Molecular Crystals and Liquid Crystals, Vol.562, 76-84, 2012
Synthesis and Mesomorphic Characteristics of Fluoroaniline Derivatives with Different Lateral Groups
Two new homologous series of liquid crystals viz. 4-(4'-n-alkoxybenzoyloxy)-2-chlorophenylazo-4"-fluorobenzenes(I) and 4-(4'-n-alkoxybenzoyloxy)-2-methylphenyl azo-4"-fluorobenzenes(II) with terminal fluoro, lateral chloro(I) and methyl(II) group and central ester and azo linkages are synthesized and their mesomorphic properties are studied. Both the series are similar in molecular structure with the difference in their lateral substitutions; series I has chloro group and series II has methyl group as laterally substituted groups. All the twelve homologues of each of the series are mesogenic in nature. Series I shows nematic mesophase from the first C-1 to the last C-16 derivative synthesized; smectic mesophase is exhibited by last two viz. C-14 and C-16 derivative, where as all the members from C-1 to C-16 of series II only show nematic mesophase. The nematic mesophase shows marble texture and the smectic mesophase shows Schlirene texture of the Smectic C variety. Both the series are compared with structurally related series.
Keywords:Azo and ester central linkage;chloro and methyl lateral groups;homologues series;mesophase thermal stability;smectic C and nematic mesophase