Kinetics and thermodynamics of formation and electron-transfer reactions of Cu-O 2 and Cu 2-O 2 complexes

Abstract

The kinetics and thermodynamics of formation of Cu(II)-superoxo (Cu-O 2) complexes by the reaction of Cu(I) complexes with dioxygen (O 2) and the reduction of Cu(II)-superoxo complexes to dinuclear Cu-peroxo complexes are discussed. In the former case, electron transfer from a Cu(I) complex to O 2 occurs concomitantly with binding of O 2 -to the corresponding Cu(II) species. This is defined as an inner-sphere Cu(II) ion-coupled electron transfer process. Electron transfer from another Cu(I) complex to preformed Cu(II)-superoxo complexes also occurs concomitantly with binding of the Cu(II)-peroxo species with the Cu(II) species to produce the dinuclear Cu-peroxo (Cu 2-O 2) complexes. The kinetics and thermodynamics of outer-sphere electron-transfer reduction of Cu 2-O 2 complexes are also been discussed in light of the Marcus theory of outer-sphere electron transfer. © 2012 Elsevier B.V..