Cation–anion–water interactions in aqueous mixtures of imidazolium based ionic liquids

We have examined the cation–anion–water interactions in aqueous mixtures of imidazolium ionic liquids (ILs) over the whole composition range using FTIR spectroscopy. Changes in the peak positions or band areas of OH vibrational modes of water and CH vibrational modes of imidazolium cation as a function of IL concentration indicated a diminishing trend in hydrogen-bonding network of water and qualitative changes in solution structures. 1H NMR chemical shifts of C(2)H, HC(4)C(5)H and alkyl chain protons of imidazolium cation provided useful information about the comparative strength of cation–anion–water interactions.