Synthesis and mesomorphic properties of nonsymmetric liquid crystalline dimers containing azobenzene groups

Rahman, Md Lutfor and Jahimin Asik @ Abd. Rashid, and Kumar, Sandeep P. and Sidik Silong, and M. Z A Rahman, (2009) Synthesis and mesomorphic properties of nonsymmetric liquid crystalline dimers containing azobenzene groups. Phase Transitions, 82 (3). pp. 228-239. ISSN 0141-1594

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Abstract

Four novel nonsymmetric dimers containing azobenzene mesogenic groups were synthesized. The nonsymmetric dimers compounds namely, ethyl 4-[(4-{4-(4-((4-nitrophenyl)diazenyl)phenoxy)alkyloxy}phenyl)diazenyl]benzoate were obtained from the alkylation of ethyl 4-[(4-(4-bromoalkyloxy)phenyl) diazenyl]benzoate with 4-[(4-nitrophenyl)diazenyl]phenol. The mesomorphic properties of the compounds were determined by DSC and polarizing optical microscopy. The first member of the series was nonliquid crystalline while all other homologues display nematic and smectic A phases. The trans-azobenzene groups of the dimers display a high-intensity -* transition at about 365 nm and a low-intensity n-* transition at around 465 nm, therefore, photochromism can be achieved by the introduction of the azo linkage to the dimeric liquid crystalline molecules.

Item Type: Article
Uncontrolled Keywords: Azobenzene, Cis-trans isomers, Mesophase, Nematic, Nonsymmetric dimmers, Smectic
Subjects: ?? QD901-999 ??
Divisions: SCHOOL > School of Science and Technology
Depositing User: ADMIN ADMIN
Date Deposited: 17 Mar 2011 04:14
Last Modified: 19 Oct 2017 06:50
URI: http://eprints.ums.edu.my/id/eprint/1540

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