The role of hydrogen bonding in the phase behaviour of supramolecular liquid crystal dimers

Alfonso Martinez-Felipe*, Corrie T. Imrie

*Corresponding author for this work

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

The phase behaviour of equimolar mixtures of 4-octyloxybenzoic acid, OOBA, and either 1-(4-butylazobenzene-4'-oxy)-6-(4-oxypyridine)pentane, BuABO5OPyr, or 1-(4-butylazobenzene-4'-oxy)-6-(4-oxypyridine)hexane, BuABO6OPyr, is reported. OOBA exhibits enantiotropic smectic C and nematic phases, whereas BuABO5OPyr and BuABO6OPyr are not liquid crystalline. Both the OOBA/BuABO5OPyr and OOBA/BuABO6OPyr equimolar mixtures show an enantiotropic smectic A phase identified using Xray diffraction and polarised light microscopy. The liquid crystallinty of the mixtures is attributed, in part, to the formation of a 1:1 hydrogen-bonded complex between OOBA and either BuABO5OPyr or BuA-BO60Pyr. Differences in the transitional properties of the mixtures are accounted for in terms of the average shapes of these 1:1 complexes. Temperature dependent FTIR spectroscopy shows, however, that the formation of the complex is not quantitative in the mixtures but instead a complex mixture exists over the complete temperature range studied, involving the 1:1 complex, both cyclic and open acid dimers, free acid and hence, free BuABOnOPyr molecules. (C) 2015 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)429-437
Number of pages9
JournalJournal of Molecular Structure
Volume1100
Early online date1 Aug 2015
DOIs
Publication statusPublished - 15 Nov 2015

Keywords

  • Liquid crystal dimers
  • Hydrogen bonding
  • Temperature variable FTIR
  • Supramolecular liquid crystals
  • Low molar-mass
  • Side-chain
  • Pyridyl moieties
  • Carboxylic-acid
  • Molecular-orientation
  • Amorphous polymers
  • FTIR spectroscopy
  • IR-spectra
  • Oligomers
  • Mixtures

Cite this

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title = "The role of hydrogen bonding in the phase behaviour of supramolecular liquid crystal dimers",
abstract = "The phase behaviour of equimolar mixtures of 4-octyloxybenzoic acid, OOBA, and either 1-(4-butylazobenzene-4'-oxy)-6-(4-oxypyridine)pentane, BuABO5OPyr, or 1-(4-butylazobenzene-4'-oxy)-6-(4-oxypyridine)hexane, BuABO6OPyr, is reported. OOBA exhibits enantiotropic smectic C and nematic phases, whereas BuABO5OPyr and BuABO6OPyr are not liquid crystalline. Both the OOBA/BuABO5OPyr and OOBA/BuABO6OPyr equimolar mixtures show an enantiotropic smectic A phase identified using Xray diffraction and polarised light microscopy. The liquid crystallinty of the mixtures is attributed, in part, to the formation of a 1:1 hydrogen-bonded complex between OOBA and either BuABO5OPyr or BuA-BO60Pyr. Differences in the transitional properties of the mixtures are accounted for in terms of the average shapes of these 1:1 complexes. Temperature dependent FTIR spectroscopy shows, however, that the formation of the complex is not quantitative in the mixtures but instead a complex mixture exists over the complete temperature range studied, involving the 1:1 complex, both cyclic and open acid dimers, free acid and hence, free BuABOnOPyr molecules. (C) 2015 Elsevier B.V. All rights reserved.",
keywords = "Liquid crystal dimers, Hydrogen bonding, Temperature variable FTIR, Supramolecular liquid crystals, Low molar-mass, Side-chain, Pyridyl moieties, Carboxylic-acid, Molecular-orientation, Amorphous polymers, FTIR spectroscopy, IR-spectra, Oligomers, Mixtures",
author = "Alfonso Martinez-Felipe and Imrie, {Corrie T.}",
year = "2015",
month = "11",
day = "15",
doi = "10.1016/j.molstruc.2015.07.062",
language = "English",
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journal = "Journal of Molecular Structure",
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TY - JOUR

T1 - The role of hydrogen bonding in the phase behaviour of supramolecular liquid crystal dimers

AU - Martinez-Felipe, Alfonso

AU - Imrie, Corrie T.

PY - 2015/11/15

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N2 - The phase behaviour of equimolar mixtures of 4-octyloxybenzoic acid, OOBA, and either 1-(4-butylazobenzene-4'-oxy)-6-(4-oxypyridine)pentane, BuABO5OPyr, or 1-(4-butylazobenzene-4'-oxy)-6-(4-oxypyridine)hexane, BuABO6OPyr, is reported. OOBA exhibits enantiotropic smectic C and nematic phases, whereas BuABO5OPyr and BuABO6OPyr are not liquid crystalline. Both the OOBA/BuABO5OPyr and OOBA/BuABO6OPyr equimolar mixtures show an enantiotropic smectic A phase identified using Xray diffraction and polarised light microscopy. The liquid crystallinty of the mixtures is attributed, in part, to the formation of a 1:1 hydrogen-bonded complex between OOBA and either BuABO5OPyr or BuA-BO60Pyr. Differences in the transitional properties of the mixtures are accounted for in terms of the average shapes of these 1:1 complexes. Temperature dependent FTIR spectroscopy shows, however, that the formation of the complex is not quantitative in the mixtures but instead a complex mixture exists over the complete temperature range studied, involving the 1:1 complex, both cyclic and open acid dimers, free acid and hence, free BuABOnOPyr molecules. (C) 2015 Elsevier B.V. All rights reserved.

AB - The phase behaviour of equimolar mixtures of 4-octyloxybenzoic acid, OOBA, and either 1-(4-butylazobenzene-4'-oxy)-6-(4-oxypyridine)pentane, BuABO5OPyr, or 1-(4-butylazobenzene-4'-oxy)-6-(4-oxypyridine)hexane, BuABO6OPyr, is reported. OOBA exhibits enantiotropic smectic C and nematic phases, whereas BuABO5OPyr and BuABO6OPyr are not liquid crystalline. Both the OOBA/BuABO5OPyr and OOBA/BuABO6OPyr equimolar mixtures show an enantiotropic smectic A phase identified using Xray diffraction and polarised light microscopy. The liquid crystallinty of the mixtures is attributed, in part, to the formation of a 1:1 hydrogen-bonded complex between OOBA and either BuABO5OPyr or BuA-BO60Pyr. Differences in the transitional properties of the mixtures are accounted for in terms of the average shapes of these 1:1 complexes. Temperature dependent FTIR spectroscopy shows, however, that the formation of the complex is not quantitative in the mixtures but instead a complex mixture exists over the complete temperature range studied, involving the 1:1 complex, both cyclic and open acid dimers, free acid and hence, free BuABOnOPyr molecules. (C) 2015 Elsevier B.V. All rights reserved.

KW - Liquid crystal dimers

KW - Hydrogen bonding

KW - Temperature variable FTIR

KW - Supramolecular liquid crystals

KW - Low molar-mass

KW - Side-chain

KW - Pyridyl moieties

KW - Carboxylic-acid

KW - Molecular-orientation

KW - Amorphous polymers

KW - FTIR spectroscopy

KW - IR-spectra

KW - Oligomers

KW - Mixtures

U2 - 10.1016/j.molstruc.2015.07.062

DO - 10.1016/j.molstruc.2015.07.062

M3 - Article

VL - 1100

SP - 429

EP - 437

JO - Journal of Molecular Structure

JF - Journal of Molecular Structure

SN - 0022-2860

ER -