title: Hydrido(hydrosilylene)tungsten complexes: dynamic behavior and reactivity toward acetone.
abstract: Reaction of a labile tungsten nitrile complex, [(Cp*)W(CO)(2)(NCMe)Me] (Cp*=η(5)-C(5)Me(5)), with H(3)SiC(SiMe(3))(3) gave the hydrido(hydrosilylene) complex [(Cp*)(CO)(2)(H)W=Si(H){C(SiMe(3))(3)}] (1a). The hydrido(silylene) complex [(η(5)-C(5)Me(4)Et)(CO)(2)(H)W=SiMes(2)] (2) (Mes=2,4,6-Me-C(6)H(2)) was synthesized by a similar reaction with H(2)SiMes(2). There is a strong interligand interaction between the hydrido and silylene ligands of these complexes; this was confirmed by a neutron diffraction study of [D(2)]1b, that is, the deuterido and η(5)-C(5)Me(4)Et derivative of 1a. The exchange between the W-H and the Si-D groups was observed in the deuterido complex [D]1a. This H/D exchange proceeded slowly at room temperature, but very rapidly under UV irradiation. Variable-temperature NMR spectroscopy measurements show the dynamic behavior of carbonyl ligands in 1a. Complex 1a reacted with acetone at room temperature to give mainly a hydrosilylation product, [(Cp*)(CO)(2)(H)W=Si(OiPr){C(SiMe(3))(3)}] (3a), along with a siloxy complex, [(Cp*)(CO)(2)WO(Si(H)iPr{C(SiMe(3))(3)})] (4a). At low temperature, a different reaction, namely, α-H abstraction, proceeded to give an equilibrium mixture of 1a and a dihydrido(silyl) complex, [(Cp*)(CO)(2)(H)(2)W(Si(H){OC(=CH(2))Me}{C(SiMe(3))(3)})] (5).
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan.
authors.forename: Takahito
authors.initials: T
authors.lastname: Watanabe
authors.forename: Hisako
authors.initials: H
authors.lastname: Hashimoto
authors.forename: Hiromi
authors.initials: H
authors.lastname: Tobita