Molecular Crystals and Liquid Crystals, Vol.569, 64-71, 2012
A Novel Mesomorphic Homologous Series of Ethylene Derivatives alpha-4-(4'-n-Alkoxy benzoyloxy) Benzoyl beta-3''-Nitro Phenyl Ethylenes
A novel homologous series of 11 ethylene derivatives has been synthesized and evaluated. The methoxy to pentyloxy homologues are nonmesomorphic, whereas the hexyloxy to dodecyloxy derivatives are enantiotropically smectogenic and enantiotropically nematogenic in character. The tetradecyloxy and hexadecyloxy homologues exhibit only nematogenic character without showing of any smectogenic character. An odd-even effect is not observed in either of the transition curves from a phase diagram. The average smectic and nematic thermal stabilities are 126.7 degrees C and 148.6 degrees C, respectively. The liquid crystal properties of the novel series are compared with other structurally similar compounds. The texture of the nematic phase is a threaded or Schlieren type, and that of smectic phase shows the smectic A type as determined by optical polarizing microscopy. Analytical data support the molecular structures in all cases. The novel series is predominantly nematogenic and partly smectogenic with mesophase temperature ranges between 12 degrees C and 63 degrees C.