New chiral smectic C materials. Introduction of chirality in SCphases by means of mixtures

Three new series of derivatives of benzalazines have been synthesized and the mesomorphism has been studied. Most of the compounds exhibit mesogenic properties. The S-4′-alkoxy-2,2′-dihydroxy-4-(2-methyl-butoxy)benzalazines show cholesteric (Ch) and chiral smectic C (S′C*) phases. The S-4′-alkoxy-2,2′-dihydroxy-4-(2-methylbutoxy)-α,α′-dimethylbenzalazines and the S-4′-alkoxy-2-hydroxy-4-(2-methylbutoxy)-α,α′-dimethylbenzalazines show cholesteric and smectic A (SA) phases. Mixtures of the latter compounds with compounds of similar structure that exhibit an achiral smectic C phase have been made, and their mesomorphism studied. The mixtures show chiral smectic C phases in wide temperature ranges.