title: Polyiodides in room-temperature ionic liquids.
abstract: Polyiodides, Im-, were formed in room-temperature ionic liquids (RTILs). The RTILs were N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium iodide, [DEME][I], and 1-alkyl-3-methylimidazolium iodide, [Cnmim][I] (n = 1, 2, 3, 4, 6, and 12). In [Cnmim][Im], prepeak and intensity modulation of X-ray diffraction were caused by polyiodides. Above m = 4, polyiodide-mediated local structures were formed, although little alkyl side-chain length, n, dependence was seen in the X-ray diffraction patterns. The viscosity of the mixtures was measured as a function of m to obtain their dynamic properties. The m tendencies of the viscosity and density changed at around m = 4 when fixing n = 4. By127I-NMR, the local environments of only polyiodides were extracted by changing n, m, and the temperature. Doublet/triplet peak splitting of pure [Cnmim][I] (n = 3, 4, and 6) occurred at low temperature. In [Cnmim][Im] (n = 2 and 4), the effect of polyiodides was clarified from the chemical shifts and peak splitting in the NMR spectra. The experimental results support a Grotthuss-type exchange mechanism of iodide between polyiodides.
authors.affiliation: Department of Materials Science and Engineering, National Defense Academy, Yokosuka 239-8686, Japan. ab@nda.ac.jp.
authors.forename: Hiroshi
authors.identifier: http://orcid.org/0000-0002-2153-0540
authors.initials: H
authors.lastname: Abe
authors.affiliation: Department of Materials Science and Engineering, National Defense Academy, Yokosuka 239-8686, Japan. ab@nda.ac.jp.
authors.forename: Masami
authors.initials: M
authors.lastname: Aono
authors.affiliation: Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan.
authors.forename: Tamiko
authors.initials: T
authors.lastname: Kiyotani
authors.affiliation: National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan.
authors.forename: Seiji
authors.identifier: http://orcid.org/0000-0001-8518-0300
authors.initials: S
authors.lastname: Tsuzuki