
Sudhakar Kolanu, Matan Soll, Zeev Gross
Department of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
The porphyrinoids shows quite significant chemical and photophysical properties.1-3 Development of simple
and efficient procedures for corrole synthesis, combined with facile tuning of physical and chemical
characteristics by changing substituents on either the macrocycle or the chelate metal, has elevated in various
extensive applications.4,5
We have introduced a very efficient and facile one-pot conversion of free base 5,10,15tris(pentafluorophenyl)corrole, (H3)tpfc, into the coinage metal complexes of 2,3,17,18-tetraiodo-5-10-15tris(pentafluorophenyl)corrole, (I4-tpfc)M (M = Cu, Ag, Au). The iodoniation/metallation procedures provide
much higher yields and larger selectivity than both conceivable stepwise syntheses. Photophysical analysis
discloses that the gold(III) complex (I4-tpfc)Au displays phosphorescence at room temperature and a substantial
quantum yield for singlet oxygen formation. We trust the conclusions deduced from this research to be of large
utility for structure/activity tuning of other corroles and related ligands. We are presenting now our results on
the facile one-pot synthesis of group 11 metals with tetraiodinated-corroles, as well as some functionalization of
the C-I bonds therein.6
References:
1] Lemon, C. M.; Brothers, P. J. Porphyrins Phthalocyanines 2011, 15, 809.
2] Flamigni, L. The Chemical Rec. 2016, 47, 32.
3] Sudhakar, K; Giribabu, L; D’Souza, F. etc. –An Asian J. 2015, 10, 2708.
4] Vestfrid, J.; Goldberg, I.; Gross, Z. Chem. 2014, 53, 10536.
5] Vestfrid, J.; Kothari, R.; Kostenko, A.; Goldberg, I.; Tumanskii, B.; Gross, Z. Chem. 2016, 55, 6061.
6] Soll, M.; Sudhakar, K.; Fridman, N; Müller, A; Röder, B.; Gross, Z. Org. Lett. 2016 in press.
48
PA-48
The Redox Aqueous Chemistry of CuII/IATP
Ana Mesica1, Israel Zilbermann1,2, Magal Saphier2, Guy Yardeni2, Eric Maimon1,2,
Dan Meyerstein1,3
1
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
2
Department of Chemistry, Nuclear Research Center Negev, Beer-Sheva, Israel
3
Chemical Sciences Department and the Schlesinger Family Center for Compact Accelerators,
Radiation Sources and Applications, Ariel University, Ariel, Israel
Copper proteins have diverse roles in biological electron transport and oxygen transportation, processes that
exploit the easy interconversion of Cu(I) and Cu(II). As such, copper ions can act as both antioxidant and prooxidant species. Free radicals occur naturally in human body and can damage cell walls, interact with genetic
material, and contribute to the development of a number of health problems. Recent studies suggest that the
catalytic cycle of the Menkes’ protein begins with the binding of copper ions to high affinity binding sites in the
transmembrane channel, followed by ATP binding and transient phosphorylation.
Our study focuses on the interaction of ATP with both Cu(II) and Cu(I) ions and the redox activity of the latter
formed complexes in general, and their reactions with methyl radicals- the simplest example for .R formed in
biological tissues. The methyl radicals were produced in vitro by continuous radiolysis of N2O saturated
aqueous solutions containing DMSO.
While Cu(II)ATP was prepared by mixing the reagents at neutral pH (excess of ATP), the Cu(I) ATP was
prepared by comproportionation of Cu(II)ATP, ATP and Cu(0), as CV experiments showed thermodynamic
stabilization of the Cu(II)ATP/Cu(I)ATP with E1/2 ≈ +0.078V vs. Ag/AgCl and log K(Cu(I)ATP)≈11.
Cu(I)ATP reacted with .CH3 in a process in which the presumable metal carbon σ bond transient formed,
ATPCu(II)-CH3 decomposed heterolytically to give methane and Cu(II)ATP as the major products. Its divalent
analogue produced ATPCu(I)-CH3, which decomposed to give methane and ethane as minor products and
probably methanol(still to be proved) as the major product together with Cu(I)ATP.
Detailed data and mechanisms of reactions will be presented.
49
PA-49
Stability and Activity of Bimetallic Tips as Reduction Co-Catalysts
Eran Aronovitch1, Philip Kalisman2, Lothar Houben3, Lilac Amirav2, Maya Bar Sadan1
1
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
2
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
3
Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum
Jülich, Jülich, Germany
The search for alternative clean and renewable energy source is a major pressing issue. One promising direction
is the use of semiconductor nanoparticles as photocatalysts which absorb the solar radiation and produce
hydrogen from water. Upon radiation, excited electrons and holes are created. They then migrate to the surface
and react with the aqueous solution. Efficient photocatalysts should maintain charge separation of hole and
electron and contain different sites for oxidation and reduction. Usually a small metallic particle is deposited on
the semiconductor as a co-catalyst which acts as an electron sink and a reduction site for protons. Hybrid coreshell structures such as CdS@CdSe increase the charge separation and reduce the particle dissolution by
confining the holes to the core and leaving the electrons delocalized over the entire structure. A bi-metallic cocatalyst composed of metals such as gold and palladium should improve the photocatalytic activity of the
system. Such bimetallic particles possess the ability to attract electrons from the semiconductor and discharge
them into the aqueous solution more efficiently then each of the metals on their own. Here we use the
CdSe@CdS-Au\Pd system as a case study to explore the effect of the inner structure of the bimetallic tip on the
photocatalytic performance. In addition we study the dynamic processes which occur during photocatalysis
using both high resolution EDS imaging and online photocatalytic measurements.
50
PA-50
Surface and Depth Profiling of Soft Organic Thin Films.
X-Ray Photoelectron Spectroscopy Study
Tatyana Bendikov1, Simon Hutton2, Graham de Ruiter3, Renata Balgley3, Michal Lahav3,
Milko E. van der Boom3
1
Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
2
Research and Development Department, Kratos Analytical Ltd., Manchester, UK
3
Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
X-ray Photoelectron Spectroscopy (XPS) is uniquely suited for the direct characterization of nanomaterials and
thin films in terms of layer thicknesses, elemental composition and, frequently, the depth-distribution profile of
elements across the film. In general, XPS is limited to probe the top
Recent advances in depth profiling of organic and biological materials are based on sputtering with large Argon
ion clusters (Arn+).1 Unlike monoatomic ions (Ar+), large cluster ions do not penetrate deeply into the material,
therefore sputter material from the near-surface region only, leaving the subsurface layers undisturbed and
undestroyed.
Here we present two examples of successful XPS depth profiling of composite metal-organic architectures self
assembled on the pyridine terminated silicon/ ITO substrates. The samples consist of four main components:
metal complexes ([M(mbpy-py)3][PF6]2, M = Ru (1) or Os (2); Pd(PhCN)2Cl2 (3) and (1,4-bis[2-(4pyridyl)ethenyl]benzene, BPEB, (4) spacer molecules.
The first system was prepared by sequential immersion of the substrate in solution 1 (alternating with solution
3) (4 layers) followed by 2 (alternating with 3) (4 layers). Each layer is ~ 6 nm thick, thus the consequent total
thickness of the organic film reaches 40-50 nm.2
In the second example molecular assemblies consist of different layers of metal complexes 1 and 2, separated
by repetitive spacers 4 alternated with 3. Total thickness of the analyzed [Ru-BPEB12-Os] assembly is ~20 nm.3
1] J. Cumpson et. al., Surf. Interface Anal., 2013, 45, 1859-1868.
2] de Ruiter et. al., J. Am. Chem. Soc., 2013, 135, 16533-16544.
3] Balgley et. al., J. Am. Chem. Soc., 2016, in press.
51
PA-51
Photocatalytic Reactive Oxygen Species Formation by Semiconductor−Metal
Hybrid Nanoparticles. Toward Light-Induced Modulation of Biological
Processes
Yuval Ben-Shahar1, Nir Waiskopf1,2, Inbal Carmel1, Gilli Moshitzky2, Hermona Soreq2,
Uri Banin1
1
The Institute of Chemistry & The Center for Nanoscience and Nanotechnology,
The Hebrew University of Jerusalem, Jeerusalm, Israel
2
Department of Biological Chemistry and the Edmond and Lily Safra Center of Brain Science,
The Hebrew University of Jerusalem, Jerusalem, Israel
Semiconductor−metal hybrid nanoparticles manifest efficient light-induced spatial charge separation at the
semiconductor−metal interface, as demonstrated by their use for hydrogen generation via water splitting. Here,
we pioneer a study of their functionality as efficient photocatalysts for the formation of reactive oxygen species.
We observed enhanced photocatalytic activity forming hydrogen peroxide, superoxide, and hydroxyl radicals
upon light excitation, which was significantly larger than that of the semiconductor nanocrystals, attributed to
the charge separation and the catalytic function of the metal tip. We used this photocatalytic functionality for
modulating the enzymatic activity of horseradish peroxidase as a model system, demonstrating the potential use
of hybrid nanoparticles as active agents for controlling biological processes through illumination. The
capability to produce reactive oxygen species by illumination on-demand enhances the available peroxidasebased tools for research and opens the path for studying biological processes at high spatiotemporal resolution,
laying the foundation for developing novel therapeutic approaches.
52
PA-52
Crystallographic Mapping of Guided Nanowires by Second-Harmonic
Generation Polarimetry
Regev Ben-Zvi1, Lior Neeman2, Dan Oron2, Ernesto Joselevich1
Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
2
Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel
1
The growth of horizontal nanowires (NWs) guided by epitaxial and graphoepitaxial relations with the substrate
is becoming increasingly attractive owing to the posibility of controlling their position, direction and
crystallographic orientation1-3. In guided NWs, as opposed to the extensively characterized vertically grown
NWs, there is an increasing need for understanding the relation between structure and properties, specifically
the role of the epitaxial relation with the substrate. Furthermore, the uniformity of crystallographic orientation
along guided NWs and over the substrate has yet to be checked. Here we perform highly sensitive secondharmonic generation (SHG) polarimetry of polar and nonpolar guided ZnO. We optically map large areas on
the substrate in a nondestructive way, and find that the crystallographic orientations of the guided NWs are
highly selective and specific for each growth direction with respect to the substrate lattice. In addition, we
perform SHG polarimetry along individual NWs and find that the crystallographic orientation is preserved
along the NW in both polar and nonpolar NWs. However, while polar NWs show highly uniform SHG along
their axis, nonpolar NWs show a significant change in the local nonlinear susceptibility along a few microns,
reflected in a reduction of 40% in the ratio of the SHG along different crystal axes. We suggest that these
differences may be related to strain accumulation along the nonpolar wires. We find that SHG polarimetry to be
a powerful tool to study both selectivity and uniformity of crystallographic orientations of guided NWs with
different epitaxial relations4.
References
1. Tsivion, D.; Schvartzman, M.; Popovitz-Biro, R.; von Huth, P.; Joselevich, E., Science 2011,
333, 1003-1007.
2. Tsivion, D.; Schvartzman, M.; Popovitz-Biro, R.; Joselevich, E., ACS Nano 2012, 6, 64336445.
3. Oksenberg, E.; Popovitz-Biro, R.; Rechav, K.; Joselevich, E.,. Adv Mater 2015, 27, 3999- 4005.
4. Neeman, L.; Ben-Zvi, R.; Rechav, K.;, Popovitz-Biro, R.; Oron, D,; Joselevich, E., Nano Lett. 2016 “under
review”.
53
PA-53
Synthesis and Characterization of Smart Polymeric Nanoprobes for Real-Time
Optical Imaging
Racheli Blau1, Hemda Baabur-Cohen1, Shiran Ferber1, Yana Epshtein1, Orit Redy-Keisar2,
Einat Kisin-Finfer2, Doron Shabat2, Ronit Satchi-Fainaro1
1
Department of Physiology and Pharmacology, Tel Aviv University,
Sackler School of Medicine, Tel Aviv, Israel
2
School of Chemistry, Tel Aviv University,
Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv, Israel
Theranostics describes any material for applications combining both therapy and diagnostics (1). The great
challenge for future personalized therapy in oncology is exploring improved methodologies for (i) early
detection of localized and disseminated tumor cells in patients and (ii) monitoring drug release at the target site
in order to evaluate the treatment’s efficacy. The determination of both is critical to the success of cancer
therapy and improvement of patients’ survival rates. A theranostic nanosystem composed of a nanocarrier, a
drug and a Turn-ON probe is an ideal platform to address these challenges.
In this study, we designed, synthesized and characterized a theranostic nanomedicine based on N-(2hydroxypropyl) methacrylamide (HPMA) copolymer. The diagnostic system consists of self-quenched Cy5 and
the therapeutic system is based on the anticancer agent paclitaxel (PTX). Both systems were conjugated to
HPMA copolymer through a Gly-Phe-Leu-Gly (GFLG) linker, cleaved by cathepsin B, a lysosomal cysteine
protease, overexpressed in several tumor types. Our systems enable site-specific release of the drug
concomitantly with the fluorophore activation to its Turn-ON state upon enzymatic degradation (2). HPMA
copolymer-PTX conjugate inhibited the proliferation of endothelial and breast cancer cells.
Our preliminary results with the diagnostic nano-conjugate HPMA copolymer-Cy5 present its potential use as a
novel probe for sensing real-time drug release from the polymeric nanocarrier. This approach of co-delivery of
two complementary systems serves as a proof-of-concept for non-invasive real-time deep tissue intravital
orthotopic monitoring that may potentially be exploited as a theranostic nanomedicine in the clinic.
REFERENCES
1] S. S. Kelkar, T. M. Reineke, Bioconjugate chemistry 22, 1879 (Oct 19, 2011).
2] S. Ferber et al., Cancer letters, 352(1):81-9 (Mar 12, 2014).
54
PA-54
Preparation, Exfoliation and Investigation of MPS3 - Transition Metal
Phosphorous Trisulfides
Adam K. Budniak1, Tal Tabachnik2, Alex Dozortsev2, Yuval E. Yaish2, Michael Kalina3,
Alex Berner3, Marco Serra4, Rita Rosentsveig4, Reshef Tenne4, Efrat Lifshitz1
1
Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, Israel
2
Faculty of Electrical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
3
Department of Materials Science & Engineering, Technion-Israel Institute of Technology,
Haifa, Israel
4
Department of Materials and Interferences, Weizmann Institute of Science, Rehovot, Israel
Transition metal phosphorous trisulfides (MPTs) are layered compounds with chemical formula MPS3, where
M is divalent metal, P is Phosphorous and S is Sulphur. In the past bulk crystals of MPTs were widely studied
for application i.e. in lithium batteries [1]. Nowadays they are once again in scientific interest due to their
anisotropic properties and possibility to obtain and study their monolayers [2].
MPTs are two dimensional (2D) semiconductors, also called layered semiconductors, as they are built from
stacks of single molecular sheets. They have strong, covalent bonds within layer and between them there are
only weak van der Waals interactions. The intra-layer interactions are 1-2 orders of magnitude stronger than
inter-layer ones and this anisotropy of structure has great impact on their properties. For example, it is relatively
simple to receive few or even monolayer forms or to intercalate these compounds. Moreover, such a decreasing
of size in one dimensions leads to observing special phenomena in case of electrical or magnetic properties.
The poster will present synthesis and characterization of bulk, few and monolayers of MPTs, i.e. FePS3. NiPS3.
Bulk crystals were obtained by vapor transport furnace synthesis and exfoliation was performed by two
approaches: mechanical and chemical. Received products were characterized for example by SEM coupled with
EDS, Raman spectroscopy (temperature depended measurements) and Atomic Force Microscopy (AFM).
Acknowledgments:
This work was supported by the European Comission via the Marie-Sklodowska Curie action Phonsi (H2020MSCA-ITN-642656)
References:
[1] R. Brec, Solid State Ionics, 1986, vol. 22, no. 1, 1986.
[2] K.-z. Du et. al., ACS Nano, vol. 10, no. 2, 2016.
