Synthesis, characterization and properties of a μ–η2:η2-carbonato-bridged bis(phosphinoferrocenyl) copper(I) complex from CO2 fixation

A μ–η2:η2-carbonato-bridged copper(I) dinuclear complex 3, of formula [Cu2(μ-CO3)(dppf)2]·[PhCONPh]·[Na(H2O)4]·CH2Cl2·2H2O (dppf = 1,1′-bis(diphenylphosphino)ferrocene) was synthesized and characterized by IR, 1HNMR and X-ray diffraction method. When chloride-bridged copper(I) complex reacted with N-phenyl benzamide with sodium methoxide as base under air or carbon dioxide atmosphere, the carbonate-bridged copper(I) complex from CO2 fixation was obtained. Cyclic voltammetry experiments of dppf ligand and complex 3 illustrate that the oxidation occurs only at the ferrocene(II) center, but complex 3 oxidizes at more negative potential than the uncoordinated dppf ligand. The thermal stability of complex 3 was also reported and discussed.