2.2. Synthesis and characterization of the compounds
10-Butyl-3-(1-(4-( tert -butyl)phenyl)-4,5-diphenyl-1 H -imidazol-2-yl)-10 H -phenothiazine (PTZ-PIM): In a 250 mL three-necked flask, benzil (0.82 g, 3.90 mmol), 4-tert-butylaniline (0.64 g, 4.29 mmol), 10-butyl-10H-phenothiazine-3-carbaldehyde (1.00 g, 3.53 mmol) and CH3COONH4 (4.08 g, 52.93 mmol) were dissolved in 50 mL of glacial acetic acid, and then it was stirred at 120°C for 24 h under a nitrogen atmosphere. After cooling to room temperature, the reaction mixture was poured into ice water and filtered to obtain a yellow solid. The crude product was purified by silica gel chromatography using dichloromethane/petroleum ether (1:3, v/v) to obtain a pale yellow solid (1.90 g, 89%). m.p. > 240°C. 1H NMR (500 MHz, CDCl3, δ, ppm): 7.59 (d, J = 7.6 Hz, 2H, Ar-H), 7.28 (d, J = 8.6 Hz, 2H, Ar-H), 7.25−7.15 (m, 8H, Ar-H), 7.12 (d, J = 7.7 Hz, 3H, Ar-H), 7.08 (s, 1H, Ar-H), 7.03 (d, J = 7.2 Hz, 1H, Ar-H), 6.95 (d, J = 8.5 Hz, 2H, Ar-H), 6.78 (d, J = 8.8 Hz, 2H, Ar-H) 3.78 (t, J = 7.0 Hz, 2H, N-CH2),1.76−1.70 (m, 2H, -CH2-), 1.45−1.37 (m, 2H, -CH2-), 1.29 (s, 9H, -C(CH3)3), 0.92 (t, J = 7.5 Hz, 3H, -CH3). 13C NMR (126 MHz, CDCl3, δ, ppm): 151.7, 138.1, 134.5, 134.3, 131.1, 130.7, 128.3, 128.2, 128.0, 127.8, 127.5, 127.2, 126.6, 126.1, 115.3, 114.7, 34.8, 31.2, 20.1, 13.9. HRMS: Calcd. for C41H39N3S, 606.2937 [M+H]+; Found: 606.2937. Anal. Calcd. for C41H37N3S: C,81.28; H, 6.49; N, 6.94. Found: C, 81.43; H, 6.46; N, 6.91.
10-Butyl-3,7-bis(1-(4-( tert -butyl)phenyl)-4,5-diphenyl-1 H -imidazol-2-yl)-10 H -phenothiazine (PIM-PTZ-PIM): In a 250 mL three-necked flask, benzil (1.86 g, 8.85 mmol), 4-tert-butylaniline (1.44 g, 9.65 mmol), 10-butyl-10H-phenothiazine-3,7-dicarbaldehyde (1.00 g, 3.21 mmol) and CH3COONH4 (9.30 g, 0.12 mol) were dissolved in 60 mL of glacial acetic acid, and then the reaction mixture was stirred at 120°C for 24 h under a nitrogen atmosphere. After cooling to room temperature, the reaction mixture was poured into ice water and filtered to obtain a white solid. The crude product was purified by silica gel chromatography using dichloromethane/petroleum ether (1:1, v/v) to obtain a pale white solid (2.15 g, 70%). m. p. > 250°C. 1H NMR (500 MHz, CDCl3, δ, ppm): 7.57 (d, J = 7.1 Hz, 3H, Ar-H), 7.39 (d, J = 8.6 Hz, 2H, Ar-H), 7.32 (d, J = 8.7 Hz, 3H, Ar-H), 7.28 (d, J = 8.6 Hz, 5H, Ar-H), 7.25 −7.14 (m, 12H, Ar-H), 7.11 (d, J = 7.8 Hz, 3H, Ar-H), 7.00 (s, 2H, Ar-H), 6.94 (d, J = 8.6 Hz, 3H, Ar-H), 6.61 (d, J = 8.7 Hz, 1H, Ar-H), 3.72 (t, J = 7.2 Hz, 2H, N-CH2-), 1.71−1.61 (m, 2H, -CH2-), 1.43−1.36 (m, 2H, -CH2-), 1.29 (s, 18H, -C(CH3)3), 0.91 (t, J = 7.5 Hz, 3H, -CH3). 13C NMR (126 MHz, CDCl3, δ, ppm): 168.3, 151.8, 147.2, 146.1, 144.4, 135.3, 134.3, 131.1, 130.7, 130.6, 128.6, 128.3, 128.1, 127.9, 127.8, 127.5, 127.3, 126.6, 126.1, 125.8, 123.9, 119.8, 114.5, 47.1, 34.7, 34.4, 31.4, 31.3, 28.7, 24.5, 20.0, 13.8. HRMS: Calcd. for C66H61N5S, 956.4720 [M+H]+; Found: 956.4720. Anal. Calcd. for C66H61N5S: C, 82.89; H, 6.43; N, 7.32. Found: C, 83.03; H, 6.45; N, 7.30.