Addition reactions of tris(triphenylphosphine)chlororhodium(I); hydrido-, alkyl, and acyl complexes; carbon monoxide insertion and decarbonylation reactions

Abstract

Solutions of tris(triphenylphosphine)chlororhodium(I), RhCl(PPh₃)₃, interact with hydrogen chloride to give the hydrido-complex, RhCl₂H(PPh₃)₂, which is characterised by nuclear magnetic resonance (n.m.r.) and other studies. This complex reacts readily in solution at low temperatures with ethylene, tetrafluoroethylene, and acetylene to give the complexes RhCl₂(R)(PPh₃)₂, R = Et, C₂F₄H, and C₂H₃. The ethyl and vinyl complexes undergo ready insertion reactions with carbon monoxide to give the corresponding acyl derivatives. Acyl and aroyl complexes have also been prepared by direct addition of the halide, RCOCl, to RhCl(PPh₃)₃ in solution. The natures of the intermediates in these “insertion” reactions and of the mechanisms of the decarbonylation of acyl compounds and also of aldehydes are discussed.