Separation and identification of stereoisomers of a tetrameric side-chain liquid crystalline cyclic siloxane

Abstract

For the first time the four stereoisomers of a tetrameric side-chain liquid crystalline cyclic siloxane have been isolated in a pure state by high performance liquid chromatography. The structure of one of the stereoisomers was confirmed by ¹ H, ¹³ C and ²⁹ Si NMR. The structures of the remaining three stereoisomers were assigned by using evidence from the literature and their liquid crystalline thermal properties. All four stereoisomers and the isomeric mixture exhibited calamitic SmC and SmA phases; no discotic phases were found.