Supporting Information

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1 Supporting Information A Rational Design of Highly Controlled Suzuki-Miyaura Catalyst-Transfer Polycondensation for Precision Synthesis of Polythiophenes and their Block Copolymers: Marriage of Palladacycle Precatalysts with MIDAboronates Kyeong-Bae Seo,, In-Hwan Lee,, Jaeho Lee,, Inho Choi, and Tae-Lim Choi *, Department of Chemistry, Seoul National University, Seoul, 08826, Korea. Department of Chemistry, Ajou University, Suwon, 16499, Korea. These authors contributed equally. * tlc@snu.ac.kr S1

2 Table of contents Materials and analytical methods Experimental procedures for the preparation of monomers and polymers Ligand screening for catalyst-transfer Suzuki-Miyaura reaction Kinetic analysis of product ratio in a small molecule reaction Synthesis of P3HT in the presence of 2-bromothiophene Condition screening for the synthesis of P3HT from MIDA boronates Regioregularity of P3HT and P3EHT Chain-end analysis of P3HT from Bpin-based monomer Kinetic analysis of one-shot copolymerization for P3EHT-b-P3HT pp S3 S3 S6 S7 S7 S8 S9 S9 S10 1 H and 13 C NMR spectra of monomers and polymers S11 SEC RI traces of polymers S15 S2

3 Materials Unless otherwise noted, all reagents were purchased from commercial sources and used without further purification. Tetrahydrofuran (THF) was distilled over sodium and benzophenone, and degassed by argon bubbling for 10 minutes before the polymerization. 5-Bromo-4-n-hexylthien-2-ylpinacol-boronate (M3), 10b 5-bromo-4-n-hexylthien-2-yl-MIDA-boronate (M4), 10b and 5-bromothien-2- yl-mida-boronate (M7) 9a were prepared by the previously reported methods. General analytical information NMR spectra were recorded by Varian/Oxford As-500 (500 MHz for 1 H NMR), Agilent 400-MR DD2 Magnetic Resonance System (400 MHz for 1 H NMR, 162 MHz for 31 P NMR), and Bruker DRX-300 (75 MHz for 13 C NMR) spectrometers. THF Size exclusion chromatography (SEC) for polymer molecular weight analysis was carried out with Waters system (1515 pump, 2414 refractive index detector and 2489 UV detector) and Shodex SEC LF-804 column eluted with THF (SEC grade, Honeywell Burdick & Jackson). For the MALLS-VIS-RI analysis, Wyatt triple detector and Dawn 8+/Viscostar II/Optilab T-rEX were used. Flow rate was 1.0 ml/min and temperature of the column was maintained at 35 C. Samples were diluted in wt% by THF and filtered through a 0.20 μm PTFE filter before injection into the SEC. The molar masses of polymers were measured by Bruker Daltonics autoflex II TOF/TOF using dithranol as a matrix. Preparation and characterization of monomers and polymers (a) 5-Bromo-4-(2-ethylhexyl)thien-2-yl-MIDA-boronate (M5) M5 was prepared by the slightly modified procedure from the previous literature. 10b 1 H NMR (500 MHz, CD 2Cl 2) δ 7.00 (s, 1H), 3.91 (dd, J = 16.5, 2.0 Hz, 2H), 3.81 (dd, J = 16.5, 2.1 Hz, 2H), 2.69 (s, 3H), 2.52 (d, J = 7.2 Hz, 2H), 1.61 (m, 1H), 1.30 (m, 8H), 0.89 (t, J = 7.4 Hz, 6H); 13 C NMR (75 MHz, CDCl 3) δ , , , , 61.71, 47.84, 39.96, 33.76, 32.63, 28.84, 25.77, 23.16, 14.25, 10.90; ESI-MS calculated for [M+Na] , found (b) 5-Bromo-4-(2-ethylhexyl)thien-2-yl-pinacol-boronate (M6) M6 was prepared by the slightly modified procedure from the previous literature. 10b 1 H NMR (500 MHz, CD 2Cl 2) δ 7.24 (s, 1H), 2.48 (d, J = 7.2 Hz, 2H), (m, 1H), (m, 20H), 0.86 (t, J = 7.2 Hz, 6H); 13 C NMR (75 MHz, CDCl 3) δ , , , 84.34, 75.15, 40.13, 33.60, 32.60, 28.90, 25.69, 24.97, 24.84, 23.14, 14.24, 10.90; ESI-MS calculated for [M+Na] , found (c) Synthesis of P3HT using M3 as a monomer S3