55
PA-55
Carbon Nanotube Based Flow-Through Electrochemical Cell for
Electroanalysis
Andrea Buffa1, Yigal Erel2, Daniel Mandler1
Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
2
Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
1
A novel approach is proposed for increasing the sensitivity and reducing the time required for the
electrochemical detection of both organic and inorganic pollutants in water. In the present work a membrane
flow-through electrode made of multi walled carbon nanotubes (MWCNT) buckypaper is utilized for the
detection of copper by anodic stripping voltammetry and parathion and tartrazine by adsorptive stripping
voltammetry. The convective mass transfer obtained in flow condition combined with the large surface area and
adsorptive properties of buckypaper enables an efficient accumulation of the analyte on the electrode surface in
a short time, improving sensitivity and time efficiency. Buckypaper porous electrodes were prepared by
filtration of MWCNT dispersion through a PTFE membrane and their sheet resistance and water permeation
flux resulted to be inversely proportional to the thickness of the MWCNT layer. We demonstrated that for
analytical applications thin membranes electrodes perform better than thick electrodes in virtue of their higher
permeability and lower capacitance. In particular, buckypaper membranes with a surface mass of 0.12 mg cm −2
enabled the detection of 64 ppt of copper in 5 min, 53 ppb of tartrazine in 2 min, and 0.12 ppm of parathion in 1
min. Thus, the electrochemical sensor based on the MWCNT porous flow-through electrode promises to be a
key part of the quality control of drinking water at any level of the water supply chain. Moreover, the water
permeation flux of 10200 L h−1 m−2 achievable with buckypaper membrane electrode associated with an
electrical conductivity of 2200 S m−1 makes this system also suitable for large scale electrochemical water
treatment.
56
PA-56
Matrix Metalloproteinase Coated- and Ag-Encapsulated Polydopamine
Nanoparticles with Antibacterial and Wound Healing Activities
Shira Carmi, Pini Hasin, Shai Rahimipour
Chemistry, Bar-Ilan University, Ramat-Gan, Israel
The effect of bacterial infection on wound healing process is a factor that can delay healing. Chronic wounds,
such as those occur on diabetic patients are often colonized by bacteria, which can lead to deadly systemic
infections. We have recently reported that Ag-encapsulated polydopamine nanoparticles (Ag-PDA-NPs) exhibit
potent antibacterial and antibiofilm activities against a variety of bacteria, including gram-positive S. aureus
and S. mutans, and gram-negative E. coli and P. aeruginosa (1, 2). In this study, we report on the antibacterial
and wound healing activities of Ag-PDA-NPs, whose surface is decorated with the enzyme membrane-type 1
matrix metalloproteinase (MT1-MMP). MT1-MMP is involved in cell migration process, where it degrades
extracellular matrix to enable cell migration. The PDA-NPs were characterized by electron microscopy (SEM
and TEM) and X-ray photoelectron spectroscopy (XPS), which confirmed the presence of Ag0 in the core of the
particles, whereas the presence of MT1-MMP on the shell of the PDA-NPs was confirmed by zeta potential
analysis, and immunochemically using an anti-MT1-MMP antibody. The hybrid PDA-NPs demonstrated low
cell toxicity, while exhibited potent antibacterial activity. The particles also stimulated the migration of NIH3T3 fibroblast cells, suggesting that MT1-MMP-modified Ag-PDA-NPs could be used as multi-functional
topical intervention for infected chronic wounds.
1] Yeroslavsky, M. Richman, L. Dawidowicz and S. Rahimipour, Sonochemically produced
polydopamine nanocapsules with selective antimicrobial activity. Chem. Commun., 2013, 49, 57215723.
2] Yeroslavsky, R. Lavi, A. Alishaev and S. Rahimipour, Sonochemically-Produced Metal-Containing
Polydopamine Nanoparticles and Their Antibacterial and Antibiofilm Activity. Langmuir, 2016, 20,
5201–5212.
57
PA-57
Highly Thermostable and Insensitive Energetic Hybrid Coordination
Polymers Based on Graphene Oxide–Cu(II) Complex
Adva Ziv Cohen1, Yuzhang Yang2, Qi Long Yan1, Avital Shlomovich1, Natan Petrutik1,
Larisa Burstein1, Si-Ping Pang2, Michael Gozin1
1
School of Chemistry, Faculty of Exact Science, Tel Aviv University, Tel Aviv, Israel
2
School of Material Science & Engineering, Beijing Institute of Technology, Beijing, China
New highly energetic coordination polymers (ECPs), based on the graphene oxide (GO)-copper(II) complex,
have been synthesized using 5,5′-azo-1,2,3,4-tetrazole (TEZ) and 4,4′-azo-1,2,4-triazole (ATRZ), as linking
ligands between GO-Cu layers. The molecular structures, sensitivity, and detonation performances of these
ECPs were determined. It was shown that these energetic nanomaterials are insensitive and highly
thermostable, due to high heat and impact dissipation capacity of GO sheets. In particular, the GO-TEZ-Cu(II)
ECP shows low sensitivity to impact and electrostatic discharge (Im = 21 J; ESD of 1995 mJ) and has a
comparable detonation performance to RDX. Also, our novel GO/Cu(II)/ATRZ hybrid ECP GO-Cu(II)-ATRZ
ECP exhibits high density (2.85 g·cm–3), remarkably high thermostability (Tp = 456 °C), and low sensitivity (Im
98 J; ESD of 1000 mJ). The latter material has a calculated detonation velocity of 7082 m·s–1, which is slightly
higher than that of energetic ATRZ-Cu(II) 3D MOF and higher than one of the top thermostable explosives
HNS (Tp = 316 °C; 7000 m s–1).
58
PA-58
Colloidal Cu2O Nano-Crystal Photoelectrodes: The Role of Interfacial
Chemistry
1
Yaron Cohen1,2, Kathy Vinokurov2, Matan Leiter2, Uri Banin2
Department of Chemistry, Nuclear Research Centre Negev, Beer-Sheva, Israel
2
Institute of Chemistry and the Center for Nanoscience and Nanotechnology,
The Hebrew University of Jerusalem, Jerusalem, Israel
Organic ligands are integral constituents of colloidal nanocrystals (NCs) and play an important role in their
synthesis, their compatibility with different solvents and the electronic properties. We have studied the role of
the interfacial chemistry in the charge transfer and passivation against photocorrosion of
octadecylamine(ODA)-coated cuprite (Cu2O) NCs for solar water splitting applications. ODA ligands are very
efficient surfactants for the synthesis of nanoscale octahedral Cu2O NCs with narrow size distribution. In
addition, the long alkyl-chain ODA molecules form a highly hydrophobic monolayer on top of the NCs that
reduces the contact with the aqueous solution and may improve the passivation of the NCs towards
photocorrosion, which is a major challenge of Cu2O for solar water splitting applications. Photoelectrochemical
measurements of Cu2O NCs thin layers on Au electrodes show, though, that the ODA molecules that cover the
NCs impede the transport of the photogenerated charges to the liquid and, thus, suppress the photoresponse
under solar illumination. Ligand exchange procedure is, then, carried out with more conductive molecules in
order to improve the photo-induced charge separation and transport across the Au-NCs-liquid interfaces and to
increase the photoresponse of the NCs.
59
PA-59
Tailoring the Electronic Structure of Y-doped NbBiO4 using Oxygen-vacancy
for All-oxide PV Applications: A Theoretical and Experimental Study
Susanta Das, Vijay Singh, David Keller, Dan Thomas Major
Department of Chemistry, Bar-Ilan University, Ramat-Gan, Israel
Recently, combined Density Functional Theory (DFT) and experimental studies revealed that Bi 2O3 is a low
band-gap material and the obtained energy band-gap, 2.30 eV, lies in the region of PV interest.1 The observed
optical transitions between the valence band (VB) (O-2p states) and the conduction band (CB) (Bi-6p states) are
not allowed due to violation of the dipole selection rule (Δl =+/-1). Therefore, Bi2O3 is not a potential absorber
material for PV application.2 With the aid of DFT calculations and experimental measurements, we have further
studied the hybrid NbBiO4 system and our calculations revealed that its valence and conduction bands consist
of optically active states, but its large energy band gap, 3.50 eV, puts a constraint on its use as an absorber
material. In the present work, with the help of suitable doping as well as oxygen vacancy, we were able to
reduce the energy band gap of NbBiO4, from 3.50 eV to 2.20 eV without changing its electronic structure.
In the framework of DFT, we revealed that doping of Yttrium (Y) has a remarkable effect on NbBiO 4 for PV
applications.3 Moreover, we find that Y doping at Bi-sites i.e. Y@Bi sites in NbBiO4 with the presence of +2
oxygen charge defects change the electronic structure and reduces the band gap to 2.20 eV. 4 The observed band
gap is in the PV region and the transition between the CB and VB states are optically allowed. Thus, the
combination of doping and defect has a dramatic effect on NbBiO4 PV activity.
References:
[1] Chris E. Mohn, Svein Stølen, Stefan T. Norberg, and Stephen Hull. Phys. Rev. B, 2009, 80, 024205 024212
[2] Christoph Freysoldt, Blazej Grabowski, Tilmann Hickel, Jörg Neugebauer, Georg Kresse, Anderson Janotti,
Chris G. Van de Walle. Rev. Mod. Phys. 2014, 86, 253 – 305.
[3] Nirmal Ganguli, Indra Dasgupta and Biplab Sanyal. J. Appl. Phys. 2010, 108, 123911 – 123918.
[4] Nimrod Yavo, Alaric D. Smith, Ori Yeheskel, Sidney R. Cohen, Roman Korobko,Ellen Wachtel, Peter R.
Slater, and Igor Lubomirsky. Adv. Funct. Mater. 2016. 26, 1138–1142
60
PA-60
Design Synthesis for Magnetic Impurity Positioning within CdSe/CdS
Core/Shell Colloidal Quantum Dots
Joanna Dehnel
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
Recently, research interest has shifted toward colloidal quantum dots (CQDS) embedded with magnetic
impurities, such as a Mn2+ ion [1]. The incorporation of magnetic ions initiates spin exchange interaction
between the guest ions’ spins and host carriers’ spins, the so called sp-d exchange interaction, which induces
mutual spin alignment followed by creation of giant magnetization and a long spin-coherent time [2]. Hence,
present of magnetic impurities strongly influence the optical, electronic and magnetic properties of the
semiconductors.
Here, we will present a design of colloidal synthesis procedure for incorporation of Mn 2+ ions into CdSe/CdS
core/shell CQDs by controlled layer-by-layer growth methods. Such a procedure allows us to positioning of the
Mn 2+ ions at a desired radial distance from the nanocrystal (NC) centre, either within the core or within the
shell. Special platform of NCs will permit selective interaction of the resident host carriers with the guest ion`s
spins. We show evidence of successful in embedded Mn2+ ions at low dilution in CdSe/CdS CQDs and the
electron spin resonance (ESR) studies reveal the Mn2+ ions local environments within the QDs
[1] Beaulac, R.; Archer, P. I.; Ochsenbein, S. T.; Gamelin, D. R. Mn2+-Doped CdSe Quantum Dots: New
Inorganic Materials for Spin-Electronics and Spin-Photonics. Advanced Functional Materials, 2008, 18 (24),
3873-3891.
[2] Govorov, A.O.; Kalameitsev, A.V. Optical properties of a semiconductor quantum dot with a single
magnetic impurity: photoinduced spin orientation. Phys. Rev. B. 2005, 71(3), 35338.
61
PA-61
Designing Plasmon-Molecule Interactions
Lihi Efremushkin1, Adi Salomon1, Maxim Sukharev2
1
Department of Chemistry, Institute of Nanotechnology, Bar-Ilan University, Ramat-Gan,
Israel
2
Science and Mathematics Faculty, College of Letters and Sciences, Arizona State University,
Arizona, USA
In this work we show theoretically and experimentally that a molecular system at very low concentration can be
strongly coupled to plasmonic modes. Upon coupling new hybrid states are formed, lower and higher
polaritons. These modes have the characteristics of both molecular and plasmonic states and also new
characteristic different from those of the molecular and plasmonic states. As the coupling strength grows
increasing of molecular concentration asymmetric splitting is observed giving rise to enhanced transmission
through metallic hole arrays. Moreover, we have also succeeded in reaching a linear dependency of the Rabi
splitting value on the square root of the absorbance which is another proof for strong coupling.
We also show that by tuning the plasmonic modes we are able to be on/off resonance with respect to the
molecular system and therefore generate new photonic-exciton hybrid states at different energies and as a
consequence with unique properties. Moreover, we show that by changing the distance between the plasmons
and the molecules we can design the strong interactions between the two systems.
(a) Schematic illustration of the system used. The system is composed from fabricated Ag film placed between
glass and PVA or porphyrin derivative embedded in PVA. (b) Absorbance spectrum of porphyrin derivative
embedded in PVA spin coated onto glass. The absorbance is ca. 0.016. The inset is a SEM image of the
fabricated Ag film.
62
PA-62
Heterogeneous Ice Nucleation on Polar Crystals: the Role of Water Clusters
and Surface Charge
David Ehre, Alik Belitzky, Sofia Curland, Meir Lahav, Igor Lubomirsky
Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
The ability to control the freezing temperature of super-cooled water (SCW) with auxiliaries is of vital
importance in the living and unanimated worlds and currently identified as one of the top open questions in the
ice sciences.
In the 90’s Prof. Meir Lahav, who is a member of our group, together with Prof. Leslie Leiserowitz were
investigate super-cooled water freezing on organic monolayers and crystals. One of their finding was that
alpha-amino acid crystals that have a polar axis induce a freezing point higher by 4° to 5°C than the
corresponding crystals that do not have a polar axis 1. In 2010 we published that that in pyroelectric LiTaO3
crystal SCW freezes on a positively charged surface at a much higher temperature than on a negatively charged
one 2. In a recent publication, we show that the source of pyroelectric enhance SCW freezing is the surface
charge and not the electric field 3. New results suggest that this charge effect occurs only on hydrophilic
surfaces. In the case of hydrophobic surface, the initial water organization due to the crystal polarity is probably
the dominate factor.
Reference:
1
J. Majewski, R. PopovitzBiro, R. Edgar, M. ArbelHaddad, K. Kjaer, W. Bouwman, J. AlsNielsen, M. Lahav,
and L. Leiserowitz, J Phys Chem B 101, 8874 (1997).
2
D. Ehre, E. Lavert, M. Lahav, and I. Lubomirsky, Science 327, 672 (2010).
3
A. Belitzky, E. Mishuk, D. Ehre, M. Lahav, and I. Lubomirsky, J. Phys. Chem. Lett. 7, 43 (2016).
63
PA-63
Spherical Inorganic Superfullerenes: Rationalization of Unique Gated
Confinement at the Nanoscale
Somenath Garai1,2, Alice Merca1, Mirta Rubčić1, Hartmut Bögge1, Achim Müller1
1
Fakultät für Chemie, Universität Bielefeld, Bielefeld, Germany
2
Currently at Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
The unique spherical nanocapsules/Keplerates of the type {{(Mo)Mo5}12M’30} (M’ = {MoV2}, VIV, CrIII, FeIII)
(more generally: (pentagon)12(spacer/ligand)30) allow – due to their exceptional structural features and easy
variations/derivatizations – versatile chemistry and applications as well as the option to study new phenomena
of interdisciplinary interest.[1] In this poster we specially refer on the interesting neutral/charged species of
[{(MoVI)MoVI5O21(L)6}12{FeIII(H2O)L}30] (L = H2O/CH3COO-/Mo2O8/9n-) 1a/type[2] not only because of their
tremendous unusual magnetic properties which exhibit spherical networks based on corner-shared M’3 triangles
causing geometrical frustration analogous to that of the planar Kagomé lattices but also for their behavior as
unique weak polyprotic acids owing to the external water ligands attached to the M’ metal centers. In the
second part we refer to the fact that the capsule [{(MoVI)MoVI5O21(H2O)6}12{MoV2O4(CO3)}30]72- 2a[3]
containing 30 carbonate ligands is a potential starting reagent for the synthesis of novel capsules with weakly
coordination ligands such as fluoride ions [{(MoVI)MoVI5O21(H2O)5F}12 {MoV2O4(F)(H2O)}30]69- 3a.[4]
Fig. Ball-and-stick representation for the structures of 1a, 2a and 3a
[1] A. Müller, P. Grouzerh, Chem. Soc. Rev., 2012, 41, 7431.
