Structural and Electrochemical Studies of Some Cobalt(III) Complexes of 2-Aminomethylbenzimidazole and 2-(N-Methylaminomethyl)benzimidazole

Abstract

A number of mixed-ligand cobalt(III) complexes containing either the ligand 2-aminomethylbenzimidazole (ambi) or its N-methyl derivative, namely 2-(N-methylaminomethyl)benzimidazole (mambi), have been prepared in relatively low yield; in particular, the complexes [Co(ambi)(acac)2] Cl, [Co(ambi)(Clacac)2] Cl, K[Co(ambi)(ox)2],[Co(ambi)2(acac)] (ClO4)2, [Co(mambi)(acac)2] Cl and [Co(mambi)(Clacac)2 ]Cl (acac = acetylacetonate, Clacac = 3-chloroacetylacetonate, ox = oxalate). The reduction potentials of these complexes have been measured in order to assess whether molecules of this type could be potential redox-activated hypoxic cell selective anticancer agents. The complex [Co(ambi)(acac)2] Cl.4·1H2O was characterized by single-crystal X-ray crystallography: a 19·425(1), b 17·734(1), c 15·979(1) Å, β 117·52(1)˚, monoclinic, space group C 2/c (No. 15)