title: Effects of dissolved water on Li+ solvation in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ionic liquid studied by NMR.
abstract: (1)H and (7)Li NMR chemical shifts of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide-water solutions in the presence and absence of lithium bis(trifluoromethanesulfonyl)amide were determined at 293.2 K over a wide range of water concentrations from 0.0156 to 1.16 mol kg(-1). These results revealed the attractive interaction between water molecule and Li(+) as well as the hydrogen bonding among water molecules. Moreover, self-diffusion coefficients of water, 1-ethyl-3-methylimidazolium cation, Li(+), and bis(trifluoromethanesulfonyl)amide anion in the ionic liquid solutions at various water contents were determined by (1)H, (7)Li, and (19)F NMR techniques. It was found that Li(+) is averagely hydrated by eight water molecules in the ionic liquid solutions. Furthermore, (7)Li longitudinal relaxation times of Li(+) in the ionic liquid solutions at 293.2 K were measured with two different magnetic fields and various water contents. The mean one-jump distances of Li(+) in the ionic liquid solutions were estimated from the correlation times and the self-diffusion coefficients. A comparison between the hydrodynamic radius and the mean one-jump distance of Li(+) suggested the formation of water channels in the ionic liquid solutions.
authors.affiliation: Department of Chemistry and Applied Chemistry, Graduate School of Science and Engineering, Saga University , Honjo-machi, Saga 840-8502, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Umecky
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Takamuku
authors.forename: Tomoya
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Eiji
authors.initials: E
authors.lastname: Kawai
authors.forename: Masaya
authors.initials: M
authors.lastname: Takagi
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Funazukuri