Bifunctional decamethylcyclohexasilanes X2Si6Me10 (X = Cl,H, or OH): molecular and crystal structures and mesomorphic properties

Isomer separation of mixtures, which were prepared by chlorination followed by transformations of dodecamethylcyclohexasilane (Me₂Si)₆ into bifunctional decamethylcyclohexasilanes X₂Si₆Me₁₀ (X = Cl, H, or OH), was carried out. As a result, mixtures of the corresponding 1,3- and 1,4-derivatives were separated to obtain structural isomers, and stereoisomers, viz., cis- and trans-1,4-dihydrocyclohexasilanes, were isolated in individual form. The molecular and crystal structures of the resulting bifunctional decamethylcyclohexanes X₂Si₆Me₁₀ (X = H or OH) and decamethyl-7-oxahexasilanorbornane were established by X-ray diffraction analysis. Bifunctional cyclohexasilanes form a mesophase as a plastic crystal. The temperature range of its existence was determined. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1566–1575, July, 2005.