SUPPORTING INFORMATION

Transcription

1 SUPPORTING INFORMATION Fullerene Attached Polymeric Homogeneous/Heterogeneous Photoactivators for Visible Light-Induced CuAAC Click Reactions Omer Suat Taskin 1, Gorkem Yilmaz 1, Yusuf Yagci 1,2* 1 Department of Chemistry, Istanbul Technical University, 34469, Maslak, Istanbul, Turkey 2 Center of Excellence for Advanced Materials Research (CEAMR) and Department of Chemistry, Faculty of Science, King Abdulaziz University, 21589, Jeddah, Saudi Arabia Y. Yagci: yusuf@itu.edu.tr

2 Experimental Materials Fullerene (C 60, Sigma-Aldrich, 99%), benzyl bromide (Aldrich, 98%), phenylacetylene (Aldrich, 98%) ethyl 2-bromopropionate (Aldrich, 99%), 9-(chloromethyl) anthracene (Aldrich, 98%), 1-bromooctane (Aldrich, 99%), 4-nitro aniline (Aldrich, 99%), dimethyl sulfoxide (DMSO, Aldrich, 99%), triethyl amine (98%, Aldrich), dichloromethane (DCM, 99%, Aldrich), ethylene glycol dimethacrylate (EGDMA, Aldrich, 98%), 2,2-Dimethoxy-2- phenylacetophenone (DMPA, Aldrich, 99%), 2-Hydroxyethyl methacrylate (HEMA, Aldrich, 97%), chloroform (99%, Merck), toluene-4-sulfonyl chloride (98%, Aldrich), dimethyl formamide (DMF, 98%, Alfa Aesar), N,N,N,N,N -Pentamethyldiethylenetriamine (PMDETA, Aldrich), acetonitrile (MeCN, Aldrich, 99%), propargyl acrylate (Aldrich, 98%), propargyl alcohol (Aldrich, 99%), sodium azide (NaN 3, Panreac, 99%), and copper(ii) bromide (Cu II Br 2, Acros Organics, 99%) were used as received without any further purification. All solvents were purchased from Merck and used as received. Sodium nitrite (NaNO 2, Carlo Erba), magnesium sulfate (MgSO 4, Alfa Aesar, 99.5%), sodium bicarbonate (NaHCO 3, Aldrich, 99.7%), %), and SiO 2 particles in water (Ludox HS-40, Aldrich, 40 wt% suspension in H 2 O) were used as received. Instrumentation 1 H NMR spectra were recorded in CDCl 3 with Si(CH 3 ) 4 as an internal standard at 500 MHz on a Agilent VNMRS 500 spectrometer at room temperature (125 MHz for 13 C NMR). Fourier transform infrared (FTIR) spectra were recorded on PerkinElmer FTIR Spectrum One spectrometer with an ATR accessory (ZnSe, PikeMiracle accessory) and cadmium telluride (MCT) detector. Viscotek GPCmax Autosampler system, consisting of a pump, three Viscogel GPC columns (G2000HHR, G3000HHR and G4000HHR), a Viscotek differential refractive index (RI) detector with a THF flow rate of 1.0 ml min 1 at 30 C. The detector was calibrated with PS standards having narrow molecular weight distribution. Data were analyzed using Viscotek OmniSEC Omni-01 software. Synthesis of ω-azido Terminated Polystyrene Copper bromide (24.8 mg, 0.17 mmol), styrene (2 ml, 17 mmol), PMDETA (59.96 mg, 0.35 mmol) and ethyl 2-bromopropionate (31.3 mg, 0.17 mmol) were added to a Schlenk tube, which was then sealed and degassed by three freeze-pump-thaw cycles. The mixture was heated and stirred at 110 C in an oil bath. After 3 h, the polymerization was ceased by

