Boron and transition metal compounds derived from 2-uroylbenzimidazole

The coordination sites of 2-uroylbenzimidazole 1 toward diphenylborinic acid, as well as zinc, cadmium, copper, nickel and cobalt chlorides, bromides, and nitrates were investigated. The ligand is bonded in monodentate mode to ZnCl2, ZnBr2, CdCl2, CdBr2, and Cd(NO3)2, and in bidentate mode to all others. With diphenylborinic acid, two heterocycles are formed; in one, the boron is bonded to imidazole and the terminal NH2 group, and in the other the boron is bonded to imidazole and to the oxygen atom. Boron, zinc, and cadmium derivatives were studied by NMR spectroscopy. The X-ray diffraction structure of 2-uroylbenzimidazole is reported.