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8217729 
Journal Article 
Effect of flexible chain on mesomorphic properties of alkyloxy substituted 4-chloroazobenzene liquid crystals 
Kamruzzaman; Roushown, ALI; Karim, R; Chowdhury, SI; Hasan, T 
2021 
Yes 
Asian Journal of Chemistry
ISSN: 0970-7077
EISSN: 0975-427X 
Asian Publication Corporation 
33 
5 
1159-1164 
English 
Three rod-shaped alkyloxy substituted 4-chloroazobenzene liquid crystals, 1-(4-chlorophenyl)-2-[4-(alkyloxy)phenyl]diazene (hexayl, octyl and nonyl as flexible oxyalkyl chain) have been synthesized by diazotization of p-chloroaniline with phenol and subsequently performed etherification reaction with different alkyl bromides. The structures of the substituted 4-chloroazobenzene liquid crystals have been characterized by spectroscopic methods. The mesomorphic properties of the liquid crystals were examined by polarizing optical microscope (POM) and differential scanning calorimetry (DSC). All the oxyalkyl homologues of chloro substituted azobenzene showed enantiotropic smectic A (SmA) mesophase, which was understood clearly by the texture of the compounds employing polarizing optical microscope (POM) analysis. During heating scan in DSC analyses melting points, SmA-isotropic temperature and enthalphy changes associated with SmA-isotropic transition showed a remarkable impact on the spacer length of 4-chloro azobenzene derivatives. © 2021 Chemical Publishing Co.. All rights reserved. 
Azobenzene; Diazene; Isotropic temperature; Liquid crystal; Mesophase; Smectic phase