Photocontrolled RAFT Polymerization Mediated by a

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1 Supporting Information Photocontrolled RAFT Polymerization Mediated by a Supramolecular Catalyst Liangliang Shen, Qunzan Lu, Anqi Zhu, Xiaoqing Lv, and Zesheng An* Institute of Nanochemistry and Nanobiology, College of Environmental and Chemical Engineering, Shanghai University, Shanghai , China Materials 5, 10, 15, 20-Tetra(4-pyridyl)porphyrin (TPP) and 2-(bromomethyl)naphthalene were purchased from J&K and used without further purifications. Cucurbit[7]uril (CB[7], 99%) was purchased from Shandong Shanda Colloidal Materials Co., Ltd, China. Meso-tetra(4-sulfonatophenyl) porphyrin (TPPS), N,N-dimethylacrylamide (DMA, 98%) and diacetone acrylamide (DAAM, 99%) were purchased from Fluka. 2-Hydroxylethyl acrylate (HEA, 97%), poly(ethylene glycol) methyl ether acrylate (PEGA, M n = 480 g/mol), and poly (ethylene glycol) methyl ether methacrylate (PEGMA, M n = 475 g/mol) were purchased from Sigma-Aldrich. The inhibitor contained in all monomers was removed by passing through an Al 2 O 3 column prior to use. 4-Cyano-4-(ethanesulfanylthiocarbonyl) sulfanylpentanoic acid (ETTC) was prepared according to ref 1. Meso-tetra(4-naphthalylmethylpyridyl) porphyrin (TPOR) was synthesized as reported in ref 2. Zn(II) meso-tetra(4-naphthalylmethylpyridyl) porphyrin (ZnTPOR) and Zn(II) meso-tetra(4-sulfonatophenyl) porphyrin (ZnTPPS) were synthesized according to ref 3. All PET-RAFT syntheses conducted in 20 ml glass tubes were degassed with nitrogen beforehand for at least 30 minutes and then exposed to green LED light (8 w, 520 nm) at a stirring of 500 rpm and 20 o C. After a certain time of reaction, the irradiation was switched off and the resulted mixture was subjected to air. Monomer conversion was analyzed by 1 H NMR spectroscopy; the number-average molecular weights (M n ) and polydispersities (M w /M n ) was measured by gel permeation chromatography (GPC). Characterization UV-vis absorption spectra were acquired on a Hitachi U-3010 UV-vis photospectrometer. Fluorescence spectra were recorded on a Hitachi U-3010 spectrophotometer. 1 H NMR spectroscopy was conducted on a Bruker AV 500 MHz spectrometer, with chemical shifts reported in ppm using solvent residue as the reference. GPC measurements were performed on a Waters Alliance e2695 GPC system, equipped with a Styragel guard column, Waters Styragel HR3, HR4, and HR5 columns (molecular weight range g/mol), and a 2414 refractive index detector. DMF (HPLC grade, containing 1 mg/ml LiBr) was used as the eluent at a flow rate of 0.8 ml/min. GPC samples were prepared by dissolving dry polymer powder in DMF (3-5 mg/ml) and filtered through a 0.20 μm Millipore filter. The temperature of the columns and detector was set at 65 o C and 45 o C, respectively. Analysis of molecular weight and dispersity was carried out using Empower 2 software against PMMA standards (molecular weight range g/mol). Dynamic light scattering (DLS) measurements were performed using a Malvern ZS90 with a He Ne laser (633 nm, 4 mw) at a 90 angle. Autocorrelation functions were analyzed by the cumulants S1

