Synthesis and liquid crystalline study of 2,4-bis (4¢-n-heptyloxybenzoyloxy) -benzylidene-4²-n¢-alkoxy aniline

The synthesis and study mesomorphic properties of a new series of 2,4-bis(4-nheptyloxybenzoyloxy)-benzylidene-4-n-alkoxy aniline (DC7A1-10) Have been reported. The structures of the prepared compounds were confirmed by FT-IR, H-NMR and elemental analysis (CHN). The mesomorphic properties were studied by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) measurements. All compounds of the series exhibited nematic (N) phases but the smectic phases are appear in (DC7A3-A10). The first two series (DC7A1, DC7A2) display only a nematic phases whereas the highest homologues (DC7A3A10) exhibit enanthiotropic dimorphism Nematic (N) and smectic (S) phases (the DC7A6 is only compound exhibit Sc and SA phases). The liquid crystalline behavior has been analyzed in terms of structural property relationship. The mesomorphic properties and thermal stabilities of the present series (DC7A1-10) were compared with those structurally related homologous series.