l‐Lysine‐derived ionic liquids as chiral ligands of Zn(II) complexes used in ligand‐exchange CE

Abstract

Amino acid ionic liquids (AAILs) with L-lysine (L-Lys) as anion were synthesized and applied as new chiral ligands in Zn(II) complexes for chiral ligand-exchange CE. After effective optimization, baseline enantioseparation of seven pairs of dansylated amino acids was achieved with a buffer of 100.0 mM boric acid, 5.0 mM ammonium acetate, 3.0 mM ZnSO4 , and 6.0 mM [C6 mim][L-Lys] at pH 8.2. To validate the unique behavior of AAILs, a comparative study between the performance of Zn(II)-L-Lys and Zn(II)-[C6 mim][L-Lys] systems was conducted. In Zn(II)-[C6 mim][L-Lys] system, it has been found that the improved chiral resolution could be obtained and the migration times of the three test samples were markedly prolonged. Then the separation mechanism was further discussed. The role of [C6 mim][L-Lys] indicated clearly that the synthesized AAILs could be used as chiral ligands and would have potential utilization in separation science in future.

Chiral Separations by Capillary Electrophoresis and related Techniques with Different Chiral Selectors: A Review

“…LECE is the most frequently used method in this field as a result of the compatible complexity of amino acids with metal ions. Some recent studies in the literature show that amino acid and similar amino amide-based ILs can be applied with high selectivity as chiral ligands, especially in the separation of amino acid enantiomers in LECE [251][252][253][254][255][256]. Cyclofructans (CFs), which are macrocyclic oligosaccharides (cycloinulo-oligosaccharides), are one of the