title: Depolarization of water in protic ionic liquids.
abstract: A mixture of the protic ionic liquid mono-methylammonium nitrate with 1.6 wt% water was investigated from Car-Parrinello molecular dynamics simulations. In contrast to imidazolium-based ionic liquids, the cation possesses strong directional hydrogen bonds to water and all hydrogen bonds in the mixture have a comparable strength. This results in a good incorporation of water into the hydrogen bond network of mono-methylammonium nitrate and a tetrahedral hydrogen bond coordination of water. Hence, one might expect a larger dipole moment of water in the investigated mixture compared to neat water due to the good hydrogen bond network incorporation and the charged vicinity of water in the protic ionic liquid. However, the opposite is observed pointing to strong electrostatic screening in protic ionic liquids. Additionally, the influence of water on the properties of the protic ionic liquid is discussed.
authors.affiliation: Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstr. 2, D-04103 Leipzig, Germany. bkirchner@uni-leipzig.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Zahn
authors.forename: Katharina
authors.initials: K
authors.lastname: Wendler
authors.forename: Luigi
authors.initials: L
authors.lastname: Delle Site
authors.forename: Barbara
authors.initials: B
authors.lastname: Kirchner
mesh_terms: D006860:Hydrogen Bonding; D052578:Ionic Liquids / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D052578:Ionic Liquids; D000644:Quaternary Ammonium Compounds; D014867:Water