C—br insertion reactions in rhodium and iridium compounds containing an ortho-halo-arylphosphine. X-ray structures of two ortho-metallated compounds of formula IrX2[P(C6F4)Ph2][P(o-BrC6F4)Ph2], (X = Cl, Br)

Abstract A comparative study of the reaction of rh and ir complexes with the ortho-bromo-arylphosphine PCBr [PCBr = P(o-BrC6F4)(C6H5)2], is presented. Various PCBr complexes of Ir(I) and Rh(I) undergo rapid insertion of the metal atom into a CBr bond provided the phosphine is coordinated in a η2-mode (Pbr). If the Br coordination is substituted by a superior ligand such as CO or an olefin, no reaction occurs under normal conditions. PCBr complexes of the tervalent metals require a two-electron reduction step prior to the ortho-metallation reaction. Most intermediates were characterized by chemical and spectroscopic analysis. Two intermediates of general formula IrX2(η2-PC)(η-PCBr), [PC = …