Reactions of Thienyl Containing Trisilane Under Irradiation

2-phenyl-2-furylhexamethyltrisilane and 2-phenyl-2-thienylhexamethyltrisilane (1) weresynthesized via Grignard-like reactions. The photolysis of 2-phenyl-2-furylhexamethyltrisilane inthe presence of 2,3-dimethyl-1,3-butadiene led to normal silylene-olefin addition and silylene C-Hinsertion reactions. Whereas, when 1 was photolyzed in the methanol-cyclohexene system, a radicalreaction mechanism is occurred. We suspect that the sulfur atom of the thienyl group strongly stabi-lized the silyl radical. This result was supported by both identifyling its typical radical reactions prod-ucts and ESR spectra of its quenching product with radical quencher.     

Aminoderivate hydrierter Oligosilane: Darstellung,Charakterisierung und Eigenschaften

Summary Amino derivatives of linear and branched tri- und tetrasilanes R₂N-H₂Si(SiH₂)SiH₂-NR₂ H₃SiSiHNR₂SiHNR₂SiH₃, R₂N-H₂SiSiH₂SiH₂SiH₂-NR₂ und (R₂N-H₂Si)₂SiHSiH(SiH₂-NR₂)₂ with R = Et, SiMe₃ are formed by the reaction of the corresponding bromooligosilanes with suitable amines or alkali metal amides. Product distribution and yields are strongly influenced by the nucleophilicity of the amino reagent and by the structure of the SiSi-backbone. The structures proposed for the aminopolysilanes thus prepared are proved by²⁹Si-,¹H-NMR-and MS-investigations.

     

Skeletal rearrangement of a bicylic 1,3-diphenyltrisilane during acid-induced dephenylation reactions

Protic and Lewis acid-induced dephenylation reactions of bis(tetramethylene)-tethered bicyclic 1,3-diphenyltrisilane 1 have been found to be accompanied by a facile skeletal rearrangement that forms the ring-contracted silyl-substituted bicyclic disilanes. For the reaction with a protic acid (HX), such as HCl/AlCl₃ and trifluoromethanesulfonic acid (TfOH), the protonation of the ipso-carbon of the phenyl group would be followed by the nucleophilic attack of X⁻ on the central silicon atom that induces the skeletal rearrangement. In the case of the reaction with boron trichloride, the same rearranged product was obtained as well, although the reaction mechanism is not clear. Dedicated to Professor Mitsuo Kira on the occasion of being awarded the 2005 Wacker Award and in recognition of his outstanding contribution to silicon chemistry.     

A facile route for the syntheses of trisilanes containing C-mono-substituted carborane

The syntheses of trislanes containing C-monosubstituted o-carborane are described.Hie intermediate compound,2-chloro-2-phenyl-hexamethyltrisilane,was prepared by elimination reaction between 2,2-diphenylhexamethyltrisilane and hydrogen chloride with a catalytic amount of aluminum chloride in chloroform solution.