ABSTRACT
A novel homologous series of liquid crystals (LC) 4-(4′-n-alkoxy cinnamoyloxy)-4′′-bromobenzylbenzoate was synthesized and studied with a view to understanding and establishing the relation between LC properties and the molecular structure. The novel series comprises 11 members, and all the members exhibit mesomorphism as enantiotropic smectic. None of the homologues are nematogenic, even in the monotropic condition. Transition temperatures were determined by an optical polarizing microscope equipped with a heating stage. The textures of smectic phase are of the type A or C. The transition curves Sm-I and Cr-Sm behave in a normal manner in the phase diagram. An odd-even effect is exhibited by the Sm-I transition curve. Thermal stability for smectic is 102.6°C. Mesomorphism commences from the very first member of the series. The series is entirely smectogenic and of middle-order melting type whose mesomorphic phase length ranges from 7.4°C to 60.9°. Analytical and spectral data confirmed the molecular structures of homologues. The mesomorphic properties of the present series are compared with structurally similar homologous series.
Acknowledgments
Authors acknowledge thanks to the Green Circle Inc. Laboratory for providing research facilities and services as and when needed. Authors acknowledge thanks to the Baldev Prajapati (Rajesh Pharma, Ankleshwar) for providing research chemicals (4-Bromobenzyl alcohol/bromide). Authors are also thankful to Drs. N. N. Vyas, Vipul Patel, and M. L. Chauhan, P. T. Arts and Science College, Godhara, for their valuable helping hand and microscopic facility. Also thanks are due to the Sophisticated Analytical Instrumentation Facility, Punjab University, Chandigarh, for extending their help for analytical services.