“Dependence of Mesomorphism in Combination with Fluoro and Chloro Groups”

Abstract

A novel azoester homologous series with chloro lateral group and a fluoro terminal end group was synthesized and characterized for mesomorphic properties. It consists of thirteen azo ester derivatives from trans-4-n-alkoxy cinnamic acid with 4-hydroxy-3-chloro phenyl azo-3-chloro-4-fluoro benzene. Mesomorphic property commences from C4homologue as smectic.C1 to C3 member of the series are non-mesomorphic. C4 to C18 homologous are enantiotropic smectic A phase. The nematic mesophase is totally absent. Texture and transition temperatures of the homologues are determined by an optical polarizing microscopy equipped with heating stage. 1H NMR, IR spectra, mass spectra, of some member is included. The spectroscopic analysis supports the molecular structure. A phase diagram is used to illustrate the mesomorphic behaviour across the series. Mesophaselength for smectic is varying from18.0°C to 69.00C. Mesomorphic properties of the novel azoester series are compared with structurally similar series.