Electrochemical investigation of molecular oxygen interaction with iridium(I) complexes

The interaction between molecular oxygen and an iridium(I) chelate containing methyl-substituted phenanthroline and cyclooctadiene has been investigated by means of cyclic voltammetric and spectrophotometric techniques. Evidence is presented for the formation of an adduct, which decomposes irreversibly in solution leading to autoxidation, but gives rise to a kinetic reduction peak at a stationary mercury electrode. The very fast homogeneous reaction between the complex and the Superoxide anion is also discussed.