H-D kinetic isotope effects of 16 and 22 in the oxidation of H/sub 2/O/sub 2/

Mechanisms are suggested for the oxidation of H/sub 2/O/sub 2/ by both (bpy)/sub 2/(py)Ru/sup IV/O/sup 2 +/ and (bpy)/sub 2/(py)Ru/sup III/OH/sub 2//sup 2 +/ over the pH range 2 to 10. Stopped-flow or simple mixing techniques were used to obtain rate constants for two reaction pathways. It was demonstrated that the Ru(IV) reactions, which could proceed via one- or two-electron steps, involves initially one-electron steps as do the oxidations involving Ru(III). Isotope effect studies using D/sub 2/O as a solvent yielded striking observation that the reactions of acid-independent pathways show the existence of H-D isotope effects of considerable magnitude. Isotope effect data for the inverse acid path support the earlier idea of the importance of proton content in the determination of the redox mechanism. (BLM)