3 opening the flask and exposing the catalyst to air. The final mixture was diluted in THF and passed through a short neutral alumina column in order to remove copper catalyst. The mixture was concentrated by rotary evaporation and subsequently precipitated in methanol. The precipitated polystyrene was filtered and dried under vacuum. The obtained bromine endfunctional polystyrene (2000 g mol -1, 0.17 mmol), sodium azide (0.17 mmol) and 3 ml of DMF were added in a flask. The clear homogeneous solution was stirred at room temperature for 24 h. Then, polystyrene was precipitated in methanol, filtered and dried in vacuum (M n, NMR (PS-N 3 ) = 2110 gmol -1, M n, GPC (PS-N 3 ) = 2300 gmol -1, Mw/Mn = 1.1). Synthesis of ω-azido Functionalized Poly(ethylene glycol) The synthesis of azide functionalized poly(ethylene glycol) (PEG-N 3 ) was performed as follows. Me-PEG (M n = 2000 g/mol) was dissolved in 10 ml chloroform under a nitrogen atmosphere and cooled in an ice bath (0 C) and pyridine (7.5 mmol) was added. Then, toluene-4-sulfonyl chloride (5.3 mmol) dissolved in 10 ml of chloroform was slowly added to the cold reaction flask. The reaction mixture was stirred overnight at room temperature. The solvent was removed under vacuum and the viscous liquid tosylate obtained was used in the azidation reaction without any purification. Sodium azide (3.3 mmol) was added to a solution of the obtained tosylate (1.08 mmol) in DMF and the reaction mixture was stirred for 2 days at 65 C. After extraction of the crude product with CH 2 Cl 2 /water, the organic layer was was concentrated and precipitated in to diethyl ether to give PEG-N 3. Synthesis of ω-alkyne Functionalized Poly(ethylene glycol) (PEG-Alkyne) Me-PEG (M n = 2000 g/mol) (1 eq) was dissolved in 25 ml of CH 2 Cl 2. 4-Pentynoic acid (3 eq), 4-dimethylaminopyridine (3 eq) and N, N'-dicyclohexylcarbodiimide (3 eq) in 5 ml of dichloromethane were added to the solution in that order. The reaction mixture was stirred overnight at room temperature. It was filtered and evaporated, and the remaining product was purified by column chromatography over silica gel eluting first with CH 2 Cl 2 /ethylacetate (1:1), and then with methanol/ch 2 Cl 2 (1:10). Finally, the organic phase was concentrated and precipitated in to diethyl ether to give PEG-Alkyne. Synthesis of ω-fullerene Terminated Polystyrene (PS-C 60 ) PS-C 60 was synthesized according to a previously reported procedure (M n, GPC (PS-C 60 )= 3000 gmol -1, M w /M n = 1.15)). 1

4 Synthesis of Azide Functional 2-Hydroxyethyl methacrylate (HEMA-N 3 ) 2-Hydroxyethyl methacrylate (HEMA, 5 ml, 0.16 mol) was dissolved in DCM under a nitrogen atmosphere and triethylamine (11.6 ml, 0.32 mol) was added. Then, toluene-4- sulfonyl chloride (23.4 g, 0.49 mmol) dissolved in DCM. The reaction mixture was refluxed overnight at boiling temperature of DCM. The solvent was removed under vacuum and the viscous liquid tosylate obtained was used in the azidation reaction without any purification. Sodium azide (0.502 g, 3.1 mmol) was added to a solution of the obtained tosylate (0.400 g, 1.04 mmol) in DMF and the reaction mixture was stirred for 2 days at room temperature. After extraction of the crude product with DCM/water, the organic layer was dried with anhydrous MgSO 4 and solvent was evaporated with a rotary evaporator. The resultant product was purified by a short flash column chromatography and restored in the fridge due to the explosive nature of the product. Synthesis of Azide Terminated Gel (HEMA-Gel) Gels were synthesized through light-induced free radical polymerization. A typical procedure for the preparation of the gels is as follows. EGDMA (1.24 ml, mol), HEMA (2 ml, mol), HEMA-N 3 (2 ml, mol) and DMPA (168 mg, mol) was dissolved in DCM and purged with nitrogen gas for 4-5 min and transferred into a special teflon material. After 45 min irradiation from a simple photoreactor equipped with two lamps (Philips TL-D 18 W) emitting light nominally at 350 nm at room temperature resulted in the formation of the desired gel. After polymerization, the formed gel was kept in THF at room temperature for at least 2 days for the removal of unreacted reagents to give azide functional gel. Synthesis of Fullerene Functional Gel (Gel-C 60 ) In a bottom flask, obtained azide functional gel (41% w/w HEMA-N 3, 150 mg) and fullerene (C 60, 867 mg) were mixed in toluene and refluxed overnight at boiling temperature to form fullerene terminated gel (Gel-C 60 ). The obtained Gel-C 60 have been washed several times with various solvents in order to remove any non-attached and free C 60, entrapped in the crosslinked structure. According to the TGA analysis, less than 10% mass of the gel is fullerene moiety. The gel was observed to swell only to a limited extent as a result of the high crosslinking density.

