Abstract
The syntheses and reactivities with olefins of $[Ru^{II}(L_3)(L_2)OH_2]^{2+}$ $[L_3$= 2,6-bis(N-pyrazolyl)pyridine(bpp), 2,6-bis(3,5-dimethyl-N-pyrazolyl)pyridine $(Me_4bpp);\;L_2$= 2,2'-bipyridine(bpy), 4,4'-dimethyl-2,2'-bipyridine $(Me_2bpy)$] are described. Their spectral and redox properties in aqueous solution were investigated. Evidence for each one electron redox process for the $Ru^{IV}-Ru^{III}$ and $Ru^{III}-Ru^{II}$ couples has been obtained. Oxidation of $[Ru^{II}(bpp)(bpy)OH_2]^{2+}$ with $Ce^{IV}$ gave $[Ru^{IV}(bpp)(bpy)O]^{2+}$. The $[Ru^{IV}$= 0 complex is paramagnetic $({\mu}_{eff}=2.82)$ and the complexes $[Ru(L_3)(L_2)OH_2]^{2+}$ are robust catalysts for the oxidation of styrene, cyclohexene, and cyclooctene with cooxidant such as NaOCl. Product distributions and selectivities are discussed by varying the number of the substituted-methyl group in the ring.