Raman and ab initio studies of simple and binary 1-alkyl-3-methylimidazolium ionic liquids

R.W. Berg, M. Deetlefs, K.R. Seddon, Irene Shim, J.M. Thompson

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Abstract

Raman spectra of the ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF6]), 1-hexyl-3-methylimidazolium chloride ([C(6)mim]Cl), and 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)mim][PF6]), and binary mixtures thereof, have been assigned using ab initio MP2 calculations. The previously reported anti and gauche forms of the [C(4)mim](+) cation have been observed, and this study reveals this to be a general feature of the long-chain I-alkyl derivatives. Analysis of mixtures Of [C(6)mim]Cl and [C(6)mim][PF6] has provided information on the nature of the hydrogen bonding between the imidazolium headgroup and the anions, and the invariance of the essentially 50:50 mixture of the predominant conformers informs on the nature of glass formation in these systems.
Original languageEnglish
JournalJournal of physical chemistry b
Volume109
Issue number40
Pages (from-to)19018-19025
ISSN1520-6106
Publication statusPublished - 2005

Cite this

Berg, R. W., Deetlefs, M., Seddon, K. R., Shim, I., & Thompson, J. M. (2005). Raman and ab initio studies of simple and binary 1-alkyl-3-methylimidazolium ionic liquids. Journal of physical chemistry b, 109(40), 19018-19025.