title: Choline saccharinate and choline acesulfamate: ionic liquids with low toxicities.
abstract: Choline saccharinate and choline acesulfamate are two examples of hydrophilic ionic liquids, which can be prepared from easily available starting materials (choline chloride and a non-nutritive sweetener). The (eco)toxicity of these ionic liquids in aqueous solution is very low in comparison to other types of ionic liquids. A general method for the synthesis and purification of hydrophilic ionic liquids is presented. The method consists of a silver-free metathesis reaction, followed by purification of the ionic liquid by ion-exchange chromatography. The crystal structures show a marked difference in hydrogen bonding between the two ionic liquids, although the saccharinate and the acesulfamate anions show structural similarities. The optimized structures, the energetics, and the charge distribution of cation-anion pairs in the ionic liquids were studied by density functional theory (DFT) and second-order (Møller-Plesset) perturbation theory calculations. The occupation of the non-Lewis orbitals was considered to obtain a qualitative picture of the Lewis structures. The calculated interaction energies and the dipole moments for the ion pairs in the gas phase were discussed.
authors: Laboratory of Coordination Chemistry and Biomolecular Architecture, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
authors: Peter
authors: P
authors: Nockemann
authors: Ben
authors: B
authors: Thijs
authors: Kris
authors: K
authors: Driesen
authors: Colin R
authors: CR
authors: Janssen
authors: Kristof
authors: K
authors: Van Hecke
authors: Luc
authors: L
authors: Van Meervelt
authors: Simone
authors: S
authors: Kossmann
authors: Barbara
authors: B
authors: Kirchner
authors: Koen
authors: K
authors: Binnemans