Abstract
Chalconyl homologous series: RO-C6H4-COO-C6H4(m)-CO-CH=CH-OC14H29(n) para has been synthesized and studied with a view to establish the relation between the molecular structure and thermotropic Liquid crystalline (LC) properties. Novel nonlinear series consists of thirteen members (C1 to C18) of a series. C6 to C18 members are enantiotropically nematogenic and the rest of the homologues ( C1 to C5 ) are nonliquid crystals (NLC). Smectogenic character is totally absent. Transition temperatures and the textures of the novel homologues were determined by an optical polarizing microscopy (POM) equipped with a heating stage. Textures of a nematic phase are threaded or schlieren. Transition curves Cr-N/I and N-I behaved in normal manner. N-I transition curve exhibited odd-even effect. Analytical and spectral data confirmed the molecular structures of homologues. Thermal stability is 107.0 and mesomorphic nematogenic degree of mesomorphism vary minimum to maximum are 17.0°C to 35.0°C at the C14 and C8 homologues respectively. Some mesogenic properties of presently investigated homologous series are compared with structurally similar isomeric and nonisomeric homologous series, and their group efficiency order derived. Thus, present novel series is nematogenic with absence of smectogenic character whose nematogenic transition temperatures vary from 74.0°C to 117.0°C.
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