[2] A. Müller, S. Sarkar, S. Q. N. Shah, H. Bögge, M. Schmidtmann, S. Sarkar, P. Kögerler, B. Hauptfleisch, A.
X. Trautwein, V. Schünemann, Angew. Chem. Int. Ed., 1999, 38, 3238.
[3] S. Garai, E. T. K. Haupt, H. Bögge, A. Merca, A.Müller, Angew. Chem. Int. Ed., 2012, 51, 10528.
[4] S. Garai, M. Rubčić, H. Bögge, E. T. K. Haupt, P. Gouzerh, A.Müller, Angew. Chem. Int. Ed., 2015, 54,
5879 (VIP paper).
64
PA-64
Electropolymerization as a New Route to g-C3N4 Coatings on TiO2 Nanotubes
for Photoelctrochemical Degradation of Organics in Water
Shuli Halevy, Armand Bettelheim, Eli Korin
Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
Waste treatment becomes a major problem in the world and various technologies have been suggested for this
purpose. Photoelectrochemical (PEC) oxidation is one of the promising technologies for the treatment of
organic pollutants in water since it enables oxidation of organic compounds to CO2. The common concept of
photoanodes preparation is to use planar and transparent electrodes coated with nanostructured photocatalysts.
However, the employed coating methods not always provide high efficient surface area. This limits large scale
applications in PEC cells.
In the present work porous photoanodes based on TiO2 nanotube (NT) arrays were prepared via anodization of
Ti foils followed by annealing at 500 ̊C. These are characterized by good exposure to light and high surface
area for photocatalytic reaction. SEM images revealed TiO2NTs with a length of 3-10 µm and an average tube
diameter in the range of 50-150 nm. XRD showed that anatase TiO2 was formed after annealing the anodized Ti
foil.
Continuous coatings of g-C3N4 were obtained on TiO2NTs by a new and simple process consisting of melamine
electropolymerization followed by a heat treatment. According to TEM observations, coatings with a thickness
of 2-3 nm were uniformly distributed on the surface of the TiO2NTs. The chemical nature of the films was
identified by X-ray diffraction and a variety of spectroscopic methods. The performances of the Ti/TiO2 and
TiO2/g-C3N4 photoanodes were examined in a PEC cell for methanol degradation. The methanol photooxidation
onset potential in a solution of 1 M methanol shifted cathodically by 100 mV for TiO2/g-C3N4 as compared to
Ti/TiO2. Moreover, an increase of 60% of the methanol (1 M) limiting photocurrent density was observed for
TiO2/g-C3N4.
65
PA-65
Cation Exchange Combined with Kirkendall Effect in the Preparation of
SnTe/CdTe and CdTe/SnTe Core/Shell Nanocrystals
Youngjin Jang1, Diana Yanover1, Richard Karel Čapek1, Arthur Shapiro1, Nathan Grumbach1,
Yaron Kauffmann2, Aldona Sashchiuk1, Efrat Lifshitz1
1
Schulich Faculty of Chemistry, Russell Berrie Nanotechnology Institute, Solid State Institute,
Technion - Israel Institute of Technology, Haifa, Israel
2
Department of Materials Science and Engineering, Technion - Israel Institute of Technology,
Haifa, Israel
Controlling the synthesis of narrow band gap semiconductor nanocrystals (NCs) with a high-quality surface is
of prime importance for scientific and technological interests. This abstract presents facile solution phase
syntheses of SnTe NCs and their corresponding core/shell heterostructures. Here, we synthesized monodisperse
and highly crystalline SnTe NCs by employing an inexpensive, nontoxic precursor, SnCl2, the reactivity of
which was enhanced by adding a reducing agent, 1,2-hexadecanediol. Moreover, we developed a synthesis
procedure for the formation of SnTe-based core/shell NCs by combining the cation exchange and the
Kirkendall effect. The cation exchange of Sn2+ by Cd2+ at the surface allowed primarily the formation of
SnTe/CdTe core/shell NCs. Further continuation of the reaction promoted an intensive diffusion of the Cd 2+
ions, which via the Kirkendall effect led to the formation of the inverted CdTe/SnTe core/shell NCs.
66
PA-66
Trimeric Surfactant as Boundary Lubricant
Nir Kampf1, Chunxian Wu2, Yilin Wang2, Jacob Klein1
1
Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
2
Key Laboratory of Colloid and Interface Science, Institute of Chemistry,
Chinese Academy of Sciences, Beijing, China
Surfactants are widely used to modify surfaces and interfaces properties. Unique cationic trimeric surfactant
was found to form liposome-like aggregates in solution (1, 2). The surface structure of the trimeric surfactant
tri(dodecyldimethylammonioacetoxy)-diethyltriamine trichloride (DTAD) on mica, and the interactions
between two such DTAD-coated surfaces were determined using atomic force microscopy and a surface force
balance. In an aqueous solution of 3 mM, five times the critical aggregation concentration (CAC), the surfaces
are coated with worm-like micelles or hemi-micelles and larger (ca. 80 nm) bilayer vesicles (3). This surface
coating is strongly lubricating up to some tens of atmospheres, attributed to the hydration-lubrication
mechanism acting at the exposed, highly hydrated surfactant headgroups. Moreover, on replacing the DTAD
solution by surfactant-free water, the surface structures have changed to a smooth and hydrophobic monolayer.
Surprisingly, this trimeric surfactant monolayer, which is highly hydrophobic, is at the same time positively
charged under water. These monolayers are stable over days even under salt solution (3). The stability is
attributed to the several stabilization pathways available to DTAD on the mica surface.
References
(1) Hou et al., Langmuir, 24, 10572 (2008).
(2) Wu et al., Langmuir, 26, 7922 (2010).
(3) Kampf et al., Langmuir, 26, 7922 (2016).
67
PA-67
Detecting Molecules of Biological Interest via Solid State Nanopores
Abeer Karmi, Dvir Rotem, Michelle Akerman, Danny Porath
Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
Nanopores have become known recently for their sensing abilities. They have the potential for uses in medical
diagnosis and personalized medicine.
Solid state nanopores are fabricated by drilling through a thin insulating membrane composed of Si3N4 using
HR-TEM. The membrane is then placed between two chambers filled with electrolyte solution and ionic current
flowing through the pore is electrically monitored. The desired analyte can be driven through the pore by
voltage application. When an analyte is translocated through the pore, a blockage in the ionic current, which is
typical to the analyte, is observed.
We focus on developing the performance of solid-state nanopores in detecting the desired analyte (DNA, GNPs
and proteins). One major goal is hybridizing the pore with SP1 protein pore, the hybrid pore will combine the
advantages of the protein pore and the solid state nanopore, and will present better interaction between the pore
and DNA, hence, slowing down the speed of translocation.
68
PA-68
Development of Novel Carbon Dots based Materials for Physical and
Biological Worlds
Vijay Bhooshan Kumar1, Aharon Gedanken1, Zeev Porat3, Doron Aurbach1, Vilas Pol5, Orit
Safi4, Yaron Shavtal2, Ehud Banin2
1
Department of Chemistry, Bar-Ilan University, Ramat-Gan, Israel
2
Department of Life Science, Bar-Ilan University, Ramat-Gan, Israel
3
Department of Chemistry, Nuclear Research Center Negev, Beer-Sheva, Israel
4
School of Engineering, Bar-Ilan University, Ramat-Gan, Israel
5
Chemical Engineering Department, Purdue University, West Lafayette, Indiana, USA
One-step sonochemical synthesis of carbon dots (C-dots), which is carried out by sonication of pristine
polyethylene glycol (PEG-400) for 0.5-3 hour. It demonstrates how various experimental parameters, such as
the sonication time, the temperature and the amplitude of sonication affect the size of the C-dots (2-10 nm) and
their fluorescence. The highest measured quantum yield of emission was ~16-44%. Similarly, we synthesized
C-dots doped with metals (Ga, In, Sn) and non-metals (N, P, S) for various applications, such as supercapacitor,
Lithium ion rechargeable battery, biodiesel production, bio-imaging, antibacterial activity, Neural cell growth,
and gene delivery. The synthesized C-dots were coated on polythene, Si-wafer and activated carbon (AC). Cdots were used for bio-imaging, whereas AC/C-dots were used as supercapacitors. Electrodes made of AC/Cdots demonstrated specific capacitance of 0.185 F.g-1.cm-2, almost 3 times higher than unmodified carbon. The
Sn@C-dots@Sn nanoparticles were synthesized and directly deposited on the copper foil current collector as a
promising anode for Li-ion batteries. The letter, C-dots modified SrO NPs was prepared from the Sr-based salt
(Sr(NO3)2) and to study their physical, chemical and catalytic behavior. This catalyst (SrO-C dot composite) is
very useful as a catalyst for biodiesel production from the cooked waste oil and Chlorella vulgaris microalgae.
Similarly, TiO2 materials was synthesized and used for photocatalytic activity. The Ga doped in C-dots
(Ga@C-dots) and used for antimicrobial activity against free-living P. aeruginosa bacteria. Ga@C-dots was
reflected full inhibition of the bacterial growth at the much lower concentration of Ga within Ga@C-dots. We
also observed that cells grown on a Ga@C-dots@Ga-coated substrate exhibit a 96% increase in the number of
branches originating from the soma (SH-SY5Y cells).
69
PA-69
Synthesis of High-Performance Ru-doped MoSe2 Heirarchical Nanoflowers for
Hydrogen Evolution Reaction
Vasu Kuraganti, Maya Bar Sadan
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
Hydrogen production using a stable, cost-effective and earth abundant catalyst via electrochemical and
photochemical water-splitting has received enormous research interest in recent years. Two dimensional
layered materials, such MoS2, WS2 and MoSe2, are efficient catalyst electrode material for electrochemical
hydrogen evolution reaction (HER). It has been reported that the catalytic activity of these materials originates
from the active edge sites, while Basel plane electrically and chemically remains inert. Therefore, syntheses of
MoS2 and MoSe2 novel nanostructures have effective active edge sites with enhanced HER activity are greatly
appreciate. In the present study, Ru doped MoSe2 3D heirarchical nanoflowers were synthesized using colloidal
method and the HER activity of the catalyst was investigated as a function Ru atomic percentage. Flower-like
structure was stabilized in Mo1-xRuxSe2 samples for different x values (x= 0, 0.075, 0.11, 0.18 and 0.3) and the
sizes were spanning in the range 500-200 nm respectively. X-ray diffraction (XRD) pattern revealed that the
Ru-doped MoSe2 nanoflowers were crystallized into 2H-hexagonal crystal structure. Optical excitons A and B
show red shift in absorption spectra with increasing Ru atomic percentage. Mo1-xRuxSe2 samples shows
improved electrochemical catalytic activity with Ru doping, in which undoped MoSe2 nanoflower exhibits an
over potential of 245 mV and Tafel slope of 65 mV/dec. These values reached to minimum of 165 mV and 46
mV/dec for Mo1-xRuxSe2 of x=0.18 respectively.
70
PA-70
Fluorescent Dye-Loaded Micellar Clusters: Synthetic Strategies and Optical
Characteristics
Aleksei Solomonov1,2, Evgeniy Rumyantsev2, Yuriy Marfin2
Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
2
Inorganic Chemistry, Ivanovo State University of Chemistry and Technology, Ivanovo, Russia
1
Fluorescent organic dyes are of great interest for the wide variety of analytical and biochemical applications
due to intense and detectible respond of the molecules for characteristics of the media. However, the presence
of extended, rigid pi-electronic system leads to high hydrophobicity of fluorescent molecules decreasing its
application possibilities for biological systems where hydrophilicity is required. In this concern, we used
several synthetic strategies for obtaining of micelles loaded with hydrophobic Coumarin 6 and several dyes of
BODIPY family (boron dipyrrins) separately or in mixtures. Micellar clusters obtainment parameters were
variated to achieve desirable performance of materials. Used strategies allowed us to sufficiently increase
solubility of the dyes in aqueous media as a part of micellar clusters. Moreover the synthetic procedures
variation allowed the direct tuning of the dyes spectral characteristics by shifting of monomer-excimer (or
aggregate) equilibrium, leading to bathochromic shifts in spectra. For the first time in literature it was shown,
that dyes themselves could be used as supporting compounds for micellar clusters formation. Thus, using of the
BODIPY as cluster forming agent we drastically reduced the dyes aggregation in the micelles with maintaining
intensive fluorescence of the dye, similar results were obtained when nanoparticles of noble metals or d-metal
oxides was added to micellar systems. Nanoparticles usage imparted the magnetic properties to the micelles for
direct spatial control of clusters distribution. Presented results broadening the possibilities of fluorescent
molecules usage as a part of nanoscale micellar system.
The work was supported by the Grant of the President of the Russian Federation No. МК- 8835.2016.3 and
RFBR grants No. 16-03-01028, 15-33-20002, 15-43-03214.
71
PA-71
Colorimetric Detection of the Early Stages of Aluminum Oxidation Using
Plasmonic Gold Nano–Island Films
Alexander Tesler1, Eyal Sabatani3, Takumi Sannomiya4, Yishai Feldman2,
Alexander Vaskevich1, Israel Rubinstein1
1
Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
2
Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
3
Chemistry Division, Nuclear Research Centre Negev, Beer-Sheva, Israel
4
Materials Science & Engineering, Tokyo Institute of Technology, Yokohama, Kanagawa,
Japan
Corrosion is a natural process of degradation of metallic parts reacting with their environment, and is the major
cause of failure of metal structures in–service. Hence, detection of the early stages of environmental oxidation
of metal parts is of great importance. Here we present a colorimetric method for monitoring the surface
conditions of aluminum using the localized surface plasmon resonance (LSPR) response of gold nanoparticles
(NPs) pre–deposited onto the aluminum surface. Upon oxidation, metallic aluminum transforms to transparent
dielectric aluminum oxide (or hydroxide). In water the formed oxidation product adopts a two–layer structure:
the bottom layer is thinner and compact, while the top layer is thicker and highly porous. The gold nano–island
layer, initially deposited (by evaporation/annealing) on the aluminum surface, maintains its integrity after
corrosion in water and is located between the two aluminum oxide layers. Water oxidation of aluminum
substrates with an overlayer of plasmonic gold nano-islands leads to a pronounced color change, which can be
monitored in situ using reflection spectroscopy or colorimetrically by the naked eye. Theoretical calculations
show that the major spectral change during corrosion is attributed to the interplay between plasmonic scattering
of the Au NP layer reacting to the changing environment, and interference within the bottom aluminum oxide
layer, acting as an etalon sandwiched between the Au islands and the underlying aluminum. The top, porous
oxide layer has only a marginal contribution. The results indicate that plasmonic gold NPs are well suited for
real–time monitoring of the corrosion kinetics of aluminum and its alloys in aqueous environment and in air.
The technique is cost–effective and can be carried out in the transmission or reflection configuration.
72
PA-72
Sculpting Photocatalysts on the Nano Scale
Yifat Nakibli, Lilac Amirav
Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
The solar-driven photocatalytic splitting of water into hydrogen and oxygen is a potential source of clean and
renewable fuels. However, four decades of global research have proven this multi-step reaction to be highly
challenging. The design of effective artificial photo-catalytic systems will depend on our ability to correlate the
photocatalyst structure, composition, and morphology with its activity.
