Electrochemistry of copper(II) complexes of dioxocyclam and dihydroxamate derivative

The copper complexes with a dihydroxamate derivative of dioxocyclam (DOCYDMAHA) and the backbone macrocycle dioxocyclam (DOCY) have been investigated in aqueous solution by cyclic voltammetry (CV) to determine the mechanism involved in the electron transfer processes. This study shows that whereas the reduction of the parent macrocycle DOCY proceeds via one two-electron step [Cu(II)/ Cui(0)] with irreversible behavior, the reduction of the corresponding dihydroxamate derivative occurs via two one-electron steps [Cu(II)/Cu(I) and Cu(I)/Cu(0)] with reversible/quasireversible mechanisms. The equilibrium constants for the formation of the Cu(I)-DOCYDMAHA complex have been determined by CV Conclusions about the stability of this Cu(I) species are drawn based on the role of the hydroxamate substituents on the copper center in the comparison with the behavior of some analogs.