Mesomorphism dependence on central bridge and tail ended polar group

Abstract

A novel azoester homologous series of laterally and terminally substituted viz, RO–C₆H₄–CH=CH–COO–C₆H₃–(CH₃) –N=N–C₆H₄–Cl is synthesized, characterized and studied with a view to understand and establish the relation between molecular structure and thermotropic liquid crystalline property of its homologs. Series consists of twelve homologs. LC properties commence from very first member of a series and continue up to last homolog as enantiotropic nematic with absence of smectic property even in the monotropic condition. Transition temperatures of homologs were determined by polarizing optical microscopy equipped with a heating stage. The transition curves Cr?N and N?I behaved in normal manner. Thermal stability for nematic is 196.7?C whose mesophaselength ranges from 35°C to 131°C.

Keywords:

• Azoester
• liquid crystal
• nematic
• smectic
• thermotropic

Acknowledgments

Authors acknowledge thanks to the Department of Chemistry (DST-FIST Funded & UGC-SAP Sponsored), Saurashtra University, Rajkot, for research work. Authors are also thankful to Dr. A.V. Doshi, Ex. Principal M.V.M. Science and Home Science College Rajkot, for his valuable co-operation during present investigation as and when needed. Also thanks to the National Facility for Drug Discovery through New Chemical Entities (NCE’s) for analysis of samples.