Amine-oxide-mediated oxidative methanolysis of metal-metal bonds in [MM'(CO)10] (M = Mn, Re; M' = Re) and [Os3(CO)12]: Crystal structure of fac-[Re{OC(O)OMe}(CO)3(η2-dppf)]

Abstract

The reaction of 1,1'-bis(diphenylphosphino)ferrocene (dppf) with a mixture of [MnRe(CO)10], MeOH and Me3NO afforded the complexes fac-[MnH(CO)3(η2-dppf)] and [Re2(μ-OMe)2(μ-dppf) (CO)6]. In the one-pot reaction of [Re2(CO)10] with Me3NO, MeOH and dppf, the major mononuclear Re species isolated was the CO2-inserted complex fac-[Re{OC(O)OMe}(CO)3(η2-dppf)], the crystal structure of which was determined. The coordination sphere of the rhenium atom is roughly octahedral, consisting of an oxygen atom from the methyl carbonate ligand, two phosphorus atoms from a chelating dppf ligand, and three carbon atoms from a facial arrangement of three terminally bonded carbonyls. Analogous Me3NO-mediated methoxylation reactions involving [Os3(CO)12] were also investigated. With a [Me3NO]:[Os3(CO)12] ratio of 2:1, the major product is [Os3(CO)10(μ-H)(μ-Ome)]. With three molar equivalents of Me3NO, significant quantities of [Os3(CO)10(μ-OMe)2] are also obtained. (C) 2000 Elsevier Science Ltd.