title: Symmetry Breaking in Chiral Ionic Liquids Evidenced by Vibrational Optical Activity.
abstract: Ionic liquids (ILs) are receiving increasing interest for their use in synthetic laboratories and industry. Being composed of charged entities, they show a complex and widely unexplored dynamic behavior. Chiral ionic liquids (CILs) have a high potential as solvents for use in asymmetric synthesis. Chiroptical methods, owing to their sensitivity towards molecular conformation, offer unique possibilities to study the structure of these chiral ionic liquids. Raman optical activity proved particularly useful to study ionic liquids composed of amino acids and the achiral 1-ethyl-3-methylimidazolium counterion. We could substantiate, supported by selected theoretical methods, that the achiral counterion adopts an overall chiral conformation in the presence of chiral amino acid ions. These findings suggest that in the design of chiral ionic liquids for asymmetric synthesis, the structure of the achiral counter ion also has to be carefully considered.
authors.affiliation: Department of Physical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, 1211, Geneva, Switzerland. patric.oulevey@unige.ch.
authors.forename: Patric
authors.identifier: 0000-0002-2442-3046
authors.initials: P
authors.lastname: Oulevey
authors.affiliation: Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
authors.forename: Sandra
authors.initials: S
authors.lastname: Luber
authors.affiliation: Department of Physical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, 1211, Geneva, Switzerland.
authors.forename: Birte
authors.initials: B
authors.lastname: Varnholt
authors.affiliation: Department of Physical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, 1211, Geneva, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bürgi
keywords: Raman spectroscopy; density functional theory; ionic liquids; molecular dynamics; optical activity