A new homologous series of nonamphiphilic liquid crystals viz; n-propyl-p-[p’-n-alkoxy cinnamoyloxy] cinnamates with cis confugration is synthesized and studied with a view to understand the effect of molecular structure on mesomorphic properties of substances which may be useful to the various fields of applications. Methyl to pentyl and hexadecyl homologues are nonmesomorphic, hexyl to octyl, decyl, dodecyl and tetradecyl homologues are mesomorphic i.e. nematogenic in character without exhibition of any smectic character. A phase diagram is drawn from the transition temperatures as determined from hot stage polarizing microscope of homologues against the number of carbon atoms in n-alkyl chain of left n-alkoxy terminal end group. Solid-isotropic or solid nematic transition temperature curve follows a zigzag path of rising and falling throughout the series as series is ascended in normal manner. Nematicisotropic transition curve initially rises and then, shows descending tendency as series is ascended. Thus, it follows usual established trend as expected. Wellknown odd-even effect is observed for nematic-isotropic transition curve. Analytical data support the structures of molecules. The enantiotropic nematic mesophase appeared for all the homologues, is of threaded type as determined from miscibility metod. Thermal stability for nematic is 183.80C and mesomorphic range is short which varies from 8.00C to 27.0C. mesomorphic properties of titled homologous series (1) are compared with structurally similar homologous series (A),(B) and (C).
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