1. Cluster Structure of Imidazolium Salts in Methanol Controlled by the Balance of Interactions: Cation-Anion, Cation-Solvent, and Anion-Solvent
- Author
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Akihiro Wakisaka, Yuichi Ishikawa, Satoshi Kitaoka, and Kaoru Nobuoka
- Subjects
Solvent ,Electrospray ,chemistry.chemical_compound ,Chemistry ,Inorganic chemistry ,Solvation ,Cluster (physics) ,Halide ,Methanol ,Mass spectrometry ,Analytical Chemistry ,Ion - Abstract
We have studied the cluster structure of 1-butyl-3-methylimidazolium halide, bmimX (X = Cl, Br, I), in methanol solution by means of an electrospray mass spectrometer, which is specially designed for analysis of clusters isolated from solution. In positive ion mode experiments, the ratio of solvated bmim(+), bmim(+)(MeOH)(n) and ion-pair clusters, bmim(bmim(+)X(-))(m) was dependent on the counter anion. As for bmimCl solutions, few solvated bmim(+) clusters were observed, and the ion-pair clusters were clearly observed. On the other hand, bmimBr and bmimI with large anions, the solvated bmim(+) clusters increased obviously, and the ion-pair clusters were in turn remarkably decreased. In negative ion-mode experiments, the solvation for Br(-) by the methanol is found to be the most prominent among those for Cl(-), Br(-), and I(-). These results were reasonably explained in consideration of the balance between ion-solvent and ion-counterion interactions.
- Published
- 2008