Non-symmetrical liquid crystal dimers armed with azobenzene and 1,2,3-triazole-cholesterol

Arwa Alshargabi, Guan Yeow Yeap*, Wan Ahmad Kamil Mahmood, Chun Chieh Han, Hong-Cheu Lin, Daisuke Takeuchi

*Corresponding author for this work

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

New non-symmetrical dimers which contain respective side units of azobenzene and 1,2,3-triazole-choloesteral have been synthesised from the reaction between 6-azido-[4-(4-acetylphenylazo)phenoxy]alkane and cholesteryl-4-(prop-2-ynyloxy)benzoate. The results show that the derivatives of 6-bromo[4-(4-acetylphenylazo)phenoxy]alkanes which possess the odd alkyl spacers exhibit dimesomorphism of N and SmA phases whilst the members with even numbers are non-mesogenic. However, the 6-azido-[4-(4-acetylphenylazo)phenoxy]-alkanes show N and SmA phases in a wide temperature range. On heating and cooling the target compounds cholesteryl 4-[(1-(6-(4-(4ʹ-acetylphenylazo)phenoxy)alkyl)-1H-1,2,3-triazol-4-yl)methoxy]benzoate show chiral nematic (oily streak and fan-shaped texture) and focal conic texture characteristics of smectic A phases with high thermal stability. Present investigation also reveals the effect of the spacer length upon the phase transition temperature. Intercalated arrangement is favoured by the molecules in the smectic phase. The observation is well established by XRD measurement wherein the actual molecular length is smaller than the theoretical value.

Original languageEnglish
Pages (from-to)1337-1349
Number of pages13
JournalLiquid Crystals
Volume42
Issue number9
DOIs
StatePublished - 2 Sep 2015

Keywords

  • 1,2,3-triazole-cholesterol
  • azobenzene
  • chiral nematic
  • non-symmetrical liquid crystals
  • smectic

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