Reaction Steps
A mixture of 2,2′-dipyridylamine (5.27 g, 30.76 mmol), (4-bromophenyl)-di(4-pyridyl)amine (2.50 g, 7.69 mmol), anhydrous potassium carbonate (2.66 g, 19.23 mmol), bronze powder (4.93 g, 77.64 mmol), 18-crown-6 (200 mg, 0.76 mmol), and DMF (125 mL) was heated at 145 degrees C. under nitrogen for 30 hours. The reaction was cooled and worked up by a procedure similar to that for L1. A yellowish solid was collected from a silica gel column, and was further purified by recrystallization from dichloromethane and petroleum ether, to afford a white solid of N,N-di(2-pyridyl)-N′,N′-di(4-pyridyl)-1,4-phenylenediamine (L2, 1.32 g, yield: 41%). 1H NMR (CDCl3, Bruker 400 MHz): 8.43 (d, J=4.4 Hz, 4H, pyridyl-H), 8.37 (d, J=3.6 Hz, 2H, pyridyl-H), 7.60-7.65 (m, 2H, pyridyl-H), 7.21 (d, J=8.8 Hz, 2H, phenylene-H), 7.14 (d, J=8.8 Hz, 2H, phenylene-H), 6.98-7.09 (m, 8H, pyridyl-H). Anal. Calcd (%) for C26H20N6: C, 74.98; H, 4.84; N, 20.18. Found: C, 74.53; H, 4.72; N, 19.89. IR (KBr pellet, cm−1): 1575(vs), 1505(s), 1490(s), 1467(s), 1431(vs), 1324(s), 1305.13 (s), 1276(s), 1218(m), 1163(w), 1103(w), 991(m), 811(m), 777(m), 737(w), 654(w), 622(m), 530(m).
