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 [-(SCH2)(2)NCH2CH2OH]Fe-2(CO)(6) (A) or [-(SCH2)(2)NCH2CH2SAc]Fe-2(CO)(6) (C) in refluxing xylene yielded an intramolecular bridging complex [-(SCH2)(2)NCH2CH2OH]Fe-2(CO)(4)(-dppf) (1) or [-(SCH2)(2)NCH2CH2SAc]Fe-2(CO)(4)(-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), HBF4Et2O, or CF3COOH (TFA) catalyzed by 2 was observed.