Study of the Effect of Chalconyl Central Bridge on Mesomorphism

A novel homologous series of chalconyl ester derivatives of thermotropic type of liquid crystals (LC) variety have been synthesized with its general molecular formula RO-C₆H₄-CH=CH-COO-C₆H₄-CO-CH=CH-C₆H₄-N(CH₃)₂ (Para). Present investigation is planned with a view to understand and establish the relation between molecular structure and the mesomorphic behaviorur of the constituent homologue derivatives as well as to avail novel mesomorphic (LC) substances to the researcher working on multidisciplinary thermotropic LC material with different aims, objects and views at different angles. Novel homologous series consists of twelve homologues C₁ to C₅ homologues are nonliquid crystals (NLC) and the rest of the C₆ to C₁₆ are monotropically nematogenic liquid crystals. Transition temperatures and texture of the LC and NLC were determined by an optical polarizing microscopy equipped with heating stage (POM). Textures of nematic phase are threaded or schlieren. Analytical and spectral data confirms the molecular structures of homologues. Thermal stability for monotropy is very low of the magnitudes of few second and of negligible degree of temperature difference. Thermal properties of present novel series are compared with of structurally similar series, data interpreted in terms of molecular rigidity and flexibility to derive group efficiency order.