2 method to calculate the z-average (hydrodynamic) diameter and polydispersity index (PDI). TEM images of nanoparticles were obtained from a Jeol 200CX microscope (200 kv). To prepare the TEM samples, a small drop of the sample solution with an appropriate concentration was carefully deposited onto a carbon-coated copper electron microscopy (EM) grid and dried overnight at 40 o C and under vacuum condition. Synthesis of Homopolymer via CB[7]@ZnTPOR-catalyzed PET-RAFT Solution Polymerization CB[7]@ZnTPOR-catalyzed PET-RAFT polymerization in homogeneous solutions was conducted via the following general procedure. In most cases, the molar ratio of [M]:[ETTC]:[ZnTPOR]:[CB[7]] was maintained at 200:1:0.01:0.03, unless otherwise stated. The required amount of monomer, ETTC and CB[7]@ZnTPOR complex were introduced into a glass tube (20 ml) and degassed with nitrogen beforehand for at least 30 minutes. Then the glass tube was exposed to green LED light (8 w, 520 nm) at a stirring of 500 rpm and 20 o C. The distance of the glass tube to light bulb was 2 cm. After a certain time of polymerization, the irradiation was switched off and the resulted mixture was subjected to air. For the study of polymerization kinetics, aliquots of reaction samples were withdrawn at predetermined time intervals and used for 1 H NMR and GPC measurements. For example, a reaction stock solution consisting of DMA (0.5 g, 5.04 mmol), ETTC (6.63 mg, µmol) and CB[7]@ZnTPOR (1.5 ml of CB[7]@ZnTPOR stock solution, [ZnTPOR] = 168 μm, [CB[7]] = 504 μm) was introduced into a glass tube and degassed with nitrogen for 30 minutes. Then, the glass tube was irradiated in green LED light at a stirring of 500 rpm and 20 o C. After 4 h of polymerization, the LED light was turned off and the mixture was directly used for 1 H NMR to determine the monomer conversion. Before GPC measurement, the sample was dried for 12 h at 70 o C. Synthesis of Homopolymer via CB[7]@ZnTPOR-catalyzed PET-RAFT Solution Polymerization in the Presence of Oxygen A reaction stock solution consisting of DMA (0.5 g, 5.04 mmol), ETTC (6.63 mg, µmol) and CB[7]@ZnTPOR (1.5 ml of CB[7]@ZnTPOR stock solution, [ZnTPOR] = 168 μm, [CB[7]] = 504 μm) was introduced into a glass tube and the tube was sealed without oxygen removal. Then, the glass tube was irradiated with green LED light at a stirring of 500 rpm and 20 o C without nitrogen protection. After 20 h of polymerization, the LED light was turned off and the mixture was directly used for 1 H NMR and GPC measurements. Synthesis of Block Polymer via CB[7]@ZnTPOR-catalyzed PET-RAFT Solution Polymerization Two protocols were used to synthesize block polymers. For sequential RAFT polymerization, the molar ratio of [M]:[ETTC]:[ZnTPOR]:[CB[7]] maintained at 200:1:0.01:0.03 in most cases. The first block was synthesized via the procedure described for homopolymer synthesis. The synthesis of the second block was carried out under green LED light (8 w, 520 nm) at a stirring of 500 rpm and 20 o C without intermediate purification and extra-addition of ZnTPOR. The third block was synthesized in a similar procedure as the second block. For chain-extension of an isolated polymer with intermediate purification, the molar ratio of [M]:[ETTC]:[ZnTPOR]:[CB[7]] also maintained at 200:1:0.01:0.03 in most cases. The first block was synthesized via the procedure described for homopolymer synthesis. Before chain-extension, the first block was purified through dialysis against water and freeze-drying. For example, a reaction stock solution consisting of DMA (0.5 g, 5.04 mmol), ETTC (6.63 mg, µmol) and S2

