Solvent and pH effects on the redox behavior and catecholase activity of a dicopper complex with distant metal centers

A dicopper complex is described for which significant catecholase activity was found, particularly for a compound in which the two metal ions are more than 7 Å apart. Variations on the catecholase activity of this complex were explored in a range of pH values from 5.5 to 9.0 in two solvent mixtures, MeCN/H2O and MeOH/H2O. The catalytic performance of the complex was found to be substantially better in the second, where the maximum activity was achieved at a pH value one unit lower than in the first. Electrochemical studies of the complex in the absence and presence of dioxygen revealed a very different behavior in each of the two solvent mixtures, which may account for the correspondingly distinct catalytic activity.

Electrochemical studies may account for the different catecholase activities of a dicopper complex in MeOH/H2O and in MeCN/H2O.Figure optionsDownload as PowerPoint slide