Abstract
Rod-shaped mesogenic hydrazide (series I) derivatives have been synthesised by the Schotten-Baumann reaction of 4-chlorobenzhydrazide with 4-n-alkoxybenzoyl chloride using pyridine as a solvent. Rod-shaped mesogenic hydrazide (series I) have been cyclised to bent-shaped mesogenic oxadiazole (series II) and thiadiazole (series III) derivatives using POCl3 and P2S5, respectively. The synthesised compounds are characterised by a combination of elemental analysis and standard spectroscopic methods. All the compounds of present series I–III exhibit smectic A mesophase. The mesomorphic properties of the present series I–III are compared with each other and with the other structurally related mesogenic homologous series to evaluate the effect of bent-shape and different heterocyclic moiety on mesomorphism.
Acknowledgements
The authors thank the Dean, Faculty of Technology and Engineering, and Head, Applied Chemistry Department, for providing the research facilities.
Notes
This paper was presented at the 16th National Conference on Liquid Crystals (NCLC-2009) held at Department of Physics, University of Lucknow, Lucknow, 26–28 October 2009.