DYNAMICAL INVESTIGATIONS OF THE CATALYTIC MECHANISMS OF WATER OXIDATION BY THE [(BPY)(2)RU(OH2)]2O(4+) ION

Steady-state kinetic methods have been applied to the study of xo)bis[ cis-aquabis(2,2'-bipyridine)ruthenium(III)] ion-catalyzed water oxidat ion by the Co3+ ion. Initial rates of O-2 evolution exhibited first-or der dependence upon the catalyst concentration, indicating that the ca talytic cycle involves a single mu-oxo ion. The rate dependence upon C o3+ and Co2+ concentrations was complex, but consistent only with dime ric ions in the Ru2O [5,5] or higher oxidation states being the O-2-re leasing species. These data are consistent with our previously propose d mechanistic model in which a significant component of catalysis is a ctivation of solvent water by hydrogen bonding to the bridging mu-oxo atom.