I will present our strategies, and most recent results, in taking photocatalyst production to new and unexplored
frontiers. I will focus on unique design of innovative nano scale particles, which harness nano phenomena for
improved activity, and methodologies for the construction of sophisticated heterostructures. I will share our
design rules and accumulated insights, which enabled us to obtain a perfect 100% photon-to-hydrogen
production efficiency, under visible light illumination, for the photocatalytic water splitting reduction half
reaction. Finally, I will describe our future designs of systems capable of overall water splitting and genuine
solar-to-fuel energy conversion.
73
PA-73
Platinum Free Catalysts for Hydrogen Oxidation Reaction (HOR) in Alkaline
Fuel Cells
Maria Alesker, Anya Muzikansky, Greg Gershinsky, David Zitoun
Department of Chemistry, Nanomaterials Research Center, Bar-Ilan Institute of Technology
and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan, Israel
Investigation of the hydrogen oxidation reaction (HOR) in alkaline media has been pursued in the past few
years side by side with the development of alkaline membrane fuel cells (AMFCs), also called anion exchange
membrane fuel cells (AEM-FCs). We present the synthesis, electrochemistry and AMFC test of a platinum-free
HOR catalyst. The anode catalyst is prepared by the synthesis of a tri-component nano-composite of
carbon/CNT/Carbon Mesh, palladium and an oxophilic metal (nickel), resulting in nano-dispersed,
interconnected crystalline phases of Ni and Pd. When used in the anode of a hydrogen/air AMFC, such Pd/Ni
catalyst exhibits high HOR activity, resulting in record high performance for a platinum-free AMFC.[1] The
enhancement of HOR catalytic activity vs. that observed at Pd (or Ni) alone is revealed directly in rotating disc
electrode tests of this Pd/Ni catalyst that shows a significant negative shift (200 mV) of the onset potential for
the HOR current vs. the case of Pd.[2]
[1] M. Alesker, M. Page, M. Shviro, Y. Paska, G. Gershinsky, D.R. Dekel, D. Zitoun J. Power Sources
[2] I. Bakos, A. Paszternak, D. Zitoun Electrochimica Acta, 2015, 176, 1074-1082
74
PA-74
High Capacity Silicon/Carbon-Fiber-Scaffold Anodes
Niv Aloni1, Emanuel Peled1, Diana Golodnitsky1,2
1
School of Chemistry, Tel Aviv University, Tel Aviv, Israel
2
Wolfson Applied Materials Research Center, Tel Aviv University, Tel Aviv, Israel
A major cause of capacity fading of silicon anodes is the growth of the primary and secondary SEI. Thus, space
must be allocated for this SEI growth. We report here on a novel anode structure consisting of a carbon-fiber
scaffold on which SiNPs were coated. The space between the carbon fibers enables electrolyte penetration and
SEI growth. We achieved an unprecedented combination of remarkable performance characteristics: high
loadings of 2-4mAh/cm2, a very low irreversible capacity (˜20% for the 3-4mAh/cm2 anodes), current efficiency
greater than 99%, cycle stability both in half cells and in full battery and fast charge–discharge rates (up to 1Crate). The capacity of the fiber-scaffold anode was in the range of 900 to 1400mAh/g of anode – three to four
times that of the commercial graphite anode. These anodes have been cycled for over 100 cycles, exhibiting a
stable cycle life (cells are still running). It was found that the growth in the thickness of the SEI layer and the
concomitant increase in its resistivity, represents the major reason for the observed capacity loss of the anode.
Our data reveal that the novel-architecture anode is expected to meet the requirements of lithium-ion batteries
for portable applications.
75
PA-75
Palladium based Bimetallic Electrocatalysts for Hydrogen Oxidation Reaction
in Alkaline Solution
Antony Cyril Arulrajan, Palaniappan Subramanian, Alex Schechter
Department of Chemical Sciences, Ariel University, Ariel, Israel
The H2-oxidation reaction (HOR) in alkaline medium is remarkably slower (two order of magnitude) than in
acid and its catalysis demands Pt-loadings similar to those required for the reduction of O2 in Proton Exchange
membrane Fuel Cells. In an effort to overcome this limitation with Pt, we have attempted to develop highly
active, Pt-free catalysts for HOR. We have prepared Pd-MOx (M=W or Mo) bimetallic catalysts by galvanic
displacement method and chemical reduction method. Catalyst preparations were done in de-oxygenated acidic
or alkaline solution to avoid oxide layer formation on W/Mo metal and to facilitate galvanic displacement
reaction. The Palladium based bimetallic particles were characterized by XRD, FT-IR, RAMAN, ICP-AES and
AFM and their electrocatalytic activity of these materials toward HOR was also tested and compared with
commercial catalyst and the results will be presented in this poster.
76
PA-76
Single-Wall Carbon Nanotubes Embedded in Active Masses for
High-Performance Lead-Acid Batteries
Anjan Banerjee, Baruch Ziv, Elena Levi, Yuliya Shilina, Shalom Luski, Doron Aurbach
Department of Chemistry, Bar-Ilan University, Ramat-Gan, Israel
This work reports on successful attempts to improve the performance of lead-acid batteries by the use of carbon
nanotubes as additives to the active mass of both positive and negative electrodes. Both single-wall carbon
nanotubes (SWCNT) and multi-wall carbon nanotubes (MWCNT) from commercial sources were tested. The
use of SWCNT seems to be very advantageous based on this work. Lead-acid prototype cells which electrodes
contained SWCNT showed superior performance in terms of high specific capacity, improved cycle-life, low
resistivity, better kinetics and higher rate capability. Post mortem analysis by electron microscopy and Raman
spectroscopy indicated their stability in both electrodes during prolonged cycling. Morphological, structural and
surface area analyses seemed to prove that the presence of SWCNT mitigates pronouncedly the detrimental
sulfation phenomena, namely, formation of large, inaccessible PbSO4 particles upon discharge. We suggest that
their presence in both positive and negative electrodes of these batteries increases the effective electronic
conductivity and improves the contact among the particles, thus leading to homogeneous current distribution
throughout the electrodes. We achieved specific electrodes capacities around 120 mAh g−1 and could
demonstrate 950 cycles with cells operating at 25% depth-of-discharge by adding SWCNT, while CNT-free
cells could exhibit only 90 mAh g−1 and reach only 200 cycles at the same experimental conditions.
Reference
1] J. Electrochem. Soc., 163 (8) A1518-A1526 (2016)
77
PA-77
Improving Stability of Li-Ion Batteries by Means of Transition Metal Ions
Trapping Separators
Anjan Banerjee1, Baruch Ziv1, Yuliya Shilina1, Shalom Luski1, Doron Aurbach1,
Ion C. Halalay2
1
Department of Chemistry, Bar-Ilan University, Ramat-Gan, Israel
2
General Motors R&D Center, General Motors, Warren, Michigan, USA
Transition metal ions dissolution from positive electrodes initiates a well-known degradation mechanism in Liion cells, which limits their operational life. Preventing its consequences should be considered as a
breakthrough in the field. We show herein that trapping Mn ions by ion-chelating polymers placed in the interelectrode space of cells with lithium manganate spinel (LMO) and Li or graphite electrodes, and greatly
improves their high temperature cycling performance. Mn cations trapping separators were fabricated in-house
using a commercial resin consisting of iminodiacetic acid disodium salt functional groups on a styrene
divinylbenzene polymeric matrix, either by their inclusion into a separator through a phase-inversion method or
by coating onto a plain commercial separator. We determined and compared the surface and cross-section
morphologies, electrolyte-uptake, porosity, ionic-conductivity, and electrochemical-stability of these separators
with those of a baseline separator. LMO-Li cells containing phase-inversion separators had ∼15x less Mn on
the Li-electrode than cells with the baseline separator, after 100 cycles at 55°C. LMO-graphite cells with phaseinversion separators had ∼6x less Mn on the graphite-electrode, after 100 cycles at 55°C than cells with the
baseline-separator. Capacity losses after cycling at 55°C were 30% and 55%, respectively, for the cells with
phase-inversion and baseline separators.
Reference
1] J. Electrochem. Soc.,163 (6)A1083-A1094 (2016)
78
PA-78
Electrocatalytic Carbon Dioxide Reduction in Aqueous Solutions Using
Electrodeposited Metalloporphyrin-Graphene Coatings
Yair Bochlin, Armand Bettelheim, Eli Korin
Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
The sharply rising level of atmospheric CO2 is one of the largest environmental concerns facing our civilization
today. The conversion of CO2 back to useful compounds is a critical goal that would restore balance to earth’s
atmosphere, since CO2 is the most significant greenhouse gas. CO2 reduction is possible through chemical
catalysis, electrochemistry, photochemistry and biological processes. Chemical catalytic processes generally
operate at high temperatures and pressures which lead to high energy cost. The electrochemical method,
however, operates at ambient conditions which offer a simple and effective route for CO2 reduction.
The electrocatalytic capabilities toward CO2 reduction of some cobalt porphyrins have been reported in the
literature, although at considerable overpotentials. The present work deals with the spectroscopic, microscopic
and electrochemical examination of the interactions occurring between such porphyrins and graphene
derivatives, and their effect on CO2 reduction. Such self-assembled systems which are formed between
5,10,15,20-Tetrakis(1-methyl-4-pyridinio) porphyrin (CoTMPyP) and graphene oxide (GO) were deposited on
electrode surfaces (such as glassy carbon) by means of electrodeposition. TEM images show homogeneously
distributed CoTMPyP in the graphene sheets.
The electrodeposited CoTMPyP-GO system showed increased activity for CO2 reduction vs. water reduction
(1.2 and 0.25 mA/cm2, respectively, at -1.2V vs. Ag/AgCl), as examined in aqueous 0.1 M Na2CO3 solution at
pH 11.5.
79
PA-79
A Practical Approach to Tunable Oxygen Reduction Catalysts from Mg-Based
MOFs
David Eisenberg1,2, Ning Yan1, Wowa Stroek1, Gadi Rothenberg1
Van 't Hoff Institute for Molecular Science, University of Amsterdam, Amsterdam,
Netherlands
2
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
1
Efficient oxygen reduction holds the key to practical fuel cells and metal-air batteries. Most of today’s oxygen
cathodes are based on platinum catalysts. In theory, fuel cells with such cathodes could power cars for mass
transportation – but there is simply not enough platinum on Earth to do this.
We have discovered a new family of nitrogen-doped carbons, characterized by: (1) a particularly simple
synthesis, (2) a complex and fascinating microstructure of the carbon, and (3) very good oxygen reduction
reaction (ORR) activity at pH 13.
The material is derived from the pyrolysis of easy-to-make Mg-based MOFs, with or without K+ counterions,
and yields a carbon with hierarchical micro/meso/macro porosity. This porosity results from in situ templating
by spontaneously forming MgO nanoparticles and from etching by pyrolysis gases. The mesopores are lined
with highly graphitic shells. The high ORR activity is attributed to a good balance between high specific
surface area and mass transport through the hierarchical porosity, and to improved electronic conductivity
through the graphitic shells. Importantly, its synthesis is both cheap and easily scalable.
This elegant carbon synthesis serves as a template for an entire research program in electrochemistry and
materials science, whose focus is designability of the microstructure and chemistry. Examples include tuning
nitrogen content and pore distribution, and linking it to electrocatalytic activity.
80
PA-80
Influence of Type of Carbon on ORR and OER for Sodium/Air Batteries
Evelina Faktorovich Simon2, Meital Goor Dar1, Rony Hadar1, Amir Natan2,
Diana Golodnitsky1, Emanuel Peled1
1
Chemistry, Tel Aviv University, Tel Aviv, Israel
2
Physics and Electrical Engineering and Electronics, Tel Aviv University, Tel Aviv, Israel
Sodium/air batteries have recently been studied as an alternative to lithium/air batteries. In spite of lower
theoretical specific energy (1980Wh.kg-1 of sodium vs. 3600Wh.kg-1 of lithium), the abundance of sodium
provides an advantage over lithium for its use as a metal anode.
Sodium/air batteries have a problem of the reversibility of electrode reactions similar to that of lithium/air
batteries. Applying an appropriate material as a cathode can contribute to the generation of more reversible
products on charge, increasing the cyclability and reducing ORR and OER overpotentials of the battery.
In this work, we studied ORR and OER in PEGDME500-based electrolytes, in the presence of Na+ ions,
applying four types of carbon: glassy carbon, Black Pearl, SB and XC72R carbon. For this purpose, the threeelectrode half-cell was used, utilizing the glassy-carbon electrode as the working electrode, which was tested as
a stand-alone electrode, or alternatively was coated by the carbon, with a loading of ~100µg/cm2.
It was found that, except for glassy carbon, all the other types of carbon showed very close reduction and
oxidation overpotentials. The highest reduction and oxidation currents were obtained with the use of BlackPearl carbon.
Acknowledgments
This work was funded by ISAEF and BSF foundations
81
PA-81
Metal-Organic Frameworks as an Enzyme-Inspired Heterogeneous Platform
for Electrocatalytic CO2 Reduction
Idan Hod
Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
In a world that is running out of natural resources, there is a growing need to design and develop sustainable
and green energy resources. In that respect, electrochemically driven reduction of CO2 to form liquid alternative
fuels holds the potential to provide a route for future carbon neutral energy economy. Nevertheless, the slow
kinetics of this catalytic reaction demands the development of efficient catalysts in order to drive it at lower
overpotentials. Indeed, a variety of molecular catalysts based on metal complexes are capable of
electrochemically reducing CO2. Yet, despite the significant progress in this field, practical realization of
molecular catalysts will have to involve a simple and robust way to assemble high concentration of these
catalysts in an ordered, reactant-accessible fashion onto a conductive electrode.
Our group utilizes Metal-Organic Frameworks (MOFs) as a platform for heterogenizing CO2 reduction
molecular catalysts. Their unique properties (porosity and flexible chemical functionality), enables us to use
MOFs for integrating all the different functional elements needed for efficient catalysts: 1) immobilization of
molecular catalysts, 2) electron transport elements, 3) mass transport channels, and 4) modulation of catalyst
secondary environment. Thus, in essence, MOFs could possess all of the functional ingredients of a catalytic
enzyme.
In this talk, I will present our recent proof-of-principle study on electrocatalytic CO2 reduction activity of
MOFs incorporating molecular catalysts such as Fe-tetraphenylporphyrin and Mn(bpy)(CO)3Br.
82
PA-82
Vertically Aligned Molybdenum Disulfide for Efficient Lithium Storage
Victor Shokhen1, Yana Miroshnikov1, Gregory Gershinsky1, Noam Gotlib2, Chen Stern2,
Doron Naveh2, David Zitoun1
1
Chemistry Nanotechnology and Advanced Materials (BINA), Bar-Ilan University,
Ramat-Gan, Israel
2
Faculty of Engineering, Bar-Ilan University, Ramat-Gan, Israel
Layered transition-metal disulfides (LTMDs) have played a prominent role in the development of electronic,
energy conversion and storage devices. Molybdenum disulfide (MoS2) has been widely investigated as a highly
efficient alternative to existing materials. Most fabrication pathways of MoS2 focus on its planar growth on
various substrates to reach high-quality layers with planar orientation (PO). Nevertheless, in most energystorage applications, the most relevant orientation is the vertical alignment (VA) of well-defined layers. VA
growth paves the way to highly dense devices with exposed active sites on the surface. Here, the chemical
vapor deposition (CVD) process has been investigated to grow 2H-MoS2 films hundreds of nanometers thick
with VA stacking. The films show large domains of perfectly aligned layers with high crystallinity and density
and low surface roughness. CVD-grown VA-MoS2 films show superior behavior in lithium storage, with stable
capacity even at a high current density compared to PO-MoS2 films. The VA-MoS2 films show a high
reversible capacity of 800 mAh/g for lithium storage, which corresponds to the full conversion to Mo and Li2S.
