Supporting Information
© Wiley-VCH 2006
69451 Weinheim, Germany
“Click” Chemistry by Microcontact Printing
D. I. Rożkiewicz, D. Jańczewski, W. Verboom, B. J. Ravoo,* and D. N. Reinhoudt*
Laboratory of Supramolecular Chemistry and Technology, MESA+ Institute for Nanotechnology,
University of Twente, P. O. Box 217, 7500 AE Enschede, The Netherlands. E-mail: [email protected]
1. Synthesis of Lissamine Rhodamine Modified with Acetylene Unit (LRA)
The synthesis of the acetylene-modified lissamine rhodamine (LRA) was performed in
three steps as outlined below:
O
NH2NH2
KPht
Cl
N
1
2
O
N
Lissamine rhodamine
sulfonyl chloride
NH2
EtOH b.p.
70°C
+
N
O
Et3N
S
O
O
S
NH
O
O
O
3
6-Phthalimido-1-hexyne (1). Potassium phthalimide (12.428 g, 67 mmol) was added
to a solution of 6-chloro-1-hexyne (5 mL, 41 mmol) in 100 mL of DMF. After stirring
for 16 h at 70 °C the solvent was evaporated and the solid residue was suspended in
CH2Cl2 and filtered through layer of silica gel 60. Evaporation of solvent gave the
desired product (7.90 g, 35 mmol, 85 %). 1H NMR (300 MHz, CDCl3): δ = 7.85 – 7.83,
7.72 – 7.69 (m, 4 H, Ph), 3.72 (t, 2 H, J = 6.9 Hz, CH2N), 2.57 (m, 2 H, CH2CH2CCH),
1
1.93 (t, 1 H, J = 2.7 Hz, CH2CH2CCH), 1.85 – 1.78, 1.61 – 1.50 (m, 4 H, CH2).
13
C
NMR (CDCl3, 75MHz): δ = 168.6 (CO), 131.1, 132.3, 123.4 (Ph), 83.9, 69.0
(CH2CCH), 37.6, 27.9, 25.8, 18.2 (CH2); FAB MS measured 228.1, calculated for
[C14H13N + H]+ 228.1.
6-Amino-1-hexyne (2). Hydrazine hydrate (2 mL, 42 mmol) was added to a solution of
6-phthalimido-1-hexyne (1) (2.79 g, 12 mmol) in ethanol. The mixture was stirred in
reflux for 1h, then cooled to room temperature and filtered. Evaporation of the solvent
yielded the desired product (0.53 g, 5.4 mmol, 45 %). 1H NMR (CDCl3, 300MHz) δ =
2.78 (t, 2 H, J = 6 Hz, CH2NH2), 2.62 (br, 2 H, NH2), 2.57 (m, 2 H, CH2CH2CCH), 1.95
(t, 1 H, J = 2.4 Hz, CH2CH2CCH), 1.64 – 1.55 (m, 4 H, CH2);
13
C NMR (CDCl3,
75MHz) δ = 84.5, 68.6 (CH2CCH), 41.8, 32.7, 26.0, 18.5 (CH2); FAB MS measured
98.1, calculated for [C6H11N + H]+ 98.1.
Lissamine rhodamine B sulfonyl acetylene amide (LRA, 3). 6-amino-1-hexyne (2)
(0.198 g, 2.67 mmol) was added to a solution of lissamine rhodamine B sulfonyl
chloride (mixture of isomers), (0.295 g, 0.34 mmol) in 40 mL of dry THF.
Subsequently 0.1 mL of triethylamine was added and the mixture was stirred at room
temperature for 3 h and then left at -20 °C for 16 h. After addition of 3 mL of 1 M
NaOH and 20 ml of EtOH, the mixture was filtrated and the solvent was evaporated
resulting in the expected product (0.161 g, 0.252 mmol, 74 %). The product (composed
of a mixture of isomers) was used without further purification. FAB HRMS measured
660.21416, calculated for [C33H39N3O6S2 + Na]+ 660.21780.
2
2. Scavenging of metal ion contaminants
To exclude that any trace residues of metals ions could influence the rate of the triazole
formation, the reaction between azide-terminated SAM and acetylenes was performed
in the presence of the metal-complexing agent (0.05 mM EDTA).
Grazing-Angle Infrared Spectroscopy
The azide-terminated monolayer was formed as previously described and showed the
absorption at 2089 cm-1 (νas (N3)) (Figure S-1, 1). When the azide-terminated SAM was
reacted for 48 h with 1-octadecyne in ethanol solution with 0.05mM EDTA (Figure S1, 2) the azide peak disappeared and in addition two bands responsible for methyl
stretching were visible. The band at 2960 cm-1 is the asymmetric in-plane C-H
stretching mode (νas (CH3)) and the band at 2871 cm-1 is the symmetric C-H stretching
mode of the CH3 group (νs (CH3)). The bands at 2935 cm-1 and 2855 cm-1 are the
asymmetric and symmetric C-H stretching modes of the CH2 group. After μCP of
octadecyne (5mM ethanolic solution with 0.05mM EDTA) via a flat PDMS stamp for
15 min (Figure 1, 2*) the IR spectrum was nearly identical for the reaction conducted
from solution. Grazing-angle infrared spectroscopy revealed no changes in the spectra
in comparison with the monolayers formed without the presence of EDTA (Figure S-1).
Figure S-1. Grazing-angle infrared spectra of the “click” reaction performed in the
presence of EDTA. 1-azide-terminated SAM, 2- azide-terminated SAM reacted with 1octadecyne from an ethanol solution with 0.05 mM EDTA, 2*- azide-terminated SAM
reacted with 1-octadecyne (with 0.05 mM EDTA present) via μCP.
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Confocal Fluorescence Microscopy
Lissamine rhodamine modified with acetylene unit (LRA), was used as an ink (1 mM
ethanolic solution with 0.05 mM EDTA) to print patterns onto azide-terminated glass
slide. The PDMS stamp was oxidized with UV/ozone plasma for 30 min in order to
change surface wettability into more hydrophilic one. Directly after oxidation the stamp
was inked with 1 mM ethanolic solution of LRA, dried with nitrogen for 1 min and
brought into conformal contact with an azide-terminated SAM on a glass slide for 1
min contact time. The substrate was vigorously rinsed with MilliQ water and sonicated
in ethanol for 5 min and dried with nitrogen (Figure S-2A). To exclude physisorption
(or any other form of non-specific adsorption) of ink LRA the same ink was printed
onto a glass slide modified with n-dodecyltriethoxysilane. The oxidized stamp was
inked with LRA (1 mM solution in ethanol) for 1 min and brought into conformal
contact with the glass substrate for 1 min. Subsequently the substrate was rinsed with
ethanol and sonicated in ethanol for 5 min. No significant absorption of LRA was
observed (Figure S-2B).
B
A
Figure S-2. Lissamine rhodamine-acetylene LRA printed on (A) an azide SAM in the
presence of EDTA and (B) a n-dodecyltriethoxysilane SAM. Images obtained after
rinsing and sonication.
4
X-Ray Photoelectron Spectroscopy
The surface of PDMS stamp was examined for metal contaminants that could influence
the rate of the triazole formation. No metals were detected by XPS on the surface of the
PDMS stamp.
Figure S-3. XPS survey scan of the PDMS stamp surface. Typical binding energies for
Cu are indicated. No Cu peaks are observed.
5