Rhodium Complexes in P–C Bond Formation: Key Role of a Hydrido Ligand

Olefin hydrophosphanation is an attractive route for the atom-economical synthesis of functionalized phosphanes. This reaction involves the formation of P–C and H–C bonds. Thus, complexes that contain both hydrido and phosphanido functionalities are of great interest for the development of effective and fast catalysts. Herein, we showcase the excellent activity of one of them, [Rh­(Tp)­H­(PMe3)­(PPh2)] (1), in the hydrophosphanation of a wide range of olefins. In addition to the required nucleophilicity of the phosphanido moiety to accomplish the P–C bond formation, the key role of the hydride ligand in 1 has been disclosed by both experimental results and DFT calculations. An additional Rh–H···C stabilization in some intermediates or transition states favors the hydrogen transfer reaction from rhodium to carbon to form the H–C bond. Further support for our proposal arises from the poor activity exhibited by the related chloride complex [Rh­(Tp)­Cl­(PMe3)­(PPh2)] as well as from stoichiometric and kinetic studies.