Reactions of silanes and germanes with iridium complexes. Part 4. Reactions with carbonylhydridotris(triphenylphosphine)iridium(I)

Abstract

The title complex, [IrH(CO)(PPh3)3](1), reacts with MH3Q (M = Si or Ge when Q = H, F, Cl, Br, or I; M = Si when Q = SiH3 or CH3) to give [IrH2(CO)(PPh3)2(MH2Q)]. The products have been characterised by 1H, 31P, and (where appropriate)19F n.m.r. spectra. Where M = Ge, the predominant isomer contains mutually trans phosphine ligands, whereas when M = Si the predominant (and in some cases the sole) product contains cis phosphines. In the isomers with cis phosphines, some unusual coupling patterns have been observed in the 1H n.m.r. spectra. When Q = I and M = Si, there is a difference in chemical shift between the two SiH protons of 1.3 p.p.m., and irradiation of one of the peaks at room temperature leads to the disappearance of the other, a phenomenon interpreted as due to saturation transfer; possible mechanisms for the process are discussed.