Liquid-crystalline compounds with lateral aromatic branches

Abstract
We present the synthesis of 2-substituted hydroquinone-bisbenzoates which have large 2-substituents containing aromatic and other ring systems. Contrary to the general accepted opinion these large lateral substituents which cause remarkable deviations from the rod-like shape of the molecules do not prevent the liquid-crystalline properties, the compounds are nematic and smectic. The influence of different chemical groups on the liquid-crystalline properties is investigated systematically. The compounds tend to exhibit the glassy nematic state above room temperature. This property may be used for the construction of thermo-electrooptic devices.