Synthesis and Characterization of a Glycine-L-Histidine-Based Chiral Ionic Liquid and Enantioselectivity Evaluation by Fluorescence Spectroscopy

摘要

A chiral ionic liquid (CIL) derived from the dipeptide glycine-L-histidine (Gly-L-His) cation and bis(trifluoroethyl)sulfonyl imide (NTF2) anion was prepared. The CIL was synthesized via ion-exchange and evaluated for purity, melting points, thermal stability, and chiral recognition ability. The thermal decomposition temperature of [Gly-L-His][NTF2] CIL was 356°C. The melting point of the CIL was ~100°C. The CIL was found to have a fluorescence emission peak with a λ_(max) at 440 nm upon excitation at 364 nm. Fluorescence spectroscopy studies showed that the CIL exhibited chiral recognition ability for enantiomers of naproxen, propranolol, and 2,2,2-trifluoroanthr-yl ethanol. The glycine-L-histidine bis(trifluoroethyl) sulfonyl imide IL effectively served as a solvent and chiral selector. The high thermal stability of this CIL indicates potential to be used as a solvent and chiral selector in high temperature reactions and as a stationary phase for gas chromatography.