| Abstract
| - A mixed-bridging bis(μ-silylene) complex, {Cp*Ru(μ-H)}2{μ-SiPh(OCOCF3)}(μ-SiPh2) (3b), containing a trifluoroacetoxy group on the bridging silicon atom was formed in the reaction of the bis(μ-diphenylsilyl) complex {Cp*Ru(μ-η2-HSiPh2)}2(μ-H)(H) (2a) with trifluoroacetic acid in toluene via an intermediate neutral μ-silyl,μ-silylene complex, (Cp*Ru)2(μ-η2-HSiPh2)(μ-SiPh2)(μ-CF3CO2)(μ-H)(H) (7), which underwent substitution reaction of the phenyl group to the trifluoroacetoxy group at ambient temperature.
- Treatment of a bis(μ-diphenylsilyl) complex, {Cp*Ru(μ-η2-HSiPh2)}2(μ-H)(H) (2a, Cp* =η5-C5Me5), with trifluoroacetic acid in toluene resulted in introduction of a trifluoroacetoxygroup on a bridging silicon atom with concomitant loss of one phenyl group as benzene,affording a mixed-bridging bis(μ-silylene) complex, {Cp*Ru(μ-H)}2{μ-SiPh(OCOCF3)}(μ-SiPh2)(3b), in moderate yield. Nucleophilic addition of the acetoxy group took place in theintermediate μ-silyl,μ-silylene complex (Cp*Ru)2(μ-η2-HSiPh2)(μ-SiPh2)(μ-CF3CO2)(μ-H)(H)(7), containing a bridging carboxylate group. The trifluoroacetoxy group of 3b underwentnucleophilic displacement at the bridging silicon atom, which afforded the mixed-bridgingbis(μ-silylene) complexes {Cp*Ru(μ-H)}2(μ-SiPhX)(μ-SiPh2) (3c, X = OMe; 3d, X = OH) upontreatment with methanol and aqueous KOH, respectively. VT NMR studies of 3b, 3c, 3d,{Cp*Ru(μ-H)}2(μ-SiPhMe)(μ-SiMe2) (3e), and {Cp*Ru(μ-H)(μ-SiPhMe)}2 (3f-syn) revealed alinear correlation between the electronic nature of the substituents on the bridging siliconatom and the activation parameters of the hydride site-exchange process occurring in thebis(μ-silylene) complex.
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