5 General Procedures for the Preparation of Azide Components 2, 3 To a solution of the corresponding bromide (benzyl bromide, ethyl 2-bromopropionate, and 9- (bromomethyl)anthracene) compounds (15 mmol, 1.0 eq) in 200 ml of DMSO was added sodium azide in excess (1.5 eq). The solution was stirred for at least 2 h at room temperature. Water (200 ml) was added to the mixture and after cooling down to room temperature, the aqueous solution was extracted with diethyl ether (3 100 ml). The organic layers were merged and washed with water (2 100 ml) and brine (100 ml). After drying over MgSO 4, the ether was removed under reduced pressure to yield azides. The corresponding aniline derivative (15 mmol, 1 eq.) was added to 80 ml of hydrochloric acid (17%) at room temperature followed by drop wise addition of ethanol to obtain a clear solution. The solution was cooled to 0 C and NaNO 2 (1.5 eq.) was added in small portions. After stirring at 0 C for 30 minutes, NaN 3 (1.5 eq.) was slowly added and the mixture was stirred for further 2 h at room temperature. The reaction mixture was extracted with diethyl ether (3 100 ml) and the combined organic fractions were washed with saturated NaHCO 3 solution (3 50 ml) and with brine (50 ml). After drying over MgSO 4, the ether was removed under reduced pressure to obtain azide. General Procedure for the Photoinduced CuAAC In a typical experiment NMR tube was filled with azide compound (1 mmol, 1 eq.), alkyne compound (1 mmol, 1 eq.), CuCl 2 (0.3 mmol), PMDETA (3 eq.), PS-C 60 (10 mg) or Gel-C 60 (30 mg) and DMSO (1 ml). The reaction was irradiated at room temperature by a Ker-Vis blue photo-reactor equipped with six lamps (Philips TL-D 18 W) emitting light nominally at nm (light intensity 45 mw.cm 2 ). After the reaction, Gel-C 60 was filtered and the resultant product was purified by a short column chromatography using ethylacetate:dichloromethane (30:70, v:v) as solvent. Synthesis of Telechelic Polymers by Photo-induced CuAAC Using Gel-C 60 Mono phenyl functional telechelics of poly(ethylene glycol) and polystyrenes were synthesized following a general procedure. Typical procedure for the preparation of monotelechelic is as follows: PS-N 3 (1 mmol, 1 eq.), PEG-N 3 (1 mmol, 1 eq.), phenylacetylene (1 mmol, 1 eq.), CuCl 2 (0.3 mmol), PMDETA (3 eq.) and PS-C 60 (10 mg) or Gel-C 60 (30 mg) were added to 2 ml DMSO. The reaction tube was irradiated by using the Ker-Vis blue photoreactor during 4 h. The mixture was diluted with CH 2 Cl 2. Then, the copper complex was removed out by passing through a neutral alumina column, and CH 2 Cl 2 was