4 To a round-bottom flask equipped with a magnetic stir bar, Buchwald G3 precatalyst (0.008 mmol), 2- iodotoluene ( mmol), ligand (0.012 mmol), and K 3PO 4 (1.2 mmol) were added. The flask was evacuated and backfilled with argon three times. Degassed THF (2 ml) and H 2O (0.3 ml) were then added. The mixture was heated and stirred at 50 o C for 1 h to prepare externally initiated catalyst. M3 (0.2 mmol where M/I = 25/1) in degassed THF (12 ml) was then added to the flask, and the polymerization was left to stir at room temperature for h. The polymerization was quenched with 6N HCl solution (5 ml). The crude reaction mixture was diluted with CHCl 3, washed with brine, dried over anhydrous MgSO 4, and concentrated under reduced pressure. The polymer was purified by precipitation into methanol. The precipitate was collected by filtration, washed with methanol, and dried under vacuum. (d) Synthesis of P3HT (or P3EHT) using M4 (or M5) as a monomer To a round-bottom flask equipped with a magnetic stir bar, Buchwald G3 precatalyst (0.008 mmol), aryl iodide ( mmol), ligand (0.012 mmol), and K 3PO 4 (1.2 mmol) were added. The flask was evacuated and backfilled with argon three times. Degassed THF (2 ml) and H 2O (0.72 ml) were then added. The mixture was heated and stirred at 50 o C for 15 minutes (for 4-iodobenzonitrile) or 1 h (for 2-iodotoluene) to prepare externally initiated catalyst. M4 or M5 (0.2 mmol where M/I = 25/1) in degassed THF (17 ml) was then added to the flask, and the polymerization was left to stir at 45 o C for h. The polymerization was quenched with 6N HCl solution (5 ml). The crude reaction mixture was diluted with CHCl 3, washed with brine, dried over anhydrous MgSO 4, and concentrated under reduced pressure. The polymer was purified by precipitation into methanol. The precipitate was collected by filtration, washed with methanol, and dried under vacuum. M n and PDI values of polymers were consistent before and after precipitation into methanol (e.g. before precipitation: M n = 5.9 kg/mol and PDI = 1.10; after precipitation: M n = 5.8 kg/mol and PDI = 1.12 (determined by THF SEC using MALLS detector); isolated yield = 96%). (e) Synthesis of P3HT-b-P3EHT by the sequential monomer addition S4

