Syntheses and reactions of metal carbonyl complexes containing the trimethylsilylmethyl ligand; CO insertion reactions assisted by the trimethylsilylmethyl groups

Abstract

Trimethylsilylmethyl complexes of ruthenium and tungsten, Cp(CO),RuCH2SiMe3 (1) (Cp = η5-C5H5) and Cp(CO)3WCH2SiMe3 (2) were prepared by reactions of ClMgCH2SiMe3 with CP(CO)2RuCl and Cp(CO)3 WCl respectively, in ether at low temperature. The complex (CO)5ReCH2SiMe3 (3) was prepared by reaction of ICH2SiMe3 with NaRe(CO)5 in THF. In contrast to the severe conditions required for the CO insertion reactions of Cp(CO)2RuCH3 and Cp(CO)3WCH3, carbonylation reactions of 1 and 2 with PPh3 took place readily under mild conditions and gave two acyl complexes Cp(CO)3(PPh3)RuC(O)CH3 (4) and Cp(CO),(PPh3)WC(O)CH3 (5) respectively. The reaction of 3 with PPh3 in CD3CN retained the trimethylsilyl group and gave both the acyl product (CO)4(PPh3)ReC(O)CH2SiMe3 (6) and the substitution product (CO)4(PPh3)ReCH2SiMe3 (7). The CO insertion reactions of these three complexes are believed to be assisted by the MCSi angles being rather larger. The RuCSi angle of 1 is 119°.Complexes 1 and 5 · 1.5C6H6 were confirmed by X-ray crystallography: Crystal data for 1: space group P1, a = 6.933(1)°, b = 8.455(1) Å, c = 12.001(1) Å, α = 105.88(1)°, β = 98.41(1)°, γ = 92.55(1) °, V = 666.7 Å3, Z = 2; R(F) = 0.0296, Rw(F) = 0.0254, based on 4586 reflections with I > 3σ(I). Crystal data for 5: space group P1, a = 8.922 (2) Å, b = 13.496(2) Å, c = 13.925(2) Å, α = 102.94(1)°, β = 109.71(2)°, γ = 87.13(1)°, V = 1537.9 Å3, Z = 2; R(F) = 0.0253, Rw(F) = 0.0190, based on 4596 reflections with I > 3σ(I). The other complexes were characterized by spectroscopic studies.