HR-TEM images of VA-MoS2 Capacity of VA-MoS2 compare to PO-MoS2
83
PA-83
Tailoring the Electronic Structure of Te/Y-doped NbBiO4 using Oxygenvacancy for All-oxide PV Application: A Theoretical and Experimental Study
Vijay Singh, Susanta Das, David Keller, Dan Thomas Major
Department of Chemistry, Bar-Ilan University, Ramat-Gan, Israel
First principles studies of point defects and impurities in semiconductors, insulators and metals have become an
integral part of material research over the last few decades.1 Point defects and impurities often have decisive
effects on material properties.2, 3 Recently, using density functional theory (DFT) calculations we have revealed
that Bi2O3 is a low band-gap material and the obtained energy band-gap, 2.30 eV, lies in the region of PV
interest. The observed optical transitions between the valence band (VB) (O-2p states) and the conduction band
(CB) (Bi-6p states) are not allowed due to violation of the dipole selection rule (Δl =+/-1). Therefore, Bi2O3 is
not a potential absorber material for photovoltaic (PV) applications. With the aid of DFT calculations and
experimental measurements, we have also studied the NbBiO4 system extensively, and our results revealed that
its valence band (VB) and conduction band (CB) consist of optically active states, but its large energy band gap,
3.50 eV, puts a constraint on its use as an absorber material. In the present talk, I shall discuss how, with the
help of suitable doping as well as oxygen vacancy, we managed to reduce the energy band gap of NbBiO 4, from
3.50 eV to 2.20 eV without changing its electronic structure. The observed band-gap is in the region of PV
interest and transitions between the CB and VB states are optically allowed. Using COHP (energy resolved
visualization of chemical bonding) calculations, we revealed that Y doping in NbBiO4 significantly reduces the
covalent bonding between Bi and nearest neighbors oxygen ions from 1.00 eV/bond to 0.10 eV/bond. As a
consequence, the computed oxygen defect formation energies for Y-doped NbBiO4 system is lower than the
oxygen defect formation energies of the pure NbBiO4 system, contributing to a large oxygen-defect
concentration. Thus, the significance of oxygen vacancy in Y-doped NbBiO4 (Y@Bi site only) was revealed
and this study might serve to design better PV absorber materials in the future.
References
1] Freysoldt, C.; Grabowski, B.; Hickel, T.; Neugebauer, J.; Kresse, G.; Janotti, A.; Van de Walle, C.
G., First-principles calculations for point defects in solids. Rev. Mod. Phys. 2014, 86, 253-305.
2] Ganguli, N.; Dasgupta, I.; Sanyal, B., Electronic structure and magnetism of transition metal doped
Zn12O12 clusters: Role of defects. J. Appl. Phys. 2010, 108, 123911.
3] Yavo, N.; Smith, A. D.; Yeheskel, O.; Cohen, S.; Korobko, R.; Wachtel, E.; Slater, P. R.;
Lubomirsky, I., Large Nonclassical Electrostriction in (Y, Nb)‐ Stabilized δ‐ Bi2O3. Adv. Funct. Mater.
2016.
84
PA-84
Using DFT as a Guiding, Predicting and Explanatory Tool for the Study of
Ruthenium based Olefin Metathesis Catalysts
Alexander Frenklah, Sebastian Kozuch, Gabriel N. Lemcoff
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
Research spanning various DFT methodologies is a major part in many leading research groups around the
globe, especially in catalysis. Thus, DFT calculations grow more efficient and can be adapted to perform high
accuracy calculations for an array of chemical systems and phenomena. One can predict that before long,
skilled experimentalists will use DFT as a complementary tool parallel to NMR, MS or any other
characterization and analysis means. Publications1 concerning ruthenium olefin metathesis catalysts, disclosing
complementary experimental and calculated data are quite common; on the one hand results obtained from
experimental work are empowered by theoretical analysis, on the other, and much more attractive, the
theoretical predictions may lead to the development of new catalysts and properties which had escaped the
insight of the experimentalists. Herein, two distinctive studies carried out in our group blending DFT and
experimental research.
The first work deals with the nature of the anionic ligands in ruthenium pre-catalysts designed for asymmetric
olefin metathesis.2 DFT calculation were utilized to try to elucidate surprising results obtained while
performing anionic ligand exchange in certain ruthenium complexes.
In a separate work, DFT was used to calculate the energy differences between cis/trans isomers with differing
carbene ligands. This work is a part of a wider exploration on the influence of (cyclic alkyl amino carbene)
CAAC sulfur – chelated ruthenium precatalysts for olefin metathesis.3
References:
1] Falivene, L.; Poater, A.; Cazin, C. S. J.; Slugovs, C.; Cavallo, L. Dalton.Trans. 2013, 42, 7312
2] Ivry, E.; Lemcoff, N. G.; unpublished
3] Rosenberg, I.; Lemcoff, N. G.; unpublished
85
PA-85
Origin and Structure of Polar Domains in Doped Molecular Crystals*
Ido Azuri1, Elena Meirzadeh1, Yubo Qi2, David Ehre1, Andrew M. Rappe2, Meir Lahav1,
Leeor Kronik1, Igor Lubomirsky1
1
Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
2
The Makineni Theoretical Laboratories, Department of Chemistry,
University of Pennsylvania, Philadelphia, Pennsylvania, USA
Doping is a primary tool for the modification of the properties of materials. Occlusion of guest molecules in
crystals generally reduces their symmetry by the creation of polar domains, which engender polarization and
pyroelectricity in the doped crystals. Here we describe a molecular-level determination of the structure of such
polar domains, as created by low dopant concentrations (0.5%). The approach comprises crystal engineering
and pyroelectric measurements, together with dispersion-corrected density functional theory and classical
molecular dynamics calculations of the doped crystals, using neutron diffraction data of the host at different
temperatures. This approach is illustrated using centrosymmetric α-glycine crystals doped with minute amounts
of different L-amino acids. The experimentally determined pyroelectric coefficients are explained by the
structure and polarization calculations, thus providing strong support for the local and global understanding of
how different dopants influence the properties of molecular crystals.
*Nature Comm., 7, 13351 (2016)
86
PA-86
Ab-initio First Principle Investigations of Molybdenum Carbide Supported Pt
Catalyst
Chethana Bhadravathi Krishnamurthy, Oran Lori, Lior Elbaz, Ilya Grinberg
Department of Chemistry, Bar-Ilan University, Ramat-Gan, Israel
Platinum nanorafts on molybdenum carbide support have been found to be an excellent electrocatalyst for the
oxygen reduction reaction (ORR) and show enhanced performance in proton exchange membrane fuel cells
(PEMFCs). We use first-principles psuedopotential plane-wave calculations to describe the formation of Pt
nano rafts and their ORR catalytic activity on β-Mo2C. Our simulations demonstrates that Pt adsorbs strongly
on the C atom of the β-Mo2C surface with the adsorption energy of 7.18 eV that is larger than the values found
for other absorption sites on the β-Mo2C surface. Subsequent addition of Pt atoms on the β-Mo2C surface
reduces the adsorption energy to 5.90 eV. This is still significantly higher than the cohesive energy of bulk Pt
(5.3 eV). As a result, Pt prefer to forms a sheet-like structure on the β-Mo2C support instead of agglomerating
into particles, leading to the formation of catalytically active and stable Pt nanorafts, in agreement with the
experimental reports. Our calculations also show that the adsorption and dissociation of oxygen is slightly more
difficult on Pt nanorafts than on the bare Pt surface, as indicated by the higher dissociative O adsorption energy.
The dissociative O adsorption energy of the-Mo2C supported Pt is closer to the peak of the volcano curve than
that for the unsupported Pt surface. Thus, the Pt nano rafts on β-Mo2C are found to be catalytically more active
for ORR than the Pt nanoparticles.
87
PA-87
Bitter or Not? BitterPredict- Tool for Predicting Taste from Chemical
Structure
Ayana Dagan-Wiener1,2, Masha Y. Niv1,2
Institute for Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of
Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
2
Fritz Haber Center for Molecular Dynamics, The Hebrew University of Jerusalem, Jerusalem,
Israel
1
Bitter taste is a significant factor in animal’s choice of food. Animals avoid eating bitter food components,
many of which are toxic. Nevertheless, it is known today that bitterness is not always noxious and that some of
the bitter compounds have beneficial effects on health. Interestingly bitter taste receptors are also expressed in
many extraoral tissues and emerge as novel targets for therapeutic indications such as asthma and infection.
Bitter compounds (gathered in the BitterDB http://bitterdb.agri.huji.ac.il/dbbitter.php) dramatically vary in their
structures. Therefore, identifying bitter molecules based on their chemical structures is a very challenging task.
Here we present a machine learning classifier, BitterPredict, which predicts whether a molecule is bitter or not,
based solely on its chemical structure. To this end we used: BitterDB as the true positives set, non-bitter
molecules that were gathered from literature and enriched by random molecules as true negative set,
physicochemical and ADME/TOX descriptors for the molecules, and Adaboost (decision tree based) algorithm.
BitterPredict correctly classifies over 85% of the compounds in the hold-out test set, and between 70% to 90%
of the compounds in three independent external sets. The fraction of sp3-hybridized (tetrahedral) carbon atoms
out of total carbon count (Fsp3) and Hydrophobic component of the saturated carbon and attached hydrogen
(FOSA) descriptors are the most important contributors to the classifier.
Interestingly, but not surprisingly, the classifier suggests that a small portion (10%) of compounds found in
food, and a large portion (70%) of clinical and experimental drugs, are bitter.
88
PA-88
Mars-van-Krevelen Mechanism in Anaerobic and Aerobic Reaction of
Bimetallic Polyoxometalates: Theory and Experiment in Concert
Irena Efremenko, Ronny Neumann, Jan M. L. Martin
Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
Molecular oxygen is a very attractive oxidant for most industrially important reactions. However, its direct
interaction with organic compounds, particularly in oxidation of hydrocarbons, is characterized by low
selectivity and tendency to over-oxidation. Selective liquid phase activation and oxidation of hydrocarbons
could be achieved in presence of polyoxometalates. In such reactions, substrates are dehydrogenated or
oxygenated by oxygen atoms from the catalyst bulk, and then the reduced catalyst is reoxidized by molecular
oxygen. This spatiotemporal separation between the substrate oxidation and the catalyst regeneration is
responsible for high selectivity of such reactions.
It has been shown that phosphovanadomolybdates, notably the H5PV2Mo10O40 polyoxometalates of the αKeggin structure, conduct oxidative dehydrogenation and oxygenation of various substrates by an electron
transfer−oxygen transfer type mechanism. There are three key steps to these reactions: (1) initiation of substrate
activation by electron transfer (ET) to the polyoxometalate; (2) a sequence of reactions leading to
dehydrogenation of the substrate or to oxygen transfer from the polyoxometalate to the substrate with formation
of the oxygenated product; and (3) the reoxidation of the reduced catalyst with O2.
In this presentation, we will discuss our recent results on the mechanisms of oxygenation and oxidative
dehydrogenation of strong sp2- and sp3-C-H bonds in anaerobic conditions followed by aerobic reoxidation of
the reduced polyoxometalates. While an outer-sphere mechanism of the reoxidation reaction is possible for
several polyoxometalates, we will show that both reduction and oxidation of phosphovanadomolybdates follow
the Mars-van-Krevelen mechanism typical for solid metal oxides.
89
PA-89
Biogenic Twinned Crystals Exhibiting Unique Morphological Symmetry
Anna Hirsch1, Dvir Gur2, Benjamin Palmer2, Steve Weiner2, Lia Addadi2, Leslie Leiserowitz1,
Leeor Kronik1
1
Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
2
Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
Guanine crystals are widely used in nature as components of multilayer reflectors. Organisms control the size,
morphology, and arrangement of these crystals, to obtain a variety of optical “devices” [1]. The reflection
systems found in the lens of the scallop eye and in the copepod cuticle are unique in that the multilayered
reflectors are tiled together to form a contiguous packed array. In the former, square crystals are tiled to form a
reflecting mirror. In the latter, hexagonal crystals are closely packed to produce brilliant colors. Based on
electron diffraction, morphology considerations, and density functional theory, these crystals were shown to
possess similar monoclinic crystal symmetry, which we have previously identified as different from that of
synthetic anhydrous guanine [2]. However, the crystals are different in that multiple twinning about the {012}
and the {011} crystallographic planes results in square and hexagonal morphology, respectively. This is a
unique example where controlled twinning is used as a strategy to form a morphology with higher symmetry
than that of the underlying crystal, allowing for tiling that facilitates optical functionality.
[1] D. Gur, B. Palmer, S. Weiner and L. Addadi, "Light Manipulation by Guanine Crystals in Organisms:
Biogenic Scatterers, Mirrors, Multilayer Reflectors and Photonic Crystals", Advanced Materials (2016), in
press.
[2] A. Hirsch, D. Gur, I. Polishchuk, D. Levy, B. Pokroy, A. J. Cruz-Cabeza, L. Addadi, L., and Leslie
Leiserowitz, “Guanigma”: The Revised Structure of Biogenic Anhydrous Guanine, Chemistry of Materials,
2015, 27 (24), 8289-8297
90
PA-90
Factors Impacting the Accuracy of C NMR Chemical Shift Predictions using
Density Functional Theory – The Advantage of Long-Range Corrected
Functionals
13
Mark A. Iron
Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
Nuclear magnetic resonance (NMR) is an indispensible tool in organic, organometallic and inorganic
chemistry. Its use is key in determining structure of compounds – including stereochemistry – and in following
reactions. On occasion, however, it is not always definitive, and the actual structure may be debated. The use of
calculated chemical shifts is becoming indespensible in helping resolve the structure, yet sometimes the results
can be either inconclusive or even incorrect.
There have been a number of studies published each looking at the impact of certain factors on the accuracy of
the calculated chemical shifts. Here, an in-depth study is presented where the key factors are considered:
exchange-correlation functional – where over 70 are considered, basis set, integration grids, and the NMR
calculation method. For the first time (to the best of my knowledge), long-range corrected functionals were
considered and are shown to be more accurate than other functionals.
Recently, Smith and Goodman proposed the DP4 probability as a reliable tool in selecting which amongst a set
of potential structures is the most likely based on comparison of the calculated and experimental NMR spectra.
This method has found significant use in the determination of the stereochemistry of natural products with
several chiral centres. The parameters for DP4 were determined for the method of choice found in this study.
91
PA-91
Catalytic Action of Cobalt (II) Peroxomonosulfate Complexes in Fenton-like
Reactions – Computational Research Using Density Functional Theory
Dmitri Katsaran, Haya Kornweitz
Biological Chemistry Department, Ariel University, Ariel, Israel
Fenton reaction was observed more than 120 years ago, nevertheless it still remains in the center of an
extensive scientific research. The question regarding the mechanism of the Fenton and Fenton-like reactions
and the nature of the oxidizing species obtained has been just partially revealed as each catalytic system has its
own specifications.
A large number of Fenton-like catalytic systems has been learned, while the last publications[1,2] of Dan
Meyerstein research group concerning CoII(aq)/H2O2 system (pure and combined with bicarbonate ion as coenzyme) present a new interesting root of the mechanism. The system reacts by coordination of number of
ligands to the central cation before releasing oxidizing species, which may appear as hydroxyl radical or as
bicarbonate radical.
Our research is focused on CoII(aq)/HSO5-(aq) system, which has many well-known applications in wastewater
treatment. The system`s components suggest an integration of the forms of hydrogen peroxide and bicarbonatelike co-catalyst in peroxomonosulfate ion.
The search for plausible reaction mechanism has been performed on the basis of quantum-mechanical
calculations on density functional level of theory using B3LYP/6-311+G(d,p)/SMD model.
At this stage, the following reaction mechanism key features can be pointed out:
1] Cyclic coordination of peroxomonosulfate ion (simultaneously through peroxy oxygen and sulfite
oxygen atoms) to cobalt (II) complex.
2] Coordination (cyclic or through the peroxy oxygen atom) of the second peroxomonosulfate ion.
3] Formation of sulfate radical through homolytic cleavage of peroxy bond in one of the
peroxomonosulfate ligands attached to cobalt (II) complex.
