2.3 Synthesis
The synthetic routes of the compounds 1–3, monomer 1–2 and PCZBTA-TBZ were illustrated in Scheme 1. Compound 1, compound 3 and the monomer 2 were prepared using established procedure[29–31].
2.3.1 4,7-Dibromo-2-(6-bromohexyl)-2H-benzo[d[1, 2, 3]triazole (2). Compound 1 (5.9583 g, 21 mmol) and HBr (20 mL) was stirred for 1 h at 100℃. Then, Br2 (4 mL) was slowly added with a constant pressure funnel, and the mixture was refluxed at 135℃ for 12 h. After cooling, the pH was adjusted to neutrality and the mixture was extracted with CHCl2. The organic layer was washed by water, and dried with anhydrous Na2SO4. The solvent was removed by rotary evaporator. The crude product was purified by column chromatography (silica gel, 200–300 mesh, petroleum ether: dichloromethane = 5:4, v/v) to give a white solid (5.9796 g, 63.65% yield).1H NMR (400 MHz, CDCl3) δ (ppm): 7.45 (s, 2H), 4.79 (t, J = 7.3 Hz, 2H), 3.40 (t, J = 6.7 Hz, 2H), 2.18 (p, J = 7.4 Hz, 2H), 1.87 (dt, J = 14.5, 6.8 Hz, 2H), 1.56–1.48 (m, 2H), 1.42 (q, J = 8.8, 8.1 Hz, 2H). mp: 64.6–65.1℃.
2.3.2 5-(1-(6-(4,7-Dibromo-2H-benzo[d][1, 2, 3]triazol-2-yl)hexyl)-1H-benzo[d]imidazol-2-yl)thiazole (Monomer1). Under an argon atmosphere, a mixture of thiabendazole (0.3819 g, 1.9 mmol), K2CO3 (0.7875 g, 5.6 mmol) and DMF (15 mL) was stirred at 95°C for 2 h, cooling to room temperature and adding with compound 2 (1.2706 g, 2.8 mmol). Then the mixture was stirred for 12 h at 95℃. After cooling to room temperature, the reaction solution was extracted with CH2Cl2. The organic layer was washed by water, and dried over anhydrous Na2SO4. The solvent was removed by rotary evaporator. The crude product was purified by column chromatography (silica gel, 200–300 mesh, petroleum ether: dichloromethane = 5:1, v/v) to give a yellow solid (0.7703 g, 71.9% yield). 1H NMR (400 MHz, CDCl3) δ (ppm): 8.65 (d, J = 5.0 Hz, 1H), 8.40 (d, J = 8.0 Hz, 1H), 7.82 (t, J = 7.7 Hz, 2H), 7.40 (d, J = 6.9 Hz, 2H), 7.33–7.28 (m, 2H), 4.77 (dt, J = 23.9, 7.3 Hz, 4H), 2.10 (p, J = 7.1 Hz, 2H), 1.88 (q, J = 7.3 Hz, 2H), 1.40 (dq, J = 9.7, 5.9, 4.7 Hz, 4H). 13C NMR (101 MHz, CDCl3) δ (ppm): 153.11, 147.79, 146.51, 143.77, 142.59, 135.68, 129.66, 123.11, 122.72, 121.46, 119.64, 110.04, 110.01, 77.39, 77.07, 76.75, 57.31, 44.89, 29.96, 29.71, 26.13, 26.02. HRMS (ESI+) [M + H]+: calculated for C22H21Br2N6S+: 558.9910; found 558.9913. mp: 120.8-121.7℃.
2.3.3 9-Octyl-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-carbazole (Monomer 2). Under an argon atmosphere, compound 3 (0.8016 g, 1.1 mmol), bis(pinacolato)diborane (1.6833 g, 1.1 mmol), potassium acetate (1.0833 g, 1.1 mmol) and DMF (17 mL) were stirred at room temperature for 20 min, then [1,1'-Bis(diphenylphosphino)ferrocene] dichloropalladium (II) (0.0942 g, 0.01 mmol) was added. The mixture was stirred at 60°C for 12 h. After cooling to room temperature, the mixture was extracted with ether. The organic layer was dried with anhydrous Na2SO4 and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (silica gel, 200–300 mesh, dichloromethane: petroleum ether = 2:1) to give a white solid (0.31 g, 55% yield).1H NMR (400 MHz, CDCl3) δ (ppm): 8.12 (d, J = 7.8 Hz, 2H), 7.88 (s, 2H), 7.68 (d, J = 7.8 Hz, 2H), 4.38 (t, J = 7.4 Hz, 2H), 1.94–1.84 (m, 2H), 1.40 (s, 24H), 1.26 (s, 10H), 0.86 (d, J = 7.0 Hz, 3H). 13C NMR (101 MHz, CDCl3) δ 140.32, 124.95, 124.73, 119.92, 115.15, 83.68, 42.77, 31.73, 29.10, 29.07, 27.00, 24.83, 22.54, 14.02. mp: 181.8-182.9℃.
2.3.4 Polymer PCZBTA-TBZ
The polymer PCZBTA-TBZ was synthesized by Suzuki cross-coupling reaction. Under argon atmosphere, monomer 1 (0.1590 g, 0.3 mmol), monomer 2 (0.1680 g, 0.3 mmol), K2CO3 (2 mol/L, 2 mL) and two drops of methyltrioctyl ammonium chloride were added to toluene (8 mL) and stirred for 20 minutes after complete deoxygenation. Then Pd(OAc)2 (0.0033 g, 0.0150 mmol) and tricyclohexylphosphine (0.0066 g, 0.0235 mmol) were added and the mixture was vigorously stirred at 90°C for 24 h. After cooling to room temperature, the solution was poured into methanol (300mL) and the precipitated polymer was filtered. The product was extracted with methanol for 48 h and dried under vacuum to afford a yellow solid (0.1193 g, 58.74% yield).1H NMR (400 MHz, CDCl3) δ (ppm): 1H NMR (400 MHz, CDCl3) δ (ppm): 8.80 (d, J = 44.6 Hz, 1H), 8.37 (d, J = 11.7 Hz, 1H), 8.24 (dd, J = 16.9, 7.5 Hz, 3H), 8.14–7.92 (m, 3H), 7.88–7.67 (m, 4H), 7.43–7.30 (m, 2H), 4.98–4.77 (m, 2H), 4.77–4.66 (m, 2H), 4.56–4.38 (m, 2H), 2.06–1.79 (m, 8H), 1.37–1.13 (m, 12H), 0.79 (d, J = 5.2 Hz, 3H).13C NMR (101 MHz, CDCl3) δ (ppm): 153.14, 153.11, 153.09, 152.88, 144.00, 143.97, 141.59, 141.57, 140.83, 125.12, 123.23, 123.10, 122.79, 122.75, 122.72, 122.64, 121.60, 120.73, 120.71, 120.67, 119.99, 119.54, 119.49, 119.47, 109.96, 109.88, 109.25, 109.18, 44.89, 35.49, 31.89, 29.65, 29.51, 29.26, 29.13, 27.45, 26.09, 22.60, 22.58, 14.06, 14.00, 1.03. GPC: Mw = 10089, Mn = 4846, and polydispersity index (PDI) = 2.08.