Abstract
Azoester novel homologous series RO-CH:CH-COO-C10H6-N:N-C6H4-Cl (ortho) from trans cinnamic acid and α-napthol using ortho chloro aniline has been synthesized and studied with a view to understand and establish the relations between thermotropic liquid crystalline (LC) behaviours of homologues and their molecular structure as a consequence of molecular rigidity and flexibility with changing number of methylene unit present in left n-alkoxy group (-OR) of a molecule. Novel azoester series consists of thirteen (C1 to C18) homologues. C6 to C18 homologues are enantiotropically nematogenic with absence of smectic property. C1 to C5 members are nonliquid crystal. Textures of nematic phase and transition temperatures were determined by an optical polarising microscopy (POM) equipped with a heating stage. Textures of nematic phase are threaded or schilieren. Phase transition curves Cr-N/I and N-I behaved in normal manner in a phase diagram. Analytical and spectral data confirmed molecular structures of homologues. Nematic thermal stability is 145.12 and the degree of mesomorphism vary from 26.0 °C to 46.0 °C at the C14 and C7 homologues respectively. The LC properties of present azoester series are compared with structurally analogous series. Thus, novel series is enantiotropically nematogenic whose mesogenic range is good enough and of middle ordered melting type.
References
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