References:
- Burg A., Shusterman I., Kornweitz H. and Meyerstein D., Dalton Trans., 2014, 43, 9111-9115
- Burg A., Shamir D., Shusterman I., Kornweitz H. and Meyerstein D., Commun., 2014, 50, 1309613099
92
PA-92
The S66x8 Benchmark for Noncovalent Interactions Revisited: Explicitly
Correlated Ab Initio Methods and Density Functional Theory
Manoj K. Kesharwani1, Brina Brauer1, Sebastian Kozuch2, Jan M. L. Martin1
Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
2
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
1
The S66x8 dataset for noncovalent interactions of biochemical relevance has been re-examined by means of
MP2-F12 and CCSD(F12*)(T) methods. We deem our revised benchmark data to be reliable to about 0.05
kcal/mol RMS. Most levels of DFT perform quite poorly in the absence of dispersion corrections: somewhat
surprisingly, that is even the case for the double hybrids and for dRPA75. Analysis of optimized D3BJ
parameters reveals that the main benefit of dRPA75 and DSD double hybrids alike is the treatment of midrange
dispersion. dRPA75-D3BJ is the best performer overall at RMSD=0.10 kcal/mol. The nonlocal VV10
dispersion functional is especially beneficial for the double hybrids, particularly in DSD-PBEP86-NL
(RMSD=0.12 kcal/mol). Other recommended dispersion-corrected functionals with favorable
price/performance ratios are ωB97X-V, and, surprisingly, B3LYP-D3BJ and BLYP-D3BJ (RMSDs of 0.23,
0.20 and 0.23 kcal/mol, respectively). Without dispersion correction (but parametrized for midrange
interactions) M06-2X has the lead (RMSD=0.45 kcal/mol). A collection of three energy-based diagnostics
yields similar information to an SAPT analysis about the nature of the noncovalent interaction. Two of those
are the percentages of Hartree-Fock and of post-MP2 correlation effects in the interaction energy; the third,
CSPI=[IEss(2)–IEab(2)]/[IEss(2)+IEab(2)] or its derived quantity DEBC=CSPI/(1+CSPI2)1/2, describes the character
of the MP2 correlation contribution, ranging from 0 (purely dispersion) to 1 (purely other effects). In addition,
we propose an improved, parameter-free scaling for the (T) contribution based on the Ecorr[CCSDF12b]/Ecorr[CCSD] and Ecorr[CCSD(F12*)]/Ecorr[CCSD] ratios. For Hartree-Fock and conventional DFT
calculations, full counterpoise generally yields the fastest basis set convergence, while for double hybrids, halfcounterpoise yields faster convergence, as previously established for correlated ab initio methods.
93
PA-93
Nanotubes Motion on Layered Materials: A Registry Perspective
Inbal Oz, Itai Leven, Yaron Itkin, Asaf Buchwalter, Katherine Akulov, Oded Hod
Department of Chemistry, Tel Aviv University, Tel Aviv, Israel
Abstract At dry and clean material junctions of rigid materials the corrugation of the sliding energy landscape is
dominated by variations of Pauli repulsions. These occur when electron clouds centered around atoms in
adjacent layers overlap as they slide across each other. In such cases there exists a direct relation between
interfacial surface (in)commensurability and superlubricity, a frictionless and wearless tribological state. The
Registry Index is a purely geometrical parameter that quantifies the degree of interlayer commensurability, thus
providing a simple and intuitive method for the prediction of sliding energy landscapes at rigid material
interfaces. In the present study, we extend the applicability of the Registry Index to non-parallel surfaces, using
a model system of nanotubes motion on flat hexagonal materials. Our method successfully reproduces sliding
energy landscapes of carbon nanotubes on Graphene calculated using a Lennard-Jones type and the
Kolmogorov-Crespi interlayer potentials. Furthermore, it captures the sliding energy corrugation of a boron
nitride nanotube on hexagonal boron nitride calculated using the h-BN ILP. Finally, we use the Registry Index
to predict the sliding energy landscapes of the heterogeneous junctions of a carbon nanotubes on hexagonal
boron nitride and of boron nitride nanotubes on graphene that are shown to exhibit a significantly reduced
corrugation. For such rigid interfaces this is expected to be manifested by superlubric motion.
94
PA-94
Development in the DFT Estimates of Magnetic Couplings in ChromiumBased Molecular Rings from an Optimally-Tuned Range separated Hybrid
Functional
Shira Weissman1, Michal Antkowiak2, Grzegorz Kamieniarz2, Leeor Kronik1
1
Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel
2
Faculty of Physics, A. Mickiewicz University, Poznan, Poland
The Cr8 molecule, as well as its homo- and hetero-metallic derivatives, belongs to a class of molecular
nanomagnets which are extensively studied for a number of fundamental aspects and envisaged applications.
However, estimating accurately their magnetic couplings from first principles calculations has proven to be
difficult. Here we present progress in this area for two prototypical molecular rings, Cr8 and Cr7Ni-, using
density functional theory with an optimally-tuned range separated hybrid (OT-RSH) functional. This approach
has been shown to allow for an accurate description of the electronic structure in a variety of more simple
molecular systems. Here, we show that it is also capable of producing highly accurate magnetic exchange
parameters for both molecules despite their complexity, while improving the overall description of the
electronic structure, especially with respect to the energy of the frontier orbitals. For the Cr 7Ni- ring, the values
of the magnetic couplings found are distinguished by a unique site distribution and lead to excellent agreement
with experiment.
95
PA-95
Directed Assembly of Nano Particles by a Modulated Photo-Induced
Microbubble
Nina Armon1, Udi Greenberg1, Michael Layani2, Shlomo Magdassi2, Hagay Shpaisman1
1
Chemistry Department, Institute for Nanotechnology and Advanced Materials,
Bar-Ilan University, Ramat-Gan, Israel
2
Casali Center for Applied Chemistry, Institute of Chemistry,
The Hebrew University of Jerusalem, Jerusalem, Israel
The laser induced microbubble technique (LIMBT) has been previously demonstrated for assembly of various
materials. The principle of this method is that a microbubble formed by laser heating leads to material
deposition at the bubble/substrate interface. Moving the focused beam relative to the sample results in the
migration of the microbubble and constant deposition of additional material. The major limitation of this
technique is its instability, resulting in non-continuous deposition.
Here we show how modulation of the laser, thus controlling the construction and destruction rate of the
microbubble, allows formation of significantly thinner and more continuous patterns. We verify the continuity
of the formed patterns by measuring the conductance of deposited metallic nanoparticles.
We furthermore apply this improved technique to construct more complex structures than previously possible
using metals, oxides, polymers and various combinations of the former (hybrid structures). This exemplifies the
ability of this method to be used for various foreseen applications such as transparent conductors and sensors.
96
PA-96
Enantioselective Reactions on Chirally-Modified Model Surfaces: A New
Molecular Beam/Surface Spectroscopy Apparatus
1
Smadar Attia1, Evan J. Spadafora2, Hans J. Freund1, Swetlana Schauermann2
Department of Chemical Physics, Fritz Haber Institute of the Max Planck Society, Berlin,
Germany
2
Institute of Physical Chemistry, Christian Albrechts University of Kiel, Kiel, Germany
A molecular-level understanding of enantioselective processes on chiral surfaces is an important prerequisite
for the rational design of new enantiospecific catalysts. Therefore, in this study, the reaction mechanisms,
kinetics and dynamics of surface reactions were investigated using multi-molecular beam techniques and in-situ
surface spectroscopic and microscopic tools on well-defined model surfaces in UHV.
A new UHV apparatus consisting of two independent UHV systems for the preparation and characterization of
chirally modified model catalysts has been designed and built. This apparatus comprises three molecular beams
(two effusive and one supersonic molecular beam), infrared reflection absorption spectroscopy (IRAS) as well
as a number of standard tools for preparation and characterization of model surfaces, both single crystals and
nanostructured surfaces consisting of metal nanoparticles supported on thin oxide films. Additionally, the
sample can be transferred to an independent unit containing scanning tunneling microscope (STM).
First experiments were carried out at the newly setup UHV apparatus to investigate adsorption and reactivity
behavior of a model chiral modifier (R)-(+)-1-(1-Naphthyl)ethylamine (NEA) and a prochiral molecule
acetophenone over Pt(111). These processes were investigated over a broad range of coverage and temperature
conditions. NEA was found to homogeneously distribute over Pt(111) surface at low coverage and to build
island-like structures in the high coverage regime. Currently, co-adsorption of NEA with acetophenone is
investigated with STM to follow the formation of NEA-acetophenone complexes on this chirally modified
surface.
Spectroscopically, acetophenone was observed to strongly interact with the pristine Pt(111) surface resulting in
strong changes of the IR spectra as compared to the unperturbed molecules in multilayers. Further experiments
are currently in progress.
97
PA-97
Catalytic Formation of C-N Bond by Direct Condensation Between
Non-Activated Amines and Alcohols
Marco Fabbiani2, Veronica Bottero1, Erica Rebba1, Ettore Fois2, Piero Ugliengo1,
Gianmario Martra1
1
Department of Chemistry, University of Torino, Torino, Italy
2
Department of Science and High Technology, Univeristy of Insubria, Como, Italy
C-N bond forming cross-coupling reactions in a “atom economy” regime is among emerging issues in fine
chemistry in order to attain highly sustainable processes. [1] As an innovative contribution in this field, the
possibility to use amorphous silica as a catalyst able to promote the condensation between non-activated
secondary amines and primary or secondary alcohols was carried out. Two types of commercial pyrogenic
silicas (AEROSIL OX 50 and AEROSIL 300, by EVONIK), exhibiting two different density of surface silanols
(1.4 and 5.1 OH/nm2, respectively) were used as catalyst. Before the contact with reagents silicas were simply
outgassed at room temperature under high vacuum, these treatments resulting in the complete removal of water
molecules from their surface (as checked by in situ IR spectroscopy). Diethyl amine was then adsorbed on the
catalyst and then the systems were contacted with ethanol or iso-propyl alcohol at room temperature. Once
reached the equilibrium, a consumption of the amine nNH band was observed (by IR) and the formation of the
expected products (triethyl amine or diethyl-N-isopropyl amine) were detected by HR-MS analysis of the
solutions resulting from water washing of the reacted samples. Thus, silicas might be considered as potential
catalyst for this kind of condensation reaction, in addition to the already known catalytic activity exhibited
towards the formation of amides from non-activated carboxylic acids and amines, in actual catalytic tests. [2]
References
[1] Bariwal J., Van der Eycken E. Soc. Rev. 2013, 42, 9283.
[2] Comerford J.W., Clark J.H., Macquarrie D. J., Breeden S. W. Commun. 2009, 2562.
98
PA-98
Formation of Homo- and Hetero- Peptides by Condensation of Non-Activated
Amino Acids on Oxides: from Prebiotic to Fine Chemistry
Marco Fabbiani2, Veronica Bottero1, Erica Rebba1, Rossella Arletti3, Piero Ugliengo1,
Gianmario Martra1
1
Department of Chemistry, University of Torino, Torino, Italy
2
Department of Science and High Technology, University of Insubria, Como, Italy
3
Department of Earth Science, University of Torino, Torino, Italy
The formation of peptides from non-activated amino acids on mineral surfaces was likely among the prebiotic
chemical events relevant for the origin of life [1]. Noteworthy, abiotic-like conditions can be a proof of
principle of the occurrence of reactions in a “atom economy” regime. Indeed, the issues of reagent waste and
cost associated with amide bond formation are among hot topics in fine chemistry. Catalysed reactions are quite
attractive for this purpose, and an ambitious step ahead would be catalytic solvent-free syntheses of
polypeptides from non-activated amino acids. In this respect, the effectiveness of TiO2 and SiO2 nanoparticles
in promoting the formation of long poly-Gly was recently demonstrated [2]. Key aspects of the model
experimental conditions were the initial removal of water adsorbed from the catalyst, the admission of amino
acid molecules on the catalyst from the vapour phase (by sublimation) and the removal of water produced
during the reaction.
This was the first observation of the sequential occurrence of (i) the catalytic formation of polypeptides up to 16
units long and (ii) the self-assembling of the formed polypeptides into closely packed aggregates containing
both helical and β-sheet-like patches [2]. The investigation was then extended to Ala and to the possibility to
produce (-Gly)n-(Ala)m hetero-polypeptides. Insights on the amide bond formation mechanism were obtained
experimentally for TiO2 as catalyst, and by molecular modelling for the reaction occurring on SiO2.
References
[1] Ferris, J. P.; Hill, A. R.; Liu, R. H.; Orgel, L. E. Nature, 1996, 381, 59-61.
[2] Martra, G.; Deiana, C.; Sakhno, Y.; Barberis, I.; Fabbiani, M.; Pazzi, M.; Vincenti, M. Angewandte Chemie
International Edition, 2014, 53, 4671-4674.
99
PA-99
Scanning Tunneling Microscopy and Spectroscopy of Novel Silver-Containing
DNA Molecules
Natalie Fardian-Melamed1, Gennady Eidelshtein2, Roman Zhuravel1, Dvir Rotem1,
Alexander B. Kotlyar2, Danny Porath1
1
Institute of Chemistry and Center for Nanoscience and Nanotechnology,
The Hebrew University of Jerusalem, Jerusalem, Israel
2
Department of Biochemistry, Tel Aviv University, Tel Aviv, Israel
The quest for a suitable molecule to pave the way to molecular nano-electronics has been met with obstacles for
over a decade. Candidate molecules such as carbon nanotubes lack the appealing trait of self-assembly, while
DNA lacks the desirable feature of conductivity. Silver-containing poly(G)-poly(C) DNA (E-DNA1) molecules
were recently reported as promising candidates for molecular electronics, owing to the selectivity of their
metallization, their uniform structure, their stability, their resistance to deformation, and their most possible
conductivity. Here we present an elaborate temperature dependent high-resolution morphology characterization
of these unique molecules, alongside a detailed depiction of their electronic level structure. Our findings were
acquired by use of an ultra-high vacuum (UHV) scanning tunneling microscope (STM). The energy levels
found for E-DNA indicate a novel, truly hybrid metal-molecule structure. These findings2 add substantially to
our knowledge about E-DNA molecules, leading to a further understanding of these molecules’ conductive
properties, bringing about their attractiveness as nanowires.
1. Eidelshtein G, Fardian‐ Melamed N, Gutkin V, Basmanov D, Klinov D, Rotem D, Levi‐ Kalisman Y,
Porath D, Kotlyar A. Synthesis and Properties of Novel Silver‐ Containing DNA Molecules. Advanced
Materials. 2016.
2. Fardian-Melamed N, Eidelshtein G, Zhuravel R, Rotem D, Kotlyar A, Porath D. Scanning Tunneling
Microscopy and Spectroscopy of Novel Silver-Containing DNA Molecules. (In Preparation).
100
PA-100
Strategies for Improving Quantitative NMR Diffusion and Relaxation
Measurements
Roy Hoffman
Department of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
Diffusion and magnetic nuclear relaxation are important for the study of molecular motion and structure,
paramagnetism, solution dynamics, and resolution of mixtures.
Thermal convection and radiofrequency (rf) inhomogeneity adversely affect the accuracy of diffusion and
relaxation. Rf inhomogeneity leads to partial excitation of signals in sections of the sample leading to
incomplete refocusing and distortion of relaxation decays and diffusion intensities. Convection, combined with
rf inhomogeneity leads to nuclei being excited then being transported to a region with different rf and gradient
intensity before a refocusing pulse is applied, increasing the apparent decay rate.
The intensity of signals in a DOSY experiments are strongly influenced by relaxation. To obtain a quantitative
determination of the amount ofmixture components, DOSY must be combined with relaxation measurements.
Quantitative DOSY is especially sensitive to rf inhomegeneity and convection. The use of spacially volumerestricted samples improves the accuracy by improving rf homogeneity and reducing thermal convection.
