Kinetics and thermodynamics of formation and electron-transfer reactions of Cu-O_2 and Cu_2-O_2 complexes

摘要

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 (CU2-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.