Mesomorphic Behavior of Chloro Substituted Azoesters. A Novel Homologous Series, 4-(4′-n-Alkoxy Benzoyloxy) Phenyl Azo-3^″,4^″-dichlorobenzenes

Abstract

The titled novel homologous series consists of 12 members. Mesomorphic behavior as a nematic phase commences from the first member of the series to the hexadecyloxy homologue. The smectogenic mesophase commences from the hexyloxy homologue to the hexadecyloxy homologue with nematogenic mesophase formation in an enantiotropic manner. The textures of the nematic phase are Schileren or threaded and those of the smectic phase are focal conic fan shaped. Analytical and spectral data matched with the molecular structure of the homologues. A phase diagram shows the phase behavior, and consists of solid-mesomorphic, nematic–isotropic, smectic-nematic transition curves that behave in a normal manner with the exhibition of an odd–even effect. The thermal stabilities for smectic and nematic are 106.0°C and 156.8°C respectively. Smectogenic and nematogenic mesophase temperature ranges vary from 07°C to 24°C, 26°C to 88°C respectively. Isotropic transition temperatures vary between 110°C and 205°C. Thus, the present novel series is predominantly nematogenic and partly smectogenic whose mesomorphic behavior ranges from 34°C to 88°C. Thus, it is middle ordered melting type series.

Keywords:

• Enantiotropy
• liquid crystals
• mesomorphism
• nematic
• smectic

Acknowledgment

Authors acknowledge thanks to the head, applied chemistry faculty of technology, The M.S. University of Baroda, Vadodara. Thanks are due to the CSMCRI-Bhavnagar for their analytical and spectral services.