title: The formation of imidazolium salt intimate (contact) ion pairs in solution.
abstract: 1-n-Butyl-2,3-dimethylimidazolium (BMMI) ionic liquids (ILs) associated with different anions undergo H/D exchange preferentially at 2-Me group of the imidazolium in deuterated solvents. This process is mainly related to the existence of ion pairs rather than the anion basicity. The H/D exchange occurs in solvents (CDCl3 and MeCN for instance) in which intimate contact ion pairs are present and the anion possesses a labile H in its structure, such as hydrogen carbonate and prolinate. In D2 O, separated ion pairs are formed and the H/D exchange does not occur. A plausible catalytic cycle is that the IL behaves as a neutral base in the course of all H/D exchange processes. NMR experiments, density functional calculations, and molecular dynamics simulations corroborate these hypotheses.
authors.affiliation: Institute of Chemistry-UFRGS, Av. Bento Gonçalves, 9500 Porto Alegre 91501-970 RS (Brazil).
authors.forename: Marcileia
authors.initials: M
authors.lastname: Zanatta
authors.forename: Anne-Lise
authors.initials: AL
authors.lastname: Girard
authors.forename: Nathalia M
authors.initials: NM
authors.lastname: Simon
authors.forename: Gunter
authors.initials: G
authors.lastname: Ebeling
authors.forename: Hubert K
authors.initials: HK
authors.lastname: Stassen
authors.forename: Paolo R
authors.initials: PR
authors.lastname: Livotto
authors.forename: Francisco P
authors.initials: FP
authors.lastname: dos Santos
authors.forename: Jairton
authors.initials: J
authors.lastname: Dupont
keywords: NMR spectroscopy; contact ion pairs; density functional calculations; ionic liquids; molecular dynamics