6 removed by rotary evaporation. The mixture was precipitated in cold methanol, and the solid was collected after filtration and dried at room temperature under vacuum overnight. Synthesis of polystyrene-b-poly(ethylene glycol) by Photo-induced CuAAC Using Gel- C 60 To a Schlenk tube equipped with a magnetic stirrer, PS-N 3 (0.15 mmol, 1 eq.), PEG-alkyne (3 eq.), CuCl 2 (3 eq.), PMDETA (3 eq.) and Gel-C 60 (30 mg) were added to 2 ml DMSO. The tube was degassed by three freeze pump thaw cycles. The reaction tube was irradiated by using the Ker-Vis blue photoreactor. At the end of 24 h, the mixture was diluted with CH 2 Cl 2. Then, the copper complex was removed out by passing through a neutral alumina column, and CH 2 Cl 2 was removed by rotary evaporation. The mixture was precipitated in cold methanol, and the solid was collected after filtration and dried at room temperature under vacuum overnight. (M n,nmr : 6980 g mol 1, M n,gpc : 4900 g mol 1, M w /M n : 1.28). Benzyl azide. Yellow oil. Yield 96%. 1 H NMR (500 MHz, CDCl 3 ): δ (m, 5H), 4.36 (s, 1H). 13 C NMR (125 MHz, CDCl 3 ): δ 135.4, 128.8, 128.3, 128.2, Ethyl 2-azidopropanoate. Colorless oil. Yield 97%. 1 H NMR (500 MHz, CDCl 3 ): δ 4.24 (q, 2H), 3.91 (q, 1H), 1.46 (d, 3H), 1.30 (t, 3H). 13 C NMR (125 MHz, CDCl 3 ): δ 170.9, 128.3, 61.7, 57.3, 16.7, (Azidomethyl)anthracene

7 Yellow solid. Yield 95%. 1 H NMR (500 MHz, CDCl 3 ): δ 8.52 (s, 1H), 8.31 (d, 2H), 8.07 (d, 2H), (m, 2H), (m, 2H), 5.35 (s, 2H). 13 C NMR (125 MHz, CDCl 3 ): δ 131.4, 130.7, 129.3, 128.7, 129.0, 126.8, 125.8, 125.2, 123.5, Azidooctane Pale yellow oil. Yield 93%. 1 H NMR (500 MHz, CDCl 3 ): δ 3.26 (t, 2 H), (m, 12H), 0.89 (t, 3H); 13 C NMR (125 MHz, CDCl 3 ): δ 51.5, 31.7, 29.1, 28.8, 26.7, 22.6, 15.2, Azido-4-nitrobenzene Orange solid. Yield 87%. 1 H NMR (500 MHz, CDCl 3 ): δ (m, 2H), (m, 2H); 13 C NMR (125 MHz, CDCl 3 ): δ 146.8, 144.6, 125.6, PS-N 3 Yield 95%. 1 H NMR (500 MHz, CDCl 3 ): δ 7.32 (s, 1H), 7.28 (s, 1H), 7.21 (s, 1H), 7.19 (s, 1H), (m, 4H), 1,83 (t, 2H), (m, 2H), 0.76 (t, 3H). PEG-N 3 Yield 95%. 1 H NMR (500 MHz, CDCl 3 ): δ 3.55 (t, 2H), 3.52 (t, 2H) 3.40 (s, 3H), 1.68 (t, 2H).

8 Scheme S1. Synthesis of polystyrene derivative of fullerene (PS-C 60 ) Figure S1. GPC traces of the PS-N 3, and PS-C 60. Figure S2. Visible absorption spectra of C 60 and PS-C 60.

9 Figure S3. FT-IR spectra of the HEMA and HEMA-N 3 Figure S4. UV-Visible absorption spectra of HEMA-Gel and Gel-C 60.

10 Figure S5. UV-Fluorescence absorption spectra of HEMA-Gel and Gel-C 60. Figure S6. Reusability of the heterogeneous Gel-C 60 catalyst in CuAAC click reaction between benzyl azide and phenylacetylene.

11 Spectra of the click products given in Table 1 of the main text. #Run1 #Run2

12 #Run3 #Run4

13 #Run5

14 Spectra of the click products given in Table 2 of the main text. #Run1 #Run2

15 #Run3 Identical with spectrum of [#Run4] given in Table 1. #Run4 Identical with spectrum of [#Run5] given in Table 1.

16 References (1) Hawker, C. J. Macromolecules 1994, 27, (2) Alvarez, S. G.; Alvarez, M. T. Synthesis-Stuttgart 1997, 413. (3) Meudtner, R. M.; Ostermeier, M.; Goddard, R.; Limberg, C.; Hecht, S. Chem. Eur. J. 2007, 13, 9834.