Liquid Crystalline Properties of Unsymmetrical N-(o-hydroxybenzylidene)- N'-(4-n-alkoxybenzoyloxybenzylidene)azines: Synthesis and Characterization

摘要

A new series of mesogenic unsymmetrical azines, N-(o-hydroxybenzylidene)-N'-(4-n-alkoxybenzoyloxybenzylidene)azines, HOC_6H_4CH=N-N=CHC_6H_4OCOC_6H_40 C_mH_(2m+1) (m= 7, 8, 9, 10, 11, 12, 14, and 16) have been prepared. They have been characterized by elemental analyses, FT-IR, UV-visible, ~1H, and ~(13)C NMR (Nuclear Magnetic Resonance) spectra. The mesomorphic properties of these compounds were investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The azines m=7, 10, and 14 exhibit features of enantio tropic nematic (N) mesophase whereas azines m = 8, 11 exhibit features of a monotropic nematic phase. The azines m = 9, 12, and 16 do not exhibit mesogenic nature.