Eta3-silapropargyl/alkynylsilyl molybdenum complexes: synthesis, structure, and reactivity toward methanol.

Novel eta(3)-silapropargyl/alkynylsilyl complexes Cp*(CO)(2)Mo(eta(3)-Ph(2)SiCCR) (3a, R = (t)Bu; 3b, R = (i)Pr) were synthesized by the reactions of Cp*(CO)(2)(MeCN)MoMe (1) with alkynylsilanes HPh(2)SiC[triple bond]CR. The structures of 3a and 3b were fully characterized by NMR spectroscopy and X-ray crystallography. The reaction of 3a with MeOH at room temperature gave the stable four-membered metallacycle Cp*(CO)(2)MoC(=CH(t)Bu)SiPh(2)OMe (5a), while the corresponding reaction of 3b led to the formation of the eta(3)-allyl complex Cp*(CO)(2)Mo{eta(3)-(MeOPh(2)Si)HCCHCMe(2)} (7) via Cp*(CO)(2)MoC(=CH(i)Pr)SiPh(2)OMe (5b).