Synthesis of dirhenium species with benzamidate ligands via hydrolysis of benzonitrile†

Abstract

Benzonitrile co-ordinated to a metal–metal bonded dirhenium core has been shown to undergo hydrolysis in ethanol solvent systems to form benzamidate and remains co-ordinated to the dirhenium core as a bridging ligand. The compounds [NBu₄][Re₂Cl₆{µ-PhC(O)NH}]·0.5CH₂Cl₂ 1 and [Re₂Cl₄(µ-dppm)₂{µ-PhC(O)NH}] 2, where dppm is bis(diphenylphosphino)methane, were synthesized from the reaction of [NBu₄]₂[Re₂Cl₈] in an ethanol solvent system with benzonitrile containing 3% water. While compound 1 is the hydrolysis product of the reaction of [NBu₄]₂[Re₂Cl₈] with benzonitrile, 2 arises from the reduction of 1 upon co-ordination of the bidentate phosphine ligand dppm. The structures of 1 and 2 were determined by X-ray crystallography and the compounds characterized by a variety of spectroscopic methods.