5 To a round-bottom flask equipped with a magnetic stir bar, RuPhos G3 precatalyst (0.005 mmol), 2- iodotoluene ( mmol), RuPhos ( mmol), and K 3PO 4 (0.45 mmol) were added. The flask was evacuated and backfilled with argon three times. Degassed THF (2 ml) and H 2O (0.27 ml) were then added. The mixture was heated and stirred at 50 o C for 15 minutes to prepare externally initiated catalyst. M4 (0.075 mmol) in degassed THF (5.1 ml) was then added to the flask, and the polymerization was left to stir at 45 o C for 16 h. Subsequently, M5 (0.15 mmol) in degassed THF (7.1 ml) and K 3PO 4 (0.45 mmol) in degassed H 2O (0.54 ml) were added to the flask, and the polymerization was left to stir at 45 o C for 16 h. The polymerization was quenched with 6N HCl solution (5 ml). The crude reaction mixture was diluted with CHCl 3, washed with brine, dried over anhydrous MgSO 4, and concentrated under reduced pressure. The polymer was purified by precipitation into methanol. The precipitate was collected by filtration, washed with methanol, and dried under vacuum (isolated yield: 91%). (f) Synthesis of P3EHT-b-P3HT by the one-shot method To a round-bottom flask equipped with a magnetic stir bar, SPhos G3 precatalyst ( mmol), 2- iodotoluene ( mmol), SPhos (0.01 mmol), and K 3PO 4 (1.2 mmol) were added. The flask was evacuated and backfilled with argon three times. Degassed THF (2 ml) and H 2O (0.6 ml) were then added. The mixture was heated and stirred at 50 o C for 1 h to prepare externally initiated catalyst. M4 (0.1 mmol) and M6 (0.1 mmol) in degassed THF (10 ml) were then added to the flask, and the polymerization was left to stir at 35 o C for 12 h. The polymerization was quenched with 6N HCl solution (5 ml). The crude reaction mixture was diluted with CHCl 3, washed with brine, dried over anhydrous MgSO 4, and concentrated under reduced pressure. The polymer was purified by precipitation into methanol. The precipitate was collected by filtration, washed with methanol, and dried under vacuum (30 mg, isolated yield: 83%). S5

6 Table S1. Ligand screening for catalyst-transfer Suzuki-Miyaura reaction Entry Pd catalyst (equiv.) Ligand (equiv.) THF/H 2 O (conc., v/v) Molar ratio M1:M2 1 Pd2dba3 (0.02) RockPhos(0.08) 0.03 M, 30/1 100:0 2 Pd2dba3 (0.02) BrettPhos (0.08) 0.03 M, 30/1 100:0 3 Pd2dba3 (0.02) DavePhos (0.08) 0.03 M, 30/1 21:79 4 Pd2dba3 (0.02) tbuxphos(0.08) 0.03 M, 30/1 13:87 5 Pd2dba3 (0.02) tbubrettphos (0.08) 0.03 M, 30/1 9:91 6 Pd2dba3 (0.02) Me4tBuXPhos (0.08) 0.03 M, 30/1 No product 7 a RuPhod Pd G3 (0.04) RuPhos (0.04) 0.03 M, 30/1 0:100 a Ph-B(MIDA) instead of Ph-B(OH) 2 was used. To a round-bottom flask equipped with a magnetic stir bar, Pd 2dba 3 (0.004 mmol), ligand (0.016 mmol), and K 3PO 4 (1.2 mmol) were added. The flask was evacuated and backfilled with argon three times. Degassed THF (2 ml) and H 2O (0.4 ml) were then added. The mixture was heated and stirred at 50 o C for 1 h. 2,5-dibromothiophene (0.2 mmol) and phenylboronic acid (0.1 mmol) in degassed THF (10 ml) was then added to the flask, and the reaction was left to stir at room temperature overnight. The crude reaction mixture was diluted with diethyl ether and analyzed by GC-MS using undecane as an internal standard. S6

7 Table S2. Kinetic analysis of M2:M1 ratio in a small molecule reaction Time (h) GC Yield of M2 a M2:M1 ratio a 0.5 3% >99:1 1 8% >99: % >99: % >99:1 a Molar ratio and yield based on 2,5-dibromothiophene were determined by gas chromatography-mass spectrometry (GC- MS) calibrated using undecane as an internal standard. Table S3. Synthesis of P3HT in the presence of 2-bromothiophene Entry 2-BrTh (x equiv.) Time Mn (PDI) a Isolated yield h 5.0k (1.06) 94% h 5.0k (1.05) 96% h 4.9k (1.06) 96% a Absolute molecular weight was determined by THF SEC using MALLS detector S7

