Effect of ligand substituents on the reactivity pathways of copper(ii) complexes towards electrocatalytic water oxidation

Abstract

The electrocatalytic water oxidation activity of three copper(II) complexes [Cu(L₁H)(L₁)](ClO₄) (1), [Cu(L₂H)(L₂)(H₂O)](ClO₄) (2) and [Cu(L₃H)(L₂)](ClO₄) (3) with aryl oxime ligands L₁H, L₂H and L₃H [L₁H = 1-(pyridin-2-yl)methanone oxime, L₂H = 1-(pyridin-2-yl)ethanone oxime and L₃H = 1-(pyridin-2-yl)propanone oxime] was investigated. All the three ligands have in common a pyridyl group attached to the carbon centre of the oxime moiety and differ in the second substituent attached to the carbon centre. Electrochemical investigation of the catalytic activity of complexes 1, 2 and 3 shows that the nature of the substituent attached to the carbon centre has an influence on the catalytic pathway and overall catalytic activity of these complexes.