Ionic liquid crystals: hexafluorophosphate salts

C.M. Gordon, J.D. Holbrey, A.R. Kennedy, K.R. Seddon

Research output: Contribution to journalArticle

612 Citations (Scopus)

Abstract

A series of novel hexafluorophosphate salts, based on N,N¾-dialkylimidazolium and substituted N-alkylpyridinium cations, display liquid crystalline behaviour at temperatures above their melting point. The temperature range over which liquid crystalline behaviour is observed increases markedly with increasing alkyl chain length. Alkyl substitution at the 3- and 4-positions on the pyridinium ring results in a decrease in the melting point compared with the equivalent unsubstituted salt, but also leads to a large decrease in the tendency towards liquid crystalline behaviour (or mesogenicity). The salts prepared are fully characterised using a wide variety of techniques, including NMR and IR spectroscopy, DSC, and single crystal X-ray diffraction in the case of 1-dodecyl-3-methylimidazolium hexafluorophosphate. The effect of preparing mixtures containing different proportions of two cations is also reported.
LanguageEnglish
Pages2627-2636
Number of pages9
JournalJournal of Materials Chemistry
Volume8
Issue number12
DOIs
Publication statusPublished - 1998

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Ionic Liquids
Liquid Crystals
Ionic liquids
Liquid crystals
Salts
Melting point
Liquids
Crystalline materials
Chain length
Cations
Infrared spectroscopy
Positive ions
Single crystals
X ray diffraction
Temperature

Keywords

  • hexafluorophosphate salts
  • dialkylimidazolium
  • crystalline
  • mesogenicity
  • NMR
  • IR
  • spectroscopy

Cite this

Gordon, C.M. ; Holbrey, J.D. ; Kennedy, A.R. ; Seddon, K.R. / Ionic liquid crystals: hexafluorophosphate salts. In: Journal of Materials Chemistry. 1998 ; Vol. 8, No. 12. pp. 2627-2636.
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Ionic liquid crystals: hexafluorophosphate salts. / Gordon, C.M.; Holbrey, J.D.; Kennedy, A.R.; Seddon, K.R.

In: Journal of Materials Chemistry, Vol. 8, No. 12, 1998, p. 2627-2636.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Ionic liquid crystals: hexafluorophosphate salts

AU - Gordon, C.M.

AU - Holbrey, J.D.

AU - Kennedy, A.R.

AU - Seddon, K.R.

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AB - A series of novel hexafluorophosphate salts, based on N,N¾-dialkylimidazolium and substituted N-alkylpyridinium cations, display liquid crystalline behaviour at temperatures above their melting point. The temperature range over which liquid crystalline behaviour is observed increases markedly with increasing alkyl chain length. Alkyl substitution at the 3- and 4-positions on the pyridinium ring results in a decrease in the melting point compared with the equivalent unsubstituted salt, but also leads to a large decrease in the tendency towards liquid crystalline behaviour (or mesogenicity). The salts prepared are fully characterised using a wide variety of techniques, including NMR and IR spectroscopy, DSC, and single crystal X-ray diffraction in the case of 1-dodecyl-3-methylimidazolium hexafluorophosphate. The effect of preparing mixtures containing different proportions of two cations is also reported.

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KW - mesogenicity

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