Non-symmetric chiral liquid crystal dimers. Preparation and characterisation of the (S)-(benzylidene-4 '-substitutedaniline)-2 ''-methylbutyl-4 '''-(4 ''''-phenyloxy)-benzoateoxy)hexanoates

Guan-Yeow Yeap*, Faridah Osman, Corrie T Imrie

*Corresponding author for this work

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The properties of six chiral non-symmetric dimers belonging to the family of (S)-(benzylidene-4'-substitutedaniline)-2 ''-methylbutyl-4'''-(4 ''''-phenyloxy)benzoate-oxy)hexanoates are described. The terminal substituents on the 4-benzylidene-4'-substituted fragment are H, Cl, Br, I, CH3 and C2H5. All six dimers exhibit an enantiotropic chiral nematic phase. The relationship between the chiral nematicisotropic transition temperature and the terminal substituent is discussed in terms of the size of the substituent and its effect of the molecular shape, and its ability to interact with mesogenic group to which it is attached. The C2H5-substituted dimer also shows an enantiotropic monolayer chiral smectic C phase, the formation of which is attributed to the enhanced molecular inhomogeneity arising from the longer alkyl chain. The weak smectic tendencies seen for the halogen-substituted dimers are attributed to potentially repulsive interactions between the ester links that would occur in an intercalated smectic arrangement which would be expected for dimers of this type. (C) 2016 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)118-125
Number of pages8
JournalJournal of Molecular Structure
Volume1111
Early online date20 Jan 2016
DOIs
Publication statusPublished - 5 May 2016

Keywords

  • Liquid crystal dimers
  • Non-symmetric dimers
  • Chirality
  • Bend nematic phase
  • Mesogenic linking unit
  • Behavior
  • Tetramers
  • Oligomers
  • Azobenzene
  • Trimers
  • Spectroscopy
  • Intercalate
  • Moiety

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