The properties of a new class of reversible, room-temperature, chiral ionic liquids—amidinium carbamates—which are easily made from readily available chemicals, amidines and chiral amino alcohols, are described. The ionic liquid phases are prepared by exposing a 1/1 (mol/mol) mixture of an easily synthesized amidine and an amino alcohol, obtained in one step by reduction of a naturally-occurring amino acid, to CO2 gas; one commercially available amino alcohol with two chiral centers, has been employed as well. All of the amidine-amino alcohol combinations examined, 35 in all, form ionic liquids in this way at room temperature. They are stable indefinitely under an atmosphere of CO2 and they remain liquids well below 0 oC and above room tempereature. The ionic liquids can be reconverted to their non-ionic states after an inert gas (such as N2 or argon) is bubbled through them at room temperature or, more rapidly, at slightly elevated temperatures. The thermal, conductive, viscous, and spectroscopic properties of both the nonionic and ionic phases will be reported and compared. Unlike many other ionic liquids, these need not be prepared and handled under dry conditions and they can be cycled repeatedly between high- and low-polarity states.

We thank the National Science Foundation for its support of this research.