Conformational analysis and simulation of the structures of diisobutylsilanediol and dihydroxytetraalkyldisiloxanes and their analogs [R2(HO)Si]2X (X = CH2, S), precursors of liquid-crystalline phases

Molecular mechanics studies of structure formation in condensed phases of R₂(HO)Si]₂X (X = CH₂ (dihydroxydicarbosilanes) and X = S (dihydroxydisilthians)) compounds have been performed and the results have been compared with those obtained for previously known columnar mesophases of R₂(HO)Si]₂O (R = Et and Pr) (dihydroxydisiloxanes). Conformational analysis demonstrates the similarity in structure and cross-linking of dihydroxydisiloxanes and dihydroxydicarbosilanes and the difference between these compounds and dihydroxydisilthians. This allows the conclusion that for dihydroxydicarbosilanes the columnar mesophase formed by H-associates can occur. Simulation of dimeric and trimeric H-associates for (Buⁱ)₂Si(OH)₂, which belong to the same class of mesophases, has been performed.Deceased in August, 1995.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1711–1715, September, 1995.This work is supported by the International Science Foundation (Grant MP5 000).