Molecular interactions and normal vibrations of Fe-bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methylimidazolium-Fe-bis(trifluoromethanesulfonyl)imide ionic liquids: A density functional study

Density functional theory is used to obtain the electronic structure and normal vibrations of Fe-bis(trifluoromethanesulfonyl)imide (1:1) and 1-ethyl-3-methylimidazolium-Fe-bis(trifluoromethanesulfonyl)imide (1:1:1) ionic liquids. Different conformers were simulated on the basis of molecular interactions in 1:1 and 1:1:1 systems. Strength of molecular interactions in the ionic liquids was correlated with frequency shifts of characteristic vibrations relative to the corresponding vibration in free anion. The outcomes of the theoretical calculations were qualitatively compared with the experimental results.