Electrochemical Reduction of CO2 Using Cu (II) and Ni (II) Complexes with 8-Hydroxyquinoline Ligand

Two dinuclear Cu (II) and Ni (II) complexes of the general formula [Cu2L2], (1), and [Ni2L6].4 (C2H5OH), (2), which L=8Hydroxyquinoline have been synthesized and characterized by elemental analysis, IR and UVVis spectroscopic methods. The crystal structure analysis showed the binuclear structure for 1 and the Cu (II) centers adopt a distorted square pyramidal geometries. Two Cu centers in complex 1 are linked via µO coordination bridge modes of 8hydroxyquinoline ligands with the CuCu distances of 3.534 Å. The electrochemical behavior of the free ligand and corresponding 1 and 2 complexes was studied in DMF. The cyclic voltammetry of the complexes 1 and 2 show an irreversible metal and ligand based reductions at negative potentials. The electrocatalytic activity of the complexes 1 and 2 was monitored for CO2 reduction in DMF solution. The results show that the complexes can be used as new electrocatalysts for CO2 reduction, leading to formation of carbon monoxide product.