101
PA-101
Dynamic Nuclear Polarization in Solid Samples by Electrical-DischargeInduced Radicals
Itai Katz, Aharon Blank
Department of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
Dynamic nuclear polarization (DNP) is a method for enhancing nuclear magnetic resonance (NMR) signals
with many potential applications in chemistry and medicine. Traditionally, DNP signal enhancement is
achieved through the use of exogenous stable free-radicals mixed in a solution with the molecules of interest,
resulting in a process that changes the Boltzmann population of the nuclear spins’ energy levels. Many solid
materials, however, cannot tolerate wetting (such as various pharmaceuticals), and thus pose a challenge to
current DNP sample preparation protocols. Here we show that proton DNP signal enhancements can be
obtained for solid samples without the use of solvent and exogenous free-radicals [1]. This is achieved by the
use ionized gas to generate radicals primarily on the surface of a solid sample. These radicals are found suitable
for DNP of various solid samples. The plasma-induced radicals are stable under moderate vacuum conditions,
yet can be readily eliminated from the sample by introduction of a solvent. The latter property can be of high
importance for medical imaging applications, where there is a strong need for generating highly polarized
metabolites, without the use of the potentially harmful stable free radicals.
[1] Journal of Magnetic Resonance – 261, (2015) 95-100
102
PA-102
Spin-Dependent Electrochemistry without Magnet
Anup Kumar1, Eyal Capua1, Claudio Fontanesi2, Ron Naaman1
1
Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
2
Department of Chemical and Geological Science, University of Modena and Reggio Emilia,
Modena, Italy
Chiral Induced Spin Selectivity (CISS) effect demonstrates the preferential transport of one spin orientation of
the electrons through the chiral molecules.1 Hence, the production of an effective local magnetic field on a
nanometric scale can be achieved.2 We report a quantitative study of spin accumulation as a function of current
passing through chiral molecule in a conventional electrochemical cell, when the working electrode is made
from gallium nitride (GaN). Chiral molecules are adsorbed on the GaN surface). The spin
accumulation/magnetic field is monitored applying a Hall setup made on top of the working electrode. 3 The
strength and direction of the magnetic field measured correlates with the spin preference for electrons
transmitted through the adsorbed chiral layer.
Figure 1: Set-up for simultaneous spin-dependent electrochemistry/Hall potential measurement on GaN device.
References
1. Naaman, R., and Waldeck D., J. Phys. Chem. Lett, 2012, 3, 2178-2187.
2. Ben Dor, O., Morali, N., Yochelis, S., Baczewski, L. T. and Paltiel, Y., Nano Lett. 2014, 14, 6042–6049.
3. Eckshtain-Levi, M.; Capua, E.; Refaely-Abramson, S.; Sarkar, S.; Gavrilov, Y.; Mathew, S. P.; Paltiel, Y.;
Levy, Y.; Kronik, L. and Naaman, R., Nature Comm. 2016, doi: 10.1038/ncomms10744.
103
PA-103
Aspen Tree Protein SP1 as a Biological Nanopore
Michelle Akerman1, Liron Nuttman2, Maya Gofer2, Dvir Rotem1, Danny Porath1,
Oded Shoseyov2
1
Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
2
Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
Nanopores have been used as stochastic sensors for the detection of analytes that range from small molecules to
DNA, RNA, and proteins. Proteins in a planar lipid bilayer platform can be used as nanopores in order to study
and identify these biological analytes. In this approach, individual analyte molecules modulate the ionic current
flowing through a single nanopore. SP1 (stable protein 1) is a ring-shaped, highly stable homododecamer
protein, originally isolated from Aspen trees (P. euphratica). SP1 is stable under extreme conditions such as
high temperatures, detergents and organic solvents, and over a wide range of pH. SP1 has a relatively large pore
diameter (3-4 nm) which can be manipulated in order to specifically detect a variety of analytes (DNA, RNA,
Proteins). It was recently shown that SP1 can be embedded into lipid bilayers, thus creating a nanopore. The
protein can be modified in order to change the charge distribution on its surface to further increase its stability
in the lipid bilayer; this can be done via site directed mutagenesis and/or chemical modifications to increase
surface hydrophobicity.
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PA-104
Allosteric Conformational and Topology Changes in the E. Coli Membrane
Fusion CusB Dimer
Aviv Meir, Sharon Ruthstein
Department of Chemisty, Bar-Ilan University, Ramat-Gan, Israel
Bacterial cells have developed sophisticated systems to deal with the toxicity of metal ions. The E.coli
CusCFBA is a complex efflux system, located in the periplasm, involving four proteins: CusA, CusB, CusC,
and CusF which is responsible for transferring Cu(I) and Ag(I) ions. The CusA, CusB and CusC are connected
together in an oligomerization ratio of 3:6:3 CusA:CusB:CusC to form the CusCBA periplasm membrane
transporter. CusB is an adaptor protein which connects the two membrane proteins CusA (inner membrane) and
CusC (outer membrane). The CusF is a metallochaperone who transfers Cu(I) and Ag(I) to the CusCBA
transporter from the periplasm. The crystal structures of CusB, CusC, CusF, and CusBA complex have been
resolved, shedding some light on the efflux mechanism of this intriguing system. However, since CusB is an
adaptor protein, its role in operating this system is significant, and should be understood in detail. Here, we
utilize EPR spectroscopy to target the conformational changes of the full CusB protein upon binding Cu(I). We
reveal that CusB is a dimer in solution, where the orientation of one molecule with respect to the other molecule
is varies up on Cu(I) coordination, resulting in a more compact CusB structure. These structural and topology
changes upon Cu(I) binding probably play the role of a switch for opening the channel and transferring metal
ions from CusB to CusC and out of the cell.
105
PA-105
Design and Synthesis of Novel Targeted Chemical Chaperones as a Basis for
Amyotrophic Lateral Sclerosis (ALS) Treatment
Salome Azoulay-Ginsburg, Tamar Getter, Arie Gruzman
Chemistry, Bar-Ilan University, Ramat-Gan, Israel
Amyotrophic Lateral Sclerosis (ALS), is a fatal neurodegenerative disease characterized by the selective
degeneration of motor neurons in the brain and spinal cord, which leads to progressive paralysis and death.
ALS is mostly acquired spontaneously (sALS), with inherited disease accounting for only 10-15% of all cases
(fALS). Chemical chaperones, which include polyols, trimethyl N-oxide (TMAO), phenylbutyric acid (PBA),
and different amino acid derivatives, have been shown to reverse the mislocalization and aggregation of
proteins associated with many human diseases. However, using chemical chaperones as drugs is limited by the
very high active concentrations (mM range) required for their efficacy. We propose to overcome this obstacle
by coupling known chemical chaperones to organelle-targeted moieties, such as lysosomes, ER, Golgi, and
mitochondria, where aggregation takes place. Based on this observation, we hypothesize that refolding of
Superoxide Dismutase 1 (SOD1) misfolded proteins by chemical chaperones in lysosomes will allow lysosome
proteolytic enzymes and proteosome systems to cleave the refolded proteins and prevent SOD1 aggregates and
cell death.
In previous study in our research group, we have synthesized several ester- and amide- based TMAO chemical
chaperones. The leading compound, 3-((5-((4,6-dimethylpyridin-2-yl)methoxy)-5-oxopentanoyl)oxy)N,Ndimethyl propan-1-amine oxide, has displayed both neuronal and astrocyte-protective effects in vitro in a
micromolar concentration range, and in daily doses of 10 mg/kg has dramatically improved the neurological
functions and has delayed the body weight loss in ALS mice. In addition, the compound significantly increased
the survival rate of Drosophila flies. Now, we have synthesized a series of novel compounds using FDAapproved chemical chaperone: phenylbutyric acid (PBA) with different intracellular targeting moieties and
linkers. These new compounds might serve as drug candidates for ALS disease treatment.
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PA-106
Design of Novel Amynoglycoside Derivatives with Enhanced Suppression of
Diseases-Causing Nonosense Mutations
Valery Belakhov, Narayana Murthy Sabbavarapu, Michal Shavit, Yarden Degani,
Boris Smolkin, Timor Baasov
Schulich Faculty of Chemistry, The Edith and Joseph Fischer Enzyme Inhibitors Laboratory,
Technion - Israel Institute of Technology, Haifa, Israel
New pseudotrisaccharide derivatives of aminoglycosides (AG) that exploit additional interaction on the shallow
groove face of the decoding-site rRNA of eukaryotic ribosome were designed, synthesized and biologically
evaluated. Novel lead structures (6 and 7 with an additional 7′-OH), exhibiting enhanced specificity to
eukaryotic cytoplasmic ribosome, and superior nonsense mutation suppression activity than those of
gentamicin, were discovered. The comparative benefit of new leads was demonstrated in four different
nonsense DNA-constructs underling the genetic diseases cystic fibrosis, Usher syndrome, and Hurler syndrome.
The recently solved X-ray crystal structure of eukaryotic ribosome in complex with the aminoglycoside G418
provided, for the first time, a clear picture of differences between the prokaryotic and eukaryotic sites, which
was exploited here for the rational design of new compounds that selectively target the eukaryotic cytoplasmic
rRNA A-site. Using this tool, we discovered a new pharmacophore, 7-hydroxyl group, as a valuable structural
element of the glucosamine ring that significantly affects eukaryotic versus prokaryotic selectivity. In addition,
the observed data support the feasibility of using the rational design strategy employed here for the construction
of new AG derivatives that may act as a new drug for the treatment of various genetic disorders.
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PA-107
Hydrophosphoryl Derivatives of Tetraene Macrolide Antibiotic Tetramycin B:
Design, Synthesis, Antifungal Activity and Development of Intellectual
Computer System
Valery Belakhov1, Alexander V. Garabadzhiu2, Tamara B. Chistyakova3, Igor A. Smirnov3,
Eldar E. Musayev3, Sergey S. Kasimovskiy3
1
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
2
Laboratory of Molecular Pharmacology, Saint-Petersburg State Technological Institute
(Technical University), Saint-Petersburg, Russia
3
Department of Computer-Aided Design and Control Systems, Saint-Petersburg State
Technological Institute (Technical University), Saint-Petersburg, Russia
Antifungal antibiotic tetramycin B discovered by German researchers is a member of tetraene macrolide
antibiotics family. Tetramycin B was prepared via the microbiological synthesis by Streptomyces noursei as the
producer; its structure as well as physical, chemical, and medical and biological properties have been studied in
detail. However, in contrast to tetraene macrolide antibiotics nystatin and pimaricin, tetramycin B has not been
applied in the mycological therapy due to the high toxicity. Chemical modification of polyene macrolide
antibiotics is known to afford less toxic derivatives with improved chemotherapeutical properties and extended
range of biological activity.
We have demonstrated that reactions of tetraene macrolide antibiotic tetramycin B with aromatic aldehydes and
hypophosphoric acid lead to the formation of its hydrophosphoryl derivatives. The studied reaction can be
considered as a specific version of the Kabachnik-Fields reaction. In the first stage of the process, the primary
amino group of the mycosamine (3-amino-3,6-dideoxy-D-mannose) combines with the carbonyl group of the
aromatic aldehyde, with the formation of an azomethine intermediate. In the second stage hypophosphoric acid
reacts with the C=N bond of the azomethine intermediate, with the formation of hydrophosphoryl derivatives of
tetramycin B.
Biological studies showed that hydrophosphoryl derivatives of tetramycin B were less toxic than initial
antibiotic and have expressed antifungal activity against 11 test-cultures of yeast-like fungi of the genus
Candida.
Different types of information systems have been applied for efficient synthesis and production of the drugs to
be used in diseases diagnostics and treatment. The Intellectual Computer System for optimal choice of the
conditions for rational design, synthesis and using in medical practice of novel derivatives of polyene macrolide
antibiotics was developed.
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PA-108
Sweet Taste and Chirality – Interactions of Sugars and Amino Acids with the
Human Sweet Taste Receptor
Yaron Ben Shoshan-Galeczki, Masha Y. Niv
The Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of
Agriculture, Food and Environment & Fritz Haber Center for Molecular Dynamics,
The Hebrew University of Jerusalem, Rehovot, Israel
Sweet taste is one of the primary determinants of food preference and intake and has a huge impact on health
and global economy, leading to constant search for cost effective, healthy, novel sweeteners. Here we analyze
the molecular recognition of ligands by the sweet taste receptor, focusing on the role of chirality in the
sweetness of sugars and amino acids. The sweet taste receptor is comprised of Tas1R2 and Tas1R3 monomers.
Homology modeling of the extracellular Venus Fly Trap (VFT) domain of the receptors was based on the
metabotropic glutamate receptors (mGluR) Xray structures. Next, an automated docking campaign to screen the
models against their known ligands (and decoys with similar physicochemical properties but dissimilar 2D
topologies) was carried out. Analysis of over 20,000 compounds showed higher ranking of true positives
compared to decoys in 95% of the cases, implying high sensitivity and specificity of the models. Ligandreceptor interactions analysis was validated using existing data about sweet compounds. Interestingly, the
binding site was found to be semi-symmetrical around a hinge (Arg385). The predicted interactions are
compatible with high specificity for enantiomers of amino acids, along with lack of stereospecificity towards Land D-sugars. Our results successfully post-dicted recently patented sweeteners, providing an efficient protocol
for prospective prediction of novel sweeteners by in-vitro screening.
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PA-109
Combinations of Anticancer Ti(IV) Phenolato Complexes with Other
Anticancer Drugs: Toxicity and Cytotoxicity Measurements in vitro and in vivo
Nitzan Ganot1, Ori Braitbard2, Jacob Hochman2, Edit Y. Tshuva1
The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
2
Department of Cell and Developmental Biology, Alexander Silberman Institute of Life
Science, The Hebrew University of Jerusalem, Jerusalem, Israel
1
The significant drawbacks of cisplatin, namely its high toxicity and development of drug-resistance, initiated an
extensive search for other metals that can lead to anti-cancer activity. Ti(IV) complexes showed promising
cytotoxic activity, and two Ti(IV) based complexes reached clinical trials. Nevertheless, these complexes have
failed the trials due to instability in aqueous environment. Our group designed a new family of anti-cancer
Ti(IV) complexes based on phenolato ligands, which showed high cytotoxic activity toward numerous cancer
cell lines and enhanced stability in aqueous environment.
Combination therapy is very common in clinical treatment of cancer. By combining two drugs or more, the
doses required to reach the desired effect are reduced, and consequently, side effects, toxicity, and the risk of
developing drug resistance are reduced as well.
In earlier research, cytotoxicity measurements of the combinations of phenolato Ti(IV) complexes with other
organic and inorganic anticancer drugs were performed on different types of cancer cell lines. The
combinations showed mostly synergistic and additive behavior, which is medicinally valuable.1
Herein, specific combinations of phenolato Ti(IV) complexes with the drug commonly employed for a tested
cell line are presented. The cell lines that respond best to the Ti(IV) phenolato complexes were identified by the
NIH screening test. In vitro and in vivo anticancer measurements of the combination of the phenolato Ti(IV)
complex with the drug that is clinically used to treat the identified cancer type were performed. Achievements
in these directions will be discussed.
(1) Ganot, N.; Redko, B.; Gellerman, G.; Tshuva, E. Y. Rsc Adv. 2015, 5 (11), 7874–7879.
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PA-110
Evaluating the Peptide Structure Prediction Capabilities of a Purely Ab-Initio
Method
Moshe Goldstein1,3, Moshe Amitay2
Department of Computer Science, Jerusalem College of Technology, Jerusalem, Israel
2
Department of Bioinformatics, Jerusalem College of Technology, Jerusalem, Israel
3
The Fritz Haber Research Center, The Hebrew University of Jerusalem, Jerusalem, Israel
1
Peptides, such as hormones and antibiotics, play many biological functions. Peptides` tertiary structures are of
paramount importance for understanding their function, as well as the interactions with other molecules.
DEEPSAM[1] (Diffusion Equation Evolutionary Programming Simulated Annealing Method) is a novel purely
ab-initio global optimization algorithm aimed to predict the structure of peptides and proteins, from amino acid
sequence, without any preliminary assumption. This method is an Evolutionary Programming algorithm whose
mutation operators are built by hybridizing the advantages of three well-known optimization methods Diffusion Equation Method (DEM), Molecular Dynamics Simulated Annealing (MDSA), and the BFGS quasiNewton local minimization method.