3 (1.5 ml of stock solution, [ZnTPOR] = 168 μm, [CB[7]] = 504 μm) was introduced into a glass tube and degassed with nitrogen for 30 minutes. Then, the glass tube was irradiated in green LED light at a stirring of 500 rpm and 20 o C. After 5 h of polymerization, the monomer conversion was confirmed to 95% 1 H NMR. Then, HEA (0.57 g, 5.04 mmol) was added and degassed for at least 30 minutes. The reaction mixture was irradiated in green LED light at a stirring of 500 rpm and 20 o C. After 2 h of polymerization, the monomer conversion of HEA was confirmed to 40% by 1 H NMR. Synthesis of PDMA Multiblock Homopolymers via Successive Chain Extensions Mediated by CB[7]@ZnTPOR-catalyzed PET-RAFT Solution Polymerization First, a PDMA homopolymer targeting a DP of 100 was synthesized under nitrogen atmosphere with a mononer conversion was 96%. For the second block, DMA in an aqueous solution was carefully added and the reaction mixture was then degassed with nitrogen before polymerization under green light irradiation. It is worth noting that there was no extra addition of the catalyst. The target DP for the second block was 100 and the monomer conversion was 95%. The third to eighth blocks were synthesized following the same protocol. The details of polymerization conditions and results were summarized in Table S5. Dispersion Polymerization via CB[7]@ZnTPOR-catalyzed PET-RAFT Polymerization PDMA 36 was first synthesized by thermally initiated RAFT polymerization targeting a DP of 50 and 72% conversion was reached in 2 h. Then PDMA 36 was purified via dialysis and freeze-drying. For CB[7]@ZnTPOR-catalyzed RAFT dispersion polymerization of DAAM, the molar ratio of [PDMA 36 ]:[[CB7]]:[ZnTPOR] was maintained at 1:0.03:0.01. The reaction mixture was degassed for 30 min and irradiated in green LED light (8 w, 520 nm) at a stirring of 500 rpm and 20 o C. After a certain time of polymerization, the irradiation was switched off and the mixture was subjected to air. For example, a reaction stock solution consisting of DAAM (0.43 g, 2.52 mmol), PDMA 36 (47.5 mg, µmol) and CB[7]@ZnTPOR (1.36 ml of CB[7]@ZnTPOR stock solution, [ZnTPOR] = 185 μm, [CB[7]] = 555 μm) were introduced into a glass tube. The reaction mixture was degassed for 30 min and irradiated in green LED light (8 w, 520 nm) at a stirring of 500 rpm and 20 o C. After 4 h of polymerization, the irradiation was switched off and the resulted mixture was subjected to air. The mixture was used for DLS and TEM analysis. Kinetic Study of Dispersion Polymerization via CB[7]@ZnTPOR-catalyzed PET-RAFT Polymerization A reaction stock solution consisting of DAAM (0.86 g, 5.04 mmol), PDMA 36 (95 mg, µmol) and CB[7]@ZnTPOR (2.72 ml of CB[7]@ZnTPOR stock solution, [ZnTPOR] = 185 μm, [CB[7]] = 555 μm) were introduced into a glass tube. The reaction mixture was degassed for 45 min and irradiated in green LED light (8 w, 520 nm) at a stirring of 500 rpm and 20 o C. Aliquots were withdrawn at predetermined time intervals for 1 H NMR and GPC measurements. After polymerization was complete, the irradiation was switched off and the resulting mixture was subjected to air. S3

4 Figure S1. 1 H NMR spectrum of TPOR in DMSO-d 6. Figure S2. UV-vis absorption spectra of TPOR (black line) and ZnTPOR (red line) in water. The concentrations of TPOR and ZnTPOR were 16 µm and 5.2 µm, respectively. S4

5 Figure S3. 1 H NMR spectra of ZnTPOR, CB[7]@ZnTPOR and CB[7] in D 2 O. The concentrations of ZnTPOR and CB[7] were mm and 2.5 mm, respectively. As is shown in Figure S3, upon the addition of CB[7], the proton signals of ZnTPOR in D 2 O (between 6 and 10 ppm) disappeared, which suggested that ZnTPOR was located in the hydrophobic microenvironment constructed by CB[7]. Figure S4. A) UV-vis absorption spectra of ZnTPPS mixed with ETTC in water. The concentrations of ETTC and ZnTPPS were 26.6 µm and 2.58 µm, respectively. B) UV-vis absorption spectra of TPOR mixed with ETTC. The concentrations of ETTC and TPOR were 28.5 µm and 28 µm, respectively. S5

6 Figure S5. UV-vis absorption spectra of ETTC and in water. The concentrations of ETTC and CB[7] were 6.0 µm and 60 µm, respectively. Figure S6. Plot of the ratio I o /I versus ETTC concentration. (I o and I correspond to the emission intensity of ZnTPOR in the absence and presence of ETTC, respectively.) The concentration of ZnTPOR was 5.2 µm. The concentrations of ETTC were 0, 12, 16, 20 and 40 µm, respectively. S6

7 Figure S7. Fluorescence spectra of ZnTPOR in water mixed with 20 µm ETTC and varying amounts of CB[7]. The concentration of ZnTPOR was 5.2 µm. Figure S8. Plot of the ratio I o /I versus the concentration of CB[7]. (I o and I correspond to the emission intensity of ZnTPOR mixed 20 µm ETTC in the absence and presence of CB[7], respectively.) The concentration of ZnTPOR was 5.2 µm. The concentrations of CB[7] were 0, 5.2, 10.4 and 15.6 µm, respectively. S7

