Syntheses and crystal structures of mononuclear and dinuclear (pentamethylcyclopentadienyl)iridium(III) complexes containing 2-mercaptobenzimidazole

A reaction of [Cp*IrCl2]2 {Cp* = η5-C5(CH3)5} and 2-mercaptobenzimidazole (H2bimt) in methanol in a 1:2 molar ratio gave a yellow complex of [Cp*IrCl2(H2bimt)]·CH3OH (1). In compound 1 the H2bimt acts as a monodentately S-donating (κS) ligand. A similar reaction of [Cp*IrCl2]2 and H2bimt in the presence of NaOCH3 (molar ratio of 1:2:2) gave an orange product (2) on addition of excess amount of NH4PF6. Compound 2 was composed of an unsymmetrical dinuclear complex cation, [(Cp*IrCl)2(μ-Hbimt)(μ-H2bimt)]+, a PF6− anion, and water molecules of crystallization. In the complex cation, H2bimt bridges two IrIII centers by S atom in the μ-κS:κS mode, while the monodeprotonated Hbimt− ligand bridges via S and N atoms in the μ-κS:κN1 mode.