Anion conformational patterns and bulk properties in bis(perfluoroalkylsulfonyl)imide -based ionic liquids studied with X-Ray diffraction and Molecular Dynamics simulations

The structure of four ionic liquids, composed of non-aromatic, N-methyl-N-propylpyrrolidinium cations and different fluorinated, strongly hydrophobic symmetric and asymmetric bis(perfluoroalkylsulfonyl)imide anions, is investigated by means of X-ray diffraction experiments and fully atomistic Molecular Dynamics simulations. The very good agreement between experimental and calculated diffraction patterns validates the force field assumed. The simulation results are used to shade light on the anions conformational equilibria and to access detailed information on the morphology of these electrochemically-relevant room temperature ionic liquids.