Controlled reaction of molecular oxygen with [Mnl2(PPh2Me)2] to form the mixed phosphine–phosphine oxide complex [Mnl2(OPPh2Me)(PPh2Me)] and the Bis(phosphine oxide) complex [Mnl2(OPPh2Me)2]

Abstract

When a preformed solution of [Mnl₂(PPh₂Me)₂(O₂)] in pentane at –40 °C under argon was allowed to warm to room temperature, specific oxidation of one phosphine occurred and an almost quantitative yield of the mixed phosphine-phosphine oxide complex [Mnl₂(OPPh₂Me)(PPh₂Me)] was obtained; when the same procedure is followed under dry dioxygen the oxidation of both phosphines occurs and [Mnl₂(OPPh₂Me)₂] is obtained in almost quantative yield. X-Ray crystallography showed both of these complexes to be pseudo-tetrahedral monomers, and [Mnl₂(OPPh₂Me)(PPh₂Me)] represents the first example of a mixed phosphine–phosphine oxide complex of manganese to be reported.