Iridium Dioxygen Complexes in the Oxidation of Substrates: Kinetics, Mechanism, and Steric and Electronic Effects in the Oxidation of CO, CO2, PPh3, and SO2 by RIr(O2)(CO)L2 (R = Me, Ph, Np; L = PPh3, P(p-tolyl)3, PPh2Me, P(p-C6H4OMe)3)

Article abstract of DOI:10.1021/ja00198a037

The preparation, characterization, and oxygen-transfer reactivity of the iridium dioxygen complexes RIr(O2)(CO)L2 (R = Me, Ph, Np; L = PPh3, P(p-tolyl)3, PPh2Me, PMe2Ph, and P(p-C6H4OMe)3) are reported.These complexes oxidize carbon monoxide to carbonate, sulfur dioxide to sulfate, carbon dioxide to peroxycarbonate, and triphenylphosphine to triphenylphosphine oxide but are relatively inert to other possible substrates.The kinetics of the oxidations of CO and CO2 are reported and indicate a mechanism of reversible conversion of the dioxygen from bidentate to monodentate followed by reaction with free substrate in solution.The phosphine ligand dependence on the rate of CO oxidation indicates that more electron density slightly increases the rate of oxygen transfer and that steric interactions impede the rate.