Recognition in Chiral Ionic Liquids: The Achiral Cation Makes the Difference

By simulating butan-2-ol dissolved in the chiral ionic liquid 1-ethyl-3-methylimidazolium (S)-alaninate, we investigate the chiral recognition of butan-2-ol in the ionic liquid. The hydrogen bonding between the chiral anion and both enantiomers of butan-2-ol is similar; however, both chiral molecules (anion and alcohol) induce an asymmetry in the achiral cation which leads to a more favorable environment for the alcohol in the heterochiral system as compared to the homochiral system and hence provides an energetic stabilization of the former.