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

Abstract

Two dinuclear Cu (II) and Ni (II) complexes of the general formula [Cu2L2], (1), and [Ni2L6].4 (C2H5OH), (2), which L=8-Hydroxyquinoline have been synthesized and characterized by elemental analysis, IR and UV-Vis 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 µ-O coordination bridge modes of 8-hydroxyquinoline ligands with the Cu-Cu 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.

Keywords

• copper (ii) complexes
• crystal structure
• electrocatalyst
• co2 reduction