In principle, DEEPSAM requires much less computing resources and is much faster than other structure
prediction methods, such as Replica Exchange Molecular Dynamics (REMD), and therefore seems to be more
suitable for industrial use.
The goal of this study has been to further evaluate the structure prediction accuracy of the DEEPSAM
algorithm by running it against a large number of known NMR structures of linear peptides (10-20 residues), in
an aqueous environment modeled by the GBSA implicit solvent model.
[1] M. Goldstein, E. Fredj, and R. B. Gerber: "A New Hybrid Algorithm for Finding the Lowest Minima of
Potential Surfaces: Approach and Applications to Peptides", J. of Computational Chemistry, vol. 32, pp 1785–
1800, (2011).
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PA-111
Novel CCAT1 and K-Ras Peptide Nucleic Acids with Specific Illumination at
the Far-Red Spectrum
1
Dina Hashoul1, Kolevzon Netanel1, Aviram Nissan2, Abraham Rubinstein1, Eylon Yavin1
The School of Pharmacy, Institute for Drug Research, The Hebrew University of Jerusalem,
Jerusalem, Israel
2
The Chaim Sheba Medical Center, Sheba General Hospital, Tel-Hashomer, Israel
In the past decades much effort has been put forth in the discovery of biomarkers in cancer as means for
designing novel drug targets and for diagnostic purposes. Using RNA as a biomarker has the advantage that
detection could, in principle, be based not only on the over-expression of a given RNA molecule in malignant
cells but also on the discrimination between mutated and non-mutated transcripts that are manifested in many
types of malignancies.
The long non-coding RNA transcript, colon cancer associated transcript-1 (CCAT1) is highly expressed in
human colorectal cancer with none or minimal expression in normal tissues [1]. Because CCAT1 is upregulated in the vast majority of precancerous polyps and lymph nodes it could serve as an efficient biomarker
for real time imaging and for screening purposes. In the context of early diagnosis mutated Kras oncogene was
explored in our group as well. We have previously shown that cytosolic mutant K-ras as well as CCAT1 could
be detected in living colon cancer cells by the forced intercalation (FIT) approach, using peptide nucleic acids
(PNAs) in which the intercalated dye, thiazole orange (TO), served as a fluorescent base surrogate [2]. Alas, the
specific emission spectra (ca. 530 nm) of TO is problematic for in vivo imaging due to the auto-fluorescence of
biological specimens, including cell lines.
In this study we report on novel fluorescent probes (at the far red region), where the surrogate base TO is
replaced by a novel fluorophore (BisQ) that emits light in the far-red region. The novel fluorophore is, in turn,
incorporated into PNA sequences capable of hybridizing with cytosolic mutant K-ras mRNA and CCAT1
sequences in relevant cancer cells. The design of the new PNA also includes a cell penetrating peptide (dK 4)
enabling the PNA to enter the cancer cells without the aid of a transfection agent.
BisQ labeled PNAs were shown to detect both biomarkers in living cancer cells as well as the CCAT-1
biomarker in mildly fixed human biopsies from patients with colorectal cancer.
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PA-112
Exploring Random Sequences Peptides for Antimicrobial Uses
Tal Stern, Zvi Hayouka
Institute of Biochemistry Food Science and Nutrition, The Hebrew University of Jerusalem,
Rehovot, Israel
Resistance to antibiotics is a serious worldwide crisis that possess the challenge of development new chemical
tools to tackle it. Random-sequence peptide mixtures (natural Antimicrobial peptides analogues) are composed
of a hydrophobic and cationic amino acids in binary ratio with controlled chain length and stereochemistry.
Although the sequences are random, high and efficient microbial growth inhibition achieved in low
concentrations. The influence of amino acids identity on the antimicrobial activity against varied bacteria has
explored. The random sequenced peptides mixtures have a rapid mode of action against the bacteria including
entry into the bacterial cells. The promising potential of use in medical and food aspects has studied by
exposure pathogens or food associated bacteria to the random sequenced peptide mixtures. These compounds
have great potential as new antimicrobial agents for several applications.
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PA-113
Orthogonal Deprotection of Cys Protecting Groups using Palladium(II)
Complexes for the Synthesis of Modified Peptides and Proteins
Shay Laps, Muhammad Jbara, Suman Kumar Maity, Ashraf Brik
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
Herein we report for the first time on our findings about orthogonal activities of Pd(II) complexes in the
synthesis of modified peptides and proteins. In addition to our previously reported uses of Pd(II) complexes in
the removal of various Cys protecting groups in highly efficient manner, 1-4 we found that Pd(II) can unmask
Cys(t-butyl) in peptides under aqueous conditions. With this in hand, we developed new conditions, which
enable orthogonal removal of highly useful Cys protecting groups, including thiazolidine (Thz),
acetamidomethyl (Acm) and t-butyl, assisted by Pd(II). We succeeded to remove the Thz with (AllylPdCl)2 in
aqueous buffer without affecting the Acm protecting group in the presence of glutathione (GSH) in equal molar
ratio to the Pd(II). However, with higher amounts of Pd(II) relative to GSH, the Acm deprotection proceeded
smoothly. Under these conditions t-butyl protecting group is stable and only using unique conditions with
Pd(II) we observed efficient removal of the t-butyl. These novel findings enabled us to explore the preparation
of a library of peptides bearing different modifications by selective deprotection and alkylation steps. Together,
this opens new opportunities in peptide and protein chemistry and chemical biology, which we are currently
exploring.
References:
1. Jbara, S. K. Maity, M .Seenaiah, A. Brik, J. Am. Chem. Soc. 2016, 138, 5069–5075.
2. K. Maity, M. Jbara, S. Laps, A. Brik, Angew. Chem. Int. Ed. 2016, 55,8108–8112.
3. K. Maity, G. Mann, M. Jbara, S. Laps, G. Kamnesky, A. Brik, Org. Lett. 2016, 18,3026–3029.
4. Jbara, S. Laps, S. K. Maity, A. Brik, Chem. Eur .J. 2016, 22,14851–14855.
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PA-114
Palladium Assisted Rapid Removal of a Solubilizing Tag from a Cys Side
Chain to Facilitate Peptide and Protein Synthesis
Guy Mann, Suman Kumar Maity, Muhammad Jbara, Shay Laps, Guy Kamnesky, Ashraf Brik
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
Reversible attachment of solubilizing tags to hydrophobic peptides that are resistant to cleavage condition and
yet removable from the final ligated product is an essential and challenging task in chemical protein synthesis
in order to facilitate multiple purification and ligation steps. Herein we report on the efficient palladiumassisted removal of solubilizing tag linked to the Cys side chain. The strategy was applied for the efficient
preparation of histone protein H4 from two fragments via one-pot operation of ligation, removal of solubilizing
tag and desulfurization
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PA-115
Synthesis and Evaluation of NPP1 Inhibitors as Potential Drugs for the
Treatment of Osteoarthritis/CPPD Disease
Molhm Nassir1, Shani Journo2, Abed Saady1, Uri Arad2, Bilha Fischer1
1
Department of Chemistry, Bar-Ilan University, Ramat-Gan, Israel
2
Department of Rheumatology, Tel Aviv Medical Center and the Faculty of Medicine, Tel Aviv,
Israel
Overproduction of extracellular pyrophosphate due to hydrolysis of ATP by NPP1 leads to deposition of
pathological Ca2P2O7·H2O (CPPD) in cartilage, resulting in a degenerative joint disease (CPPD disease) which
has no cure. We explored the hypothesis that NPP1 inhibitors may be therapeutic agents for CPPD disease by
inhibiting the hydrolysis of ATP. Specifically, we synthesized novel analogs of ADP (an NPP1 substrate) in
which the Pa,b bridging oxygen atom is replaced by a methylene group, and a derivative where both Pa,b
phosphate groups are replaced by sulfonate groups, 1. and the Pb phosphate is replaced by a sulfonate isoster, 2,
In addition, we synthesized an ADP analog in which the ribose ring was cleaved, and the primary alcohol was
substituted by bis-phosphonate, 3. To predict the ability of the derivatives to inhibit NPP1, we evaluated the
affinity and selectivity of the analogs to Zn2+ involved in NPP1’s catalytic activity. We titrated the analogs with
Zn2+- or Ca2+ ions and monitored the titrations by UV. Analogs 1 and 2 selectively coordinated Zn2+, and not
Ca2+, and formed ZnL2 complexes, whereas analog 3 showed no affinity for Zn2+ and Ca2+ ions. Next, analogs
1, 2, and 3 have been evaluated for their inhibitory effect on NPP1 in human chondrocytes. Analog 3 proved to
be a promising inhibitor reducing NPPase activity in human chondrocytes by 90% at 100 µM, vs. analogs 1,
and 2 (40% and 30% inhibition at 100 µM). Analogs 1, 2, and 3, were found to be NPP selective showing no
activity at TNAP. In summary, analog 3 was found to be an effective and selective NPP1 inhibitor in human
chondrocytes. Since analog 3 is a poor Zn2+-chelator, we hypothesize that its inhibitory effect may be related to
its high flexibility at NPP1’s catalytic site.
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PA-116
The Non-Aqueous Sol-Gel Mediated Microencapsulation of Deep Eutectic
Solvents: Characterization and Application
Charlie Batarseh, Raed Abu-Reziq
The Department of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
In last decade, deep eutectic solvents (DESs) have surfaced as promising alternatives to conventional solvents
in synthesis. DESs exhibit low volatilities, high thermal stabilities, impressive solubilization capacities for
various metal oxides and electrolytes and high biodegradability. In addition, they can be easily modified and
fine-tuned to serve specific objectives. On the other hand, DESs usually comprise high viscosities that limit
their applicability in catalysis, especially in large-scale industries.
The main objective of this research is to microencapsulate DESs via a non-aqueous sol-gel technique using
formic acid as both a reagent and a catalyst. Particularly, proline-based DESs, which may be used as catalysts
in various organic reactions such as Aldol, Michael and Mannich reactions. This technique eliminates most of
the drawbacks that originate from the high viscosity of DESs by turning them into easily handleable and
dispersible solids. Typically, DESs are encapsulated using oil in oil (O/O) emulsions as templates for the
interfacial polymerization between formic acid and suitable silanes. This produces porous silica shells that
surround the DESs droplets and separate them from the outer environment. The microencapsulated DESs may
then be used as catalysts in various organic reactions and as hosts for different enzymes, organocatalysts,
organometallic catalysts and drugs.
Several DESs were successfully encapsulated using the non-aqueous sol-gel technique. The capsules were
analyzed using SEM, TEM, solid NMR, IR and TGA techniques and then tested in catalysis. For example
Choline chloride: L-tartaric acid (1:0.5) DES was used for the one-pot synthesis of α-aminophosphonates.
Whereas, proline: formic acid (1:2) DES was employed in Aldol condensations and Michael additions. The
preparation and characterization of these microencapsulated DESs will be presented.
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PA-117
The Greenest Process: Amino Acids as New Heavy Metal Chelators for
Environmental Remediation
Noam Dolev1,2, Zhanna Katz1,2, Zvi Ludmer1, Amos Ullmann2, Neima Brauner2,
Roman Goikhman1
1
Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem,
Rehovot, Israel
2
Environmental Engineering, Tel Aviv University, Tel Aviv, Israel
Remediation of soils that are contaminated with toxic heavy metals is a global challenge. Powerful synthetic
chelating agents such as commonly used EDTA, are applied for extracting heavy metals from contaminated
soils. However, EDTA is not biodegradable, and interferes with environmental biochemical processes.
Therefore search for powerful biodegradable chelators is extensively studied worldwide.
In the present research, we explore natural amino acids as the most environmentally-friendly chelators for soil
remediation. Amino acids are well-known to chelate metal ions in nature, are non-toxic, inexpensive, and even
enhance plant growth. So far we present the first comprehensive study of exploring amino acids as potential
chelators for the environmental remediation processes.
Screening of various natural amino acids allowed us to find the best candidates for our goal, and to observe
structure-functional correlations between specific structural fragments (and properties), and metal extracting
efficiency. Also, idea of recovery and re-use of amino acids was examined.
Both the stunning advantages and the curious faults of amino acid application as chelators in soil remediation
will be discussed in the present poster.
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PA-118
Electron Exchange Columns for Contaminated Water Treatment
Neelam Singh1, Yael Albo2, Ariela Burg3, Dror Shamir4, Dan Meyerstein5
1
Chemical Sciences, Ariel University, Ariel, Israel
2
Chemical Engineering, Ariel University, Ariel, Israel
3
Chemical Engineering, Sami Shamoon College of Engineering, Beer-Sheva, Israel
4
Chemistry, Nuclear Research Center, Beer-Sheva, Israel
5
Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
Electron exchange columns are analogous to ion exchange columns. Recently it was shown that entrapment of a
strong redox species inside the sol-gel silica matrices yields good reducing electron exchange columns.1 The
electron exchange columns are more advantageous as the entrapped species do not contaminate the products
while performing the redox reactions. Such columns can be utilized for the treatment of polluted water.
Halogenated compounds and bromate (BrO3-) constitute a major problem to the environment because of their
carcinogenic nature and toxicity.2,3 The halogenated acetic acids and bromate are some of the main
contaminants which are widely distributed in the ground water and surface water therefore several approaches
have been made in the past for the decontamination/treatment of water through metal complexes. In the present
study electron exchange columns prepared through entrapment of polyoxometalates and zero-valent iron
species in silica matrices were shown to degrade these toxic compounds into non-toxic products in aqueous
solutions.
Reference:
1] Neelam, Y. Albo, D. Shamir, A. Burg, S. Palaniappan, G. Goobes, D. Meyerstein, Coord. Chem.,
2016, 69, 1.
2] Sattari, C. L. Hill, J. Am. Chem. Soc., 1993, 115, 4649.
3] Huang, NY Zao, PP. Lu, J. Environ. Sci., 2007, 28, 2264.
Acknowledgements: This study was supported in part by a grant from the Pazy foundation.
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PA-119
Perceived and Actual Knowledge of Pre-Service Chemistry Teachers in the
Energy Topic
Marina Tal1, Orit Herscovitz1, Yehudit Judy Dori1,2
1
Faculty of Education in Science and Technology,
Technion-Israel Institute of Technology, Haifa, Israel
2
Samuel Neaman Institute for Advanced Studies in Science and Technology, Technion-Israel
Institute of Technology, Haifa, Israel
The subject of chemical energy consists of abstract concepts and a variety of graphical data representation. Preservice chemistry teachers who are on the verge of starting to teach this complex subject might face challenges
while planning the teaching of this material. Consequently, it is important to expose the knowledge of the preservice teachers in chemical energy, to verify its level of understanding, and to develop the content knowledge
and pedagogical content knowledge of these teachers.
The research goal is to examine the perceived and actual knowledge of pre-service teachers in chemical energy.
Research objectives include:
-
Evaluating perceived knowledge of the pre-service chemistry teachers with respect to chemical
energy concepts.
-
Determining the characteristics of pre-service teachers’ chemical understanding with respect to
concepts chosen by them and questions they raised.
-
Analyzing the gap, if any, between the perceived and the actual knowledge of the pre-service
chemistry teachers in the concepts of chemical energy.
Research participants include a group of 25 pre-service chemistry teachers undertaking the course ‘Advance
Topics in Chemistry Teaching’.
In this research, a questionnaire is used to expose pre-service chemistry teachers perceived vs. actual
knowledge. Using a Lykert type questions (1-5 scale), we ask the pre-service teachers to indicate their
perceived knowledge level of chemistry by referring to several chemical-energy related concepts, before and
after studying the course, and to actually explain one of these concept. The pre-service teachers also posed
questions after reading a short text on this topic
Preliminary results will be presented and discussed. This research will provide recommendations for chemical
educators who teach prospective teachers to focus on the concepts which are more difficult to grasp and how to
analyze question complexity level.
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