Hydrogen Bonded Thermotropic Liquid Crystalline Properties of some New Schiff Basses

Abstract

A new homologous series of Schiff bases ester,2-hydroxybenzylidineanilines:N-[4-(4^,-n-(alkoxybenzoyloxy)-2-hydroxybenzylidine]-4^,,-carboxyanilines   ( HAHC ) were    (n=1-10) synthesized and characterized by spectroscopic techniques (IR and ¹HNMR) and microelemental analysis. Mesomorphic behavior and phase transitions were studied using polarized hot stage optical microscopy (POM) and differential scanning calorimetry (DSC). It has been found that the compounds with(C?-C?) of the series exhibit enantiotropic nematic phase only while those compounds with  (C?-C?) show smectic C in addition to nematic phase. While compounds with (C?-C??) show smectic C phase only.

Key words: Schiff Basses Liquid crystals , Thermotropic liquid crystals, Nematic phase , Synthesis of Liquid Crystalline compounds , Smectic C phase , Hydrogen bonded liquid crystals phases