8 Table S1. Summary of PDMAs synthesized by ZnTPOR-catalyzed RAFT polymerization using different concentrations of ZnTPOR in the absence of CB[7] [a] Entry [ZnTPOR] (µm) Time (h) Conv. % Actual DP M th (kg/mol) M n (kg/mol) M w /M n / / / / [a] Conditions: [DMA]/[ETTC] = 200 : 1, [DMA] = 30% w/v, green LED light (8 w, 520 nm), water, 20 o C, 4 h. Table S2. Summary of PDMAs synthesized by CB[7]@ZnTPOR-catalyzed RAFT polymerization using different concentrations of ZnTPOR [a] Entry [ZnTPOR] (µm) Time (h) Conv. % Actual DP M th (kg/mol) M n (kg/mol) M w /M n / / / / [a] Conditions: [DMA]/[ETTC] = 200 : 1, [CB[7]]/[ZnTPOR] = 4 : 1, [DMA] = 30% w/v, green LED light (8 w, 520 nm), water, 20 o C, 4h. S8

9 Figure S9. Fluorescence spectra of ZnTPOR in water: concentrations of CB[7]. [CB[7]]/[ZnTPOR] = 4 : 1. A) in the absence of CB[7]; B) in the presence of different Figure S10. UV-vis absorption spectra of ZnTPOR in water: different concentrations of CB[7]. [CB[7]]/[ZnTPOR] = 4 : 1. A) in the absence of CB[7]; B) in the presence of S9

10 Figure S11. Dependence of molecular weight on DP of PDMAs synthesized via RAFT polymerization catalyzed by different concentrations of ZnTPOR in the absence of CB[7]. [DMA]/[ETTC] = 200 : 1, green LED light, 8 w, 520 nm, 20 o C, 4 h. Figure S12. GPC traces of PDMAs synthesized via RAFT polymerization catalyzed by different concentrations of ZnTPOR in the absence of CB[7]. [DMA]/[ETTC] = 200 : 1, green LED light, 8 w, 520 nm, 20 o C, 4 h. S10

11 Figure S13. GPC traces of (meth)acrylate polymers synthesized by PET-RAFT polymerization under conditions: [ETTC]/[monomer]/[ZnTPOR]/[CB[7]] = 1 : 200 : 0.01 : 0.03, [M] = 30% w/v, green LED light (8 w, 520 nm), water, 20 o C. Table S3. Summary of PPEGA, PPEGMA and PHEA synthesized by CB[7]@ZnTPOR-catalyzed RAFT polymerization [a] Entry [ZnTPOR] (µm) Time (h) Conv. % Actual DP M th (kg/mol) M n (kg/mol) M w /M n PPEGA PPEGMA PHEA [a] Conditions: [Monomer]/[ETTC] = 200 : 1, [DMA] = 30% w/v, green LED light (8 w, max = 520 nm), water, 20 o C. S11

12 Figure S14. Results of polymerization of DMA (30% w/v) in water at 20 o C utilizing ZnTPOR as the photo-redox catalyst, [ETTC]/[DMA]/[ZnTPOR] = 1 : 200 : A) Monomer conversion vs time; B) plot of pseudo-first-order kinetics of polymerization; C) molecular weights and dispersities of PDMAs with monomer conversion; D) GPC traces of PDMAsofdifferent polymerization times (monomer conversions). S12

13 Figure S15. Results of polymerization of DMA (30% w/v) in water at 20 o C utilizing CB[7]@ZnTPOR as the photo-redox catalyst, [ETTC]/[DMA]/[ZnTPOR]/[CB[7]] = 1 : 200 : 0.01: A) Monomer conversion vs time; B) plot of pseudo-first-order kinetics of polymerization; C) molecular weights and dispersities of PDMAs with monomer conversion; D) GPC traces of PDMAs of different polymerization times (monomer conversions). S13

14 Figure S16. Results of polymerization of DMA (30% w/v) in water at 20 o C utilizing CB[7]@ZnTPOR as the photo-redox catalyst, [ETTC]/[DMA]/[ZnTPOR]/[CB[7]] = 1 : 200 : 0.01: A) Monomer conversion vs time; B) plot of pseudo-first-order kinetics of polymerization; C) molecular weights and polydispersities of PDMAs with monomer conversion; D) GPC traces of PDMAs of different polymerization times (monomer conversions). S14

