Structural Features of Cholinium Based Protic Ionic Liquids through Molecular Dynamics.

An analysis of the complex proton transfer processes in certain protic ionic liquids, based on amino acid anions, has been carried out through ab initio molecular dynamics in the view of finding naturally conductive and pure mediums. The systems analyzed here might serve as chemical prototypes for pure and dry ionic liquids where mobile protons can act as fast charge carriers. We have exploited the natural tendency of these liquids to form a complex network of hydrogen bonds. The presence of such a network allows the naturally repulsive interaction between like charge ions to be weakened to the point that a proton migration process inside the anionic component of the fluid becomes possible. We have also seen that the extent of these proton migrations is sizable for carboxylic based amino acid anions, while it is very limited for sulfur containing ones.