Reaction Steps
To a dry pressure Schlenk tube equipped with a magnetic stir bar was added 2-(4-phenylpyridin-2-yl)-9H-carbazole (676 mg, 2.11 mmol, 1.0 eq), 2-bromo-9-(4-tert-butylpyridin-2-yl)-9H-carbazole (958 mg, 2.53 mmol, 1.2 eq), Pd2(dba)3 (77 mg, 0.084 mmol, 0.04 eq), JohnPhos (50 mg, 0.169 mmol, 0.08 eq) and tBuONa (324 mg, 3.38 mmol, 1.6 eq). Then the tube was evacuated and back-filled with nitrogen, and the evacuation and back-fill procedure was repeated twice. Then dry solvent toluene (10 mL), dioxane (10 mL) were added under the protection of nitrogen. The tube was sealed and the mixture was stirred in an oil bath at a temperature of 95-105° C. for 43 hours. Then the mixture was cooled to ambient temperature. The solvent was removed under reduced pressure and the residue was purified through column chromatography on silica gel using hexane and ethyl acetate (10:1-8:1-5:1) as an eluent to obtain the desired product, 9-(4-tert-butylpyridin-2-yl)-2′-(4-phenylpyridin-2-yl)-9H-2,9′-bicarbazole Ligand N3NPh-ptb, as a brown solid (1175 mg in 90% yield). 1H NMR (DMSO-d6, 400 MHz): δ 1.15 (s, 9H), 7.25 (t, J=8.0 Hz, 1H), 7.31 (dd, J=5.2, 1.6 Hz, 1H), 7.34-7.57 (m, 9H), 7.74 (s, 1H), 7.78-7.82 (m, 3H), 7.91 (d, J=1.6 Hz, 1H), 8.11 (d, J=8.4 Hz, 1H), 8.21 (s, 1H), 8.24 (d, J=8.0 Hz, 1H), 8.29 (s, 1H), 8.31 (d, J=8.4 Hz, 2H), 8.45 (d, J=6.0 Hz, 1H), 8.51 (d, J=8.0 Hz, 1H), 8.57 (d, J=4.2 Hz, 1H). 13C NMR (DMSO-d6, 100 MHz): δ 29.96, 34.72, 108.01, 109.82, 109.85, 111.36, 115.97, 117.92, 119.14, 119.31, 119.80, 119.92, 120.23, 120.72, 120.84, 121.29, 122.00, 122.39, 122.94, 123.02, 123.45, 126.63, 126.84, 127.05, 129.06, 129.16, 134.83, 136.92, 137.49, 139.73, 139.78, 141.13, 141.47, 148.33, 149.39, 149.97, 150.55, 157.15, 163.08.
