1-(Phenanthrolo[5,6-d]imidazol-2-yl)-3-(acenaphthro[4,5-d]imidazol-2-yl)benzene

2-(3-formylphenyl)imidazo[4,5-f][1,10]phenanthroline was prepared by a previously published method [1]. A mixture of 2-(3-formylphenyl)imidazo[4,5-f][1,10]phenanthroline (0.2 g, 0.62 mmol), acenaphthenequinone (0.124 g, 0.68 mmol), ammonium acetate (0.713 g, 9.3 mmol) and glacial acetic acid (10 cm³) was refluxed for about 3 h. The cooled solution was filtered and then poured into 100 cm³ ether. The crude product was collected and purified on alumina with ethanol-toluene (1:4 v/v) as eluent to give the title compound as a yellow powder. (0.159 g, yield: 52.7%).

¹H NMR (500 MHz, d₆-DMSO): 13.84 (br, 2H), 9.24 (s, 1H), 8.93 (d, 2H, J = 8), 8.91 (d, 2H, J = 7.5), 8.69 (d, 1H, J = 8), 8.39 (d, 1H, J = 8), 8.21 (d, 1H, J = 8), 7.85 (m, 2H), 7.78 (dd, 2H, J = 5), 7.73 (dd, 2H, J = 4), 7.68 (t, 1H, J = 8), 7.60 (t, 1H, J = 7).

¹³C NMR (125 MHz, d₆-DMSO): 150.2, 147.9, 143.7, 136.8, 135.7, 131.7, 131.2, 130.9, 129.9, 129.5, 129.1, 128.8, 128.1, 127.8, 126.6, 125.9, 125.4, 123.6, 123.0, 122.8, 119.5.

IR (KBr. cm^-1): 3392s, 1603s, 1593m, 1542m, 1474m, 1438m, 1402m, 1278s, 1202m, 1073m, 1015m, 806m, 777s, 739s, 678w, 624w,

UV-Vis (l, nm, in ethanol): 227, 290, 319.

FAB-MS ([M+1]⁺): 487.