Reactions of copper(II) complexes of polydentate 8-mercapto-quinoline derivatives with phenols

Abstract The reactions of copper complexes with chelate thiaaza ligands as models of the active centres of ‘blue’ copper proteins have been studied. The overall reaction stoichiometry for the reduction of copper(II) complexes by 4-methyl-2,6-di-tert-butyIphenol as well as hydroquinone in acetonitrile was found to be 2:1. The reactions are first-order with respect to the concentration of both complex and phenol. The second-order rate constants and activation energies have been determined and the influence of ligand structure on these parameters discussed. The effect of pyridine in the reaction mixture on the redox potential and catalytic properties of some complexes on the oxidation of phenols by dioxygen was observed.