Synthesis, characterization and properties of copper(I) complexes with bis(diphenylphosphino)-ferrocene ancillary ligand

Three copper(I) complexes (2–4) containing dppf ancillary ligand (dppf = bis(diphenylphosphino)-ferrocene) were synthesized when chloride-bridged copper(I) complex 1 reacted with acetanilide and characterized by IR, element analysis and NMR spectrum. And the crystal structures of complexes 2 and 4 have been determined by X-ray diffraction method. Complex 2, an acetate-bridged copper(I) complex, was obtained under N2 atmosphere in un-dried solvent; the acetate ion came from the hydrolysis reaction of acetanilide due to residual water in solvent. Acetanilide was deprotonated and coordinated with the copper(I) centre to form a copper(I) amidate complex 3 when reacted in pre-dried solvent. In addition, a known complex 4, the oxidation product of dppf, was isolated from the same reaction system when reacted in air atmosphere. CV and TG experiments were carried out to check the electron transfer properties and thermal stabilities of complexes 2–3. Finally, the arylation reaction of complex 3 with iodobenzene was performed to study the reaction mechanism of copper(I) catalyzed Goldberg reaction.

► Various products were obtained for the same reactants under different conditions.
► Acetate-bridged copper(I) complex 2 was obtained in undried solvent in N2 media.
► Copper(I) amide complex 3 was prepared in dried solvent in N2 media.
► Oxidation product of dppf was obtained in undried solvent in air media.
► Thermal and electrochemical properties of 2–3 and arylation reaction of 3 were determined.