title: Lewis Acidity/Basicity Changes in Imidazolium Based Ionic Liquids Brought About by Impurities.
abstract: We herein report on the effect that water molecules, present as impurities, in the vicinity of an ionic liquid model structure, may induce on the Lewis acidity/basicity patterns normally observed in these materials. Depending on the position and orientation of water, the Lewis acidity/basicity pattern changes from "normal distribution" (i.e., the basicity located at the anion moiety and the acidity located at the cation fragment) to "bifunctional distribution" (i.e., the acidity and basicity located at the cation moiety). In some specific cases, there appears a third Lewis acidity/basicity distribution, where water may bind both the cation and the anion of the ion pair; a response we tentatively call "amphoteric". These effects are clearly traced to the hydrogen bond formation ability of water to coordinate different regions of pure ionic liquids taken as references.
authors.affiliation: Centro de Química Médica, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo , Código Postal 7710162, Santiago, Chile.
authors.forename: Marcela
authors.initials: M
authors.lastname: Gazitúa
authors.affiliation: Departamento de Física, Facultad de Ciencias, Universidad de Chile , Casilla 653, Santiago, Chile.
authors.forename: Patricio
authors.initials: P
authors.lastname: Fuentealba
authors.affiliation: Departamento de Química, Facultad de Ciencias, Universidad de Chile , Casilla 653, Santiago, Chile.
authors.forename: Renato
authors.initials: R
authors.lastname: Contreras
authors.affiliation: Departamento de Física, Facultad de Ciencias, Universidad de Chile , Casilla 653, Santiago, Chile.|Departamento de Química, Facultad de Ciencias, Universidad de Chile , Casilla 653, Santiago, Chile.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Ormazábal-Toledo