Mesomorphic Characteristics of Some New Homologous Series with the Isothiocyanato Terminal Group

Abstract

The synthesis is described and the mesomorphic properties have been tested for two homologous series of compounds with the isothiocyanato (-NCS) terminal group: 4-(trans-4′-n-alkylcyclohexyl)isothiocyanatobenzenes (CHBT—formula 1) and 5-trans-n-alkyl-2-(4′-isothiocyanatophenyl)-1,3-dioxans (DBT—formula 2). CHBT are nematics, and reveal low viscosity and low melting points, DBT are A₁ smectics. In this work, binary phase diagrams are presented for mixtures of CHBT or DBT with compounds with the —CN terminal group. CHBT and DBT yield with the latter simple eutectics. Moreover, DBT when mixed with A _d smectics at an appropriate smectic layer spacing ratio, yield nematic mixtures. The suitability of CHBT as components of display mixtures is postulated.