Syntheses and Reactivites with Olefins of Ruthenium(￥3) Oxo/Ruthenium(￥±)-Aqua Complexes that Contain 2,6-Bis(N-pyrazolylpyridine)

摘要

The syntheses and reactivities with olefins of [Ruケ(L3)(L2)OH2]2+ [L3= 2,6-bis(N-pyrazolyl)pyridine(bpp), 2,6-bis(3,5-dimethyl-N-pyrazolyl)pyridine (Me4bpp); L2= 2,2`-bipyridine(bpy), 4,4`-dimethyl-2,2`-bipyridine (Me2bpy)] are described. Their spectral and redox properties in aqueous solution were investigated. Evidence for each one electron redox process for the Ruコ-Ruゲ and Ruゲ-Ruケ couples has been obtained. Oxidation of [Ruケ(bpp)(bpy)OH2]2+ with Ceコ gave[Ruコ(bpp)(bpy)O]2+. The Ruコ= 0 complex is paramagnetic (レeff = 2.82) and the complexes [Ru(L3)(L2)OH2]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.