ABSTRACT
A newly synthesized ester homologous series viz Isobutyl-4-(4’-n-alkoxy-3’-methoxy cinnamoyloxy) cinnamates is synthesized to study the effect of branching of the alkyl group. Eleven homologs were synthesized. Among these eleven homologues first seven derivatives C1 to C7 of the investigated series are nonmesomorphic by nature. The rest of the homologs are monotropically smectogenic by nature; thus, the presently investigated series is predominately smectogenic by nature without exhibiting a nematic mesophase. Transition temperatures and textures of synthesized compounds were observed through an optical polarizing microscope equipped with a heating stage. The textures of smectogenic mesophase are focal conic fan-shaped. Some representative members were characterized by IR, 1HNMR, mass spectroscopy and elemental analysis. Transition temperatures of homologues are plotted versus the number of carbon atoms present in n-alkyl chain of left n-alkoxy terminal end group. Isotropic-smectic / smectic-isotropic transition curve behaves in a normal ascending manner. Thermal stability and other mesogenic characteristics are compared with other structurally similar homologous series The mesogenic phase length ranges between 11⁰ C and 22⁰ C and is of the middle-order melting type.
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