Synthesis and Application of (S)‐Nicotine‐Based Chiral Ionic Liquids in Enantiomeric Recognition by Using Fluorescence Spectroscopy

Abstract

AbstractThe present report discusses the synthesis, characterization and application of novel chiral ionic liquids (CILs) derived from an enantiopure alkaloid (S)‐nicotine. The synthesis of the CILs was initiated by the preparation of (−)‐bornyl chloroacetate from (−)‐borneol and monochloroacetic acid and then used for the quaternization of (S)‐nicotine. The derivatives of the parent CIL were obtained via anion‐metathesis reactions with sodium salts of dicyanamide and dioctyl sulfosuccinate. The synthesis of the respective compounds was confirmed through NMR (1H,13C) spectroscopy, mass spectrometry, and FTIR. The thermal stability and optical activity of the CILs were analysed through TGA, DTG and polarimetry. All the CILs obtained were liquid at room temperature and exhibited thermal stability up to 150 °C. The potential of chiral ionic liquids as enantiomeric recognizing agents for six amino acids (phenylalanine, proline, valine, alanine, leucine, histidine) was determined through fluorescence spectroscopy. CILs performed well against enantiomers of all amino‐acid with maximum selectivity 1.22 (phenylalanine) and fluorescence enhancement 24.90 : 23.79 (ID/Io : IL/Io) for enantiomers of leucine.