Arylalkane photo-oxidation under visible light and O2 catalyzed by molybdenum(VI)dioxo-dibromo (4,4′-dicarboxylato-2,2′-bipyridine) anchored on TiO2

Abstract The molybdenum(VI)dioxo-dibromo compound bearing a carboxylate substituted bipyridyl ligand was anchored covalently onto a TiO 2 matrix (DG-25). It was fully characterized by IR(KBr), UV-diffuse reflectance, IR-photoacoustic (FT-IR/PAS) and solid state 13 C NMR spectroscopies. Its reactivity as an O-atom transfer agent was tested under visible light irradiation on ethylbenzene and tetraline, stoichiometrically under N 2 and catalytically under O 2 and then compared with the analogous homogeneous complex bearing a carbomethoxy substituted bipyridine. An important synergic effect was observed, attributed to the photogenerated electron flux, via TiO 2 , onto the coordination sphere of molybdenum. The anchored system, furthermore, prevented any deactivation of the reactive center, as it is observed in the homogeneous medium, through the formation of a μ-oxo species.