8 Table S4. Condition screening for the synthesis of P3HT Entry M/I R Pd catalyst (mol%) Ligand (mol%) Base (equiv.) Temper ature Time M n (PDI) a Yield b Me Pd 2dba 3 (2) RuPhos (10) K 3PO 4 (6) 45 o C 21 h 9.0 k (1.46) 89% Me RuPhos Pd G3 (4) - K 3PO 4 (6) 45 o C 22 h 6.2 k (1.18) 87% 3 25 H RuPhos Pd G3 (4) RuPhos (6) K 3PO 4 (6) 45 o C 15 h 7.4 k (1.13) 92 % Me RuPhos Pd G3 (4) RuPhos (6) K 3PO 4 (6) 45 o C 15 h 6.0 k (1.14) 90 % NO 2 RuPhos Pd G3 (4) RuPhos (6) K 3PO 4 (6) 45 o C 15 h 14.6 k (1.51) 77 % ,4-CN RuPhos Pd G3 (4) RuPhos (6) K 3PO 4 (6) 45 o C 15 h 6.7 k (1.25) 96 % CN RuPhos Pd G3 (4) RuPhos (6) K 3PO 4 (6) 45 o C 15 h 7.3 k (1.12) 88 % Me RuPhos Pd G3 (2) RuPhos (3) K 3PO 4 (6) 55 o C 20 h 8.8 k (1.35) 91% Me RuPhos Pd G3 (2) RuPhos (3) K 3PO 4 (6) 65 o C 8 h 6.2 k (1.39) 74% Me RuPhos Pd G3 (2) RuPhos (3) NaOH (6) 45 o C 11 h 9.7 k (1.33) 80 % Me RuPhos Pd G3 (2) RuPhos (3) Me RuPhos Pd G3 (2) RuPhos (3) CsF (6) 18-c-6(6) K 3PO 4 (6) 18-c-6(6) 45 o C 20 h 7.7 k (1.58) 86 % 45 o C 11 h - 0 % 13 c 75 4-CN RuPhos Pd G3 (1.3) RuPhos (2) K 3PO 4 (6) 45 o C 15 h 16.0 k (1.30) 91 % 14 d 75 4-CN RuPhos Pd G3 (1.3) RuPhos (2) K 3PO 4 (6) 45 o C 15 h 15.2 k (1.56) 80 % 15 c 75 3,4-CN RuPhos Pd G3 (1.3) RuPhos (2) K 3PO 4 (6) 45 o C 15 h 12.3 k (1.45) 84 % 16 c 75 3-CN RuPhos Pd G3 (1.3) RuPhos (2) K 3PO 4 (6) 45 o C 15 h 13.0 k (1.44) 81 % 17 c 75 3-NO 2 RuPhos Pd G3 (1.3) RuPhos (2) K 3PO 4 (6) 45 o C 15 h 12.7 k (1.40) 85 % a THF SEC calibrated using polystyrene standards. b Isolated yield. c Externally initiated catalyst was prepared for 30 min. d Externally initiated catalyst was prepared for 7 min. e Externally initiated catalyst was prepared for 15 min. S8

9 Figure S1. Regioregularity of P3HT 11a and P3EHT (a) P3HT (b) P3EHT Figure S2. Chain-end analysis of P3HT from M3 by (a) MALDI and (b) 1 H NMR analysis S9

10 Figure S3. Kinetic analysis of one-shot copolymerization for P3EHT-b-P3HT The conversion of M4 and M6 were determined by the change of integral values at 7.24 (M6) and 3.88 ppm (M4) using p-dimethoxybenzene as an internal standard. Degree of polymerization of each block was determined by comparing integral value at 2.50 ppm (o-tolyl chain end) with integral values of polymer methylene groups at 2.73 (P3EHT) and 2.80 ppm (P3HT). S10

11 Figure S4. 1 H and 13 C NMR spectra of monomers and polymers S11

12 S12

13 S13

14 Below is the 1 H NMR spectra (500 MHz, CDCl3) of (a) P3HT macroinitiator from M4 and (b) P3HT-b-P3EHT from (a) and M5 (please see Figure 5 in the manuscript for details). S14

15 Figure S5. SEC RI traces of polymers (a) Table 2 (b) Table 3 All the molecular weights were determined by multi-angle laser light scattering (MALLS) detector, absolute molecular weight determination. S15