Synthesis and mesomorphic properties of 4-(4-bromopropyloxy)-4′-(4-alkyloxybenzylidene)anilines

This article describes the preparation and liquid crystalline properties of a new homologous series of 4-(4-bromopropyloxy)-4′-(4-alkyloxybenzylidene)anilines in which the phenyl ring is armed by a bromopropyloxy chain. The thermal behavior and mesomorphic properties of the synthesized compounds were studied with particular attention given to the correlation between their phase transition temperatures and anisotropic change influenced by molecular structure. All the members displayed enantiotropic smectic phase except for the homologue with the longest alkyloxy chain (R = C18H37), exhibiting only monotropic characteristic. The presence of bromine atom from the propyloxy side chain is found to be capable of altering and influencing the mesomorphic properties.