Dialkylimidazolium hydrogen bond interaction

ILs can act as both hydrogen bond acceptors (anions) and donors (cations), and as expected, they interact with substances with both acceptor and donor sites. In particular, 1,3-dialkylimidazolium ILs can dissolve a plethora of classical polar and non-polar compounds. All 1,3-dialkylimidazolium ILs reported to date are hygroscopic, and their miscibility with water is largely controlled by the nature of the anion. While salts containing nitrate, chloride, and perchlorate anions are usually miscible with water in all compositions, those associated with hexafluorophosphate and bis(trifluoromethane) sulfonylamidate anions are almost completely immiscible with water.It is also known that an increase in the A-alkyl chain length increases the hydrophobicity for a series of l-alkyl-3-methylimidazolium hexafluorophosphate ILs." The miscibility of water in ILs can be increased by the addition of short-chain alcohols or lowered by the addition of salts (salting-out effect). ... 

In COlL-1, all of the main aspects of the liquid-state structure of room-temperature ionic liquids were already laid out in contributions by several groups, although sometimes still in an incipient way. Hardacre and co-workers reported neutron diffraction studies of short-chain dialkylimidazolium ionic liquids, perfectly illustrating the charge ordering and n-interactions [17]. They also used different spectroscopic and simulation methods to study how the solvation of aromatic and polar molecules (benzene and ethanenitrile, respectively) in the ionic liquids modifies the structure of the media [46] and the balance between the different terms in the interactions coulombic, van der Waals (dispersive), hydrogen bonds and multipolar. 

---