title: Infrared Spectroscopy of Ionic Liquids Consisting of Imidazolium Cations with Different Alkyl Chain Lengths and Various Halogen or Molecular Anions with and without a Small Amount of Water.
abstract: Infrared spectroscopy was performed on ionic liquids (ILs) that had imidazolium cations with different alkyl chain lengths and various halogen or molecular anions with and without a small amount of water. The molar concentration normalized absorbance due to+C-H vibrational modes in the range of 3000 to 3200 cm-1was nearly identical for ILs that had imidazolium cations with different alkyl chain lengths and the same anions. A close correlation was found between the red-shifted+C-H vibrational modes, the chemical shift of+C(2)-H proton, and the energy stabilization of the hydrogen-bonding interaction. The vibrational modes of the water molecules interacting with anions in the range between 3300 and 3800 cm-1was examined. The correlation between the vibrational frequencies of water, the frequencies of+C-H vibrational modes, and the center frequency of intermolecular vibrational modes due to ion pairs was discussed.
authors.affiliation: Advanced ICT Research Institute, National Institute of Information and Communications Technology , 588-2 Iwaoka, Kobe 651-2492, Japan.
authors.forename: Toshiki
authors.identifier: 0000-0002-9503-171X
authors.initials: T
authors.lastname: Yamada
authors.affiliation: Advanced ICT Research Institute, National Institute of Information and Communications Technology , 588-2 Iwaoka, Kobe 651-2492, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Tominari
authors.affiliation: Advanced ICT Research Institute, National Institute of Information and Communications Technology , 588-2 Iwaoka, Kobe 651-2492, Japan.
authors.forename: Shukichi
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology , 4-2-1 Nukuikitamachi, Koganei, Tokyo 184-8795, Japan.
authors.forename: Maya
authors.initials: M
authors.lastname: Mizuno