A homologous series with -COO- and -N=N-, as central groups have been synthesized by treating p-n-alkoxy benzoyl chlorides with p-methoxy –p/-hydroxy azobenzene. All the homologues of the series are mesomorphic in nature. The nematic type mesophase commences from the very first member of the series. Polymesomorphism is exhibited by tetradecyl homologue i.e. smectic and nematic mesophases appear, one after another. Hexadecyl member is purely smectogenic. On plotting transition temperatures versus number of carbon atoms in nalkyl chain of left n- alkoxy terminal, a phase diagram is obtained. Solid–isotropic /mesomorphic transition curve, shows usual zigzag path of rising and falling. Nematic-isotropic and smectic – isotropic transition curves behave in normal manner with and without odd-even effect respectively. The series is high melting type with considerable mesomorphic range. Thermal stability and other mesogenic properties are comparable with structurally similar known series. Analytical data support the structure. Transition temperatures are determined by hot stage polarizing microscope. Texture of nematic and smectic mesophases confirmed by miscibility method. Nematic mesophase is of threaded type and that of smectic mesophase are focal conic fan shaped of type smectic-A for tetradecyl and smectic-C for hexadecyl homologue.
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