Synthesis, mesomorphic behaviour and optical anisotropy of some novel materials for nematic mixtures of high birefringence

Abstract

Structural moieties including core units (such as phenyl, naphthyl and thiophenyl), linking groups (such as ethynyl), terminal substituents (such as cyano, isothiocyanato and fluoro), and lateral fluoro substituents have been incorporated into novel materials designed to confer a high birefringence on nematic mixtures. The materials have all been prepared through convergent syntheses involving palladium-catalysed cross-coupling reactions of arylboronic acids. The materials were examined for their mesomorphic behaviour as neat materials and as mixtures; some materials were found to have extremely high nematic phase stability, and others were non-mesogenic. The materials were evaluated in nematic host mixtures for their optical anisotropy, and they were all found to show promisingly high values.