Study of Mesomorphism Changing on Terminal Side Chain with Different Thioalkyl Group

A novel mesomorphic series is RS-C₆H₄-COO-C₆H₄-CO-CH=CH-C₆H₄-OC₁₈H₃₇(n) (para) of chalconyl ester play double role thermotropic as well as lyotropically bioactive is synthesized and studied with a view to understand and establish the effect on mesomorphism when changing on left thioalkyl chain.the relation between mesomorphism and molecular structure on the basis of molecular rigidity and flex Novel series consists of thirteen homologues of which four homologues (C₁ to C₃) are non liquid crystal and the rest of the homologues (C₅ to C₁₈) are thermotropically enantiotropic nematic absences with smectic property. Thermometric transition temperatures and textures of nematogenic phase are determined by an optical polarizing microscopy equipped with a heating stage (POM).Textures of nematicphas schilieren and threaded type. Cr-N/I and N-I transition curves behaves in as manner with negligible abnormality at C₁₈ homologue in phase diagram of a series.Analytical and spectral data conforms the molecular structure of homologues. Thermal stability for nematic is 123.2 °C whose degree of mesomorphism vary minimum from 4.0°C to a maximum of 24.0 °C, and hence novel series is of middle ordered melting type.