Bio ionic liquids and water mixtures: a structural study

In this study we have explored, by means of ab initio molecular dynamics, a subset of three different water/cho(+)- phe(-) mixtures. We present both structural and dynamical information of these mixtures as revealed by accurate ab initio computations of the forces acting on the atoms. We highlight the presence of a strong hydrogen bond network between the anions, and the persistence of such interaction even at very high water concentration. Furthermore, we show that the water molecules favour the establishment of hydrogen bond contacts with IL ions, up to 1 : 1.5 IL/water molar ratio. Finally we point out the possible bridging role of a water molecule, namely it can insert between a cation and an anion and give rise to a three-body adduct.