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

The electrocatalytic water oxidation activity of three copper(II) complexes [Cu(L1H)(L)](ClO) (1), [Cu(L2H)(L)(HO)](ClO) (2) and [Cu(L3H)(L)](ClO) (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.