Synthesis and Mesomorphic Properties of Schiff Base Esters Ortho-Hydroxy-Para-Alkyloxybenzylidene-Para-Substituted Anilines

A series of new compounds o-n-hydroxy-p-n-hexadecanoyloxybenzylideneaniline and its substituted derivatives was synthesized from the esterification of palmitic acid with intermediary Schiff bases, which posssess various terminal substituents X (X = H, F, Cl, Br, OCH3, CH3, and C2H5). All compounds possess mesomorphic properties wherein compounds with X = H, F, Cl, Br, and OCH3 exhibit smectic A (SmA) phases and those with terminal substituents CH3 and C2H5 are monotropic liquid crystals showing smectic C phases (SmC). Correlation studies of the clearing temperature (Tc) of the title compounds and polarizability related to mesophase stability and molecular anisotropy are reported.