15 Figure S17. Results of polymerization of DMA (30% w/v) in water at 20 o C utilizing CB[7]@ZnTPOR as the photo-redox catalyst, [ETTC]/[DMA]/[ZnTPOR]/[CB[7]] = 1 : 200 : 0.01: A)Monomer conversion vs time; B) plot of pseudo-first-order kinetics of polymerization; C) molecular weights and polydispersities of PDMAs with monomer conversion; D) GPC traces of PDMAs of different polymerization time (monomer conversions). Table S4. Summary of PDMAs of different target DPs synthesized by PET-RAFT polymerization catalyzed by CB[7]@ZnTPOR under green light irradiation in water. [a] Entry [DMA]/[ETTC] [DMA] w/v % Time (h) Conv. % Actual DP M th (kg/mol) M n (kg/mol) M w/m n [a] Conditions: [ETTC]/[ZnTPOR]/[CB[7]] = 1 : 0.01 : 0.03, [ZnTPOR] = 46.8 µm, green LED light (8 w, 520 nm) water, 20 o C. S15

16 Figure S18. PDMAs of different target DPs synthesized by PET-RAFT polymerization catalyzed by under green light irradiation in water. A) GPC traces and B) dependence of molecular weight on DP (please refer Table S4 for synthetic conditions). Figure S19. Results of light on-off polymerizations of DMA (20% w/v) in water at 20 o C utilizing CB[7]@ZnTPOR as the photo-redox catalyst, [ETTC]/[DMA]/[ZnTPOR]/[CB[7]] = 1 : 200 : 0.01 : A) Plot of pseudo-first-order kinetics of polymerization with light on; B) GPC traces of two representative PDMAs. Green LED light (8 w, 520 nm). Figure S20. GPC trace of PDMA synthesized by CB[7]@ZnTPOR-catalyzed RAFT polymerization in the presence of oxygen. [DMA]/[ETTC]/[ZnTPOR]/[CB[7]] = 200:1: 0.01: 0.03, [DMA] w/v 30%, green LED light, 8 w, 520 nm, 20 o C. After polymerization of 20 h, the monomer conversion was 98%. S16

17 Table S5. Summary of PDMA multiblock homopolymers synthesized via successive chain extensions [a] Cycle Target DP [DMA] w/v % Time (h) Conv. % M n (kg/mol) M w /M n [a] Conditions: [ETTC]/[ZnTPOR]/[CB[7]] = 1 : 0.01 : 0.03, [ZnTPOR] = 46.8 µm, green LED light (8 w, 520 nm) water, 20 o C. Table S6. Summary of PDMA 36 -PDAAM x block copolymer nanoparticles synthesized by CB[7]@ZnTPOR-catalyzed PET-RAFT dispersion polymerization in water under green light irradiation [a] Entry ] [DAAM]/[PDMA 36]/[ZnTPOR]/[CB[7]] [Solids]% CH 3CN content (%) Time (h) Conv. % Actual DP D h (nm)/pdi [b] : 1 : 0.01: / : 1 : 0.02 : /0.22 [a] Conditions: green LED light (8 w, 520 nm), [CB[7]]/[ZnTPOR] = 3:1, water, 20 o C. [b] Hydrodynamic diameters (D h ) and polydispersity (PDI) determined by DLS. S17

18 Figure S21. Results of dispersion polymerization of DAAM (35% solids) in water at 20 o C utilizing CB[7]@ZnTPOR as the photo-redox catalyst, [DAAM]/[PDMA 36 ]/[ZnTPOR]/[CB[7]] = 1 : 200 : 0.02: A) Monomer conversion vs time; B) plot of pseudo-first-order kinetics of polymerization; C) molecular weights and dispersities of PDMA 36 -PDAAM X block copolymers with monomer conversion; D) GPC traces of PDMA 36 (0 h) and PDMA 36 -PDAAM X block copolymers of different polymerization time. REFERENCES 1. Shen, W.; Qiu, Q.; Wang, Y.; Miao, M.; Li, B.; Zhang, T.; Cao, A.; An, Z. Hydrazine as a Nucleophile and Antioxidant for Fast Aminolysis of RAFT Polymers in Air. Macromol. Rapid Commun. 2010, 31, Liu, K.; Liu, Y.; Yao, Y.; Yuan, H.; Wang, S.; Wang, Z.; Zhang, X. Supramolecular Photosensitizers with Enhanced Antibacterial Efficiency. Angew. Chem. Int. Ed. 2013, 52, Saiki, Y.; Amao, Y. Bio-mimetic hydrogen production from polysaccharide using the visible light sensitization of zinc porphyrin. Biotechnol. Bioeng. 2003, 82, S18

Supporting Information

Supporting Information UCST or LCST? Composition-Dependent Thermoresponsive Behavior of Poly(N-Acryloylglycinamide-co-Diacetone Acrylamide) Wenhui Sun, Zesheng An*, Peiyi Wu * Experimental Materials Glycinamide