EVIDENCE FOR HYDROGEN-BONDING IN SOLUTIONS OF 1-ETHYL-3-METHYLIMIDAZOLIUM HALIDES, AND ITS IMPLICATIONS FOR ROOM-TEMPERATURE HALOGENOALUMINATE(III) IONIC LIQUIDS

Multinuclear NMR spectroscopy and conductivity measurements showed that the 1-ethyl-3-methylimidazolium cation, [emim](+), not only forms strong hydrogen bonds (using all three ring protons H-2, H-4 and H-5) with halide ions in polar molecular solvents (e.g. ethanenitrile) and ionic liquids, but that it exists in a quasi-molecular state, [emim]X, in non-polar solvents (e.g. trichloro- and dichloromethane), showing a conventional aromatic stacking phenomenon.