Bis(diphenylphosphino)ferrocene as an intramolecular bridging ligand in N-functionally substituted 1,3-azapropanedithiolate diiron complexes: synthesis and catalysis of proton reduction

Reaction of 1,1′-bis(diphenylphosphino)ferrocene (dppf) with [μ-(SCH₂)₂NCH₂CH₂OH]Fe₂(CO)₆ (A) or [μ-(SCH₂)₂NCH₂CH₂SAc]Fe₂(CO)₆ (C) in refluxing xylene yielded an intramolecular bridging complex [μ-(SCH₂)₂NCH₂CH₂OH]Fe₂(CO)₄(μ-dppf) (1) or [μ-(SCH₂)₂NCH₂CH₂SAc]Fe₂(CO)₄(μ-dppf) (2) in moderate yield. The structures of both complexes were fully characterized by spectroscopic methods and X-ray crystallography, and the electronic structure of 2 was further investigated by UV–vis. The cyclic voltammetry was conducted and the reduction of protons from CF₃SO₃H (TfOH), HBF₄·Et₂O, or CF₃COOH (TFA) catalyzed by 2 was observed.