Behaviors of the One-Electron Reduction Species of {RuNO}6-Type Complexes. An Oxygen-Transfer Reaction Occurs in the Nitrosyl Site of cis-[Ru(NO·)X(bpy)2]n+ (X = ONO2 for n = 1, X = CH3CN, H2O for n = 2) ({RuNO}7-Type) to Give an Identical Nitro Species

Degradation sequences of cis-[Ru(NO·)X(bpy)2]n+ (X = ONO2, OCHO, OCOMe, NO2, Cl for n = 1; X = CH3CN, H2O for n = 2) ({RuNO}7-type), a one-electron reduction species of {RuNO}6-type complexes, were investigated in CH3CN by monitoring using electrochemical techniques (both cyclic and hydrodynamic voltammetries). The results show that an oxygen transfer occurs effectively at the nitrosyl site of cis-[Ru(NO·)X(bpy)2]n+ (X = ONO2 for n = 1, X = CH3CN, H2O for n = 2) to give identical nitro species, cis-[Ru(NO2)(CH3CN)(bpy)2]+. The extent that the nitrosyl-to-nitro conversion proceeded, however, differs depending on the X ligands; X = CH3CN and H2O complexes gave the nitro species in almost 40% yield, while X = ONO2 complex afforded nearly 80%. The monitoring results of the degradation sequences, along with the differences in yields, suggest that different processes are operating separately in the oxygen-transfer reaction. We propose some possible processes for both reactions, although a further investigation is needed for a detailed explanation.