摘要:
                                Photolysis of the 3 -methoxytrisilanyl comp lex CpM(CO)(2)SiMe2SiMe2SiMe2OMe (1a, M = Ru; Ib, M = Fe) afforded the intramolecularly methoxy-stabilized disilanyl-silylene complex Cp(OC)M(=SiMe2<--O(Me)SiMe2SiMe2) (2a, M = Ru; 2b, M = Fe) as a primary product. Prolonged irradiation of the solution resulted in the decay of 2a,b with release of a dimethylsilylene moiety to give the methoxy-bridged bis(silylene) complex Cp(OC)M(SiMe2... O(Me)... SiMe2) (3a, M = Ru; 3b, M = Fe). The X-ray crystal structure analysis of 2a revealed that 2a has a five-membered chelate ring and the Ru-Si(silylene) bond (2.291-(2) Angstrom) is much shorter than the other Ru-Si bond (2.350(1) Angstrom). It can be concluded from the bond lengths that the former possesses a partial double-bond character while the latter is a normal Ru-Si single bond. Photolysis of diisopropyl derivatives CpM(CO)(2)(SiMe2SiPr2)-Pr-i-SiMe2OMe (4a, M = Ru; 4b, M = Fe) gave Cp(OC)M(=SiMe2<--O(Me)(SiMe2SiPr2)-Pr-i) (5a, M = Ru; 5b, M = Fe) exclusively; in which the positions of substituents on silicon atoms in 5a and 5b were determined by Si-29-H-1 COLOC and NOESY NMR spectra. A mechanism involving 1,2-migration of the methoxydisilanyl group to the metal center was suggested. Irradiation of the tetrasilanyl complex CpFe(CO)(2)SiMe2SiMe2SiMe2SiMe2OMe (6) caused a complicated reaction, giving at least five products having methoxy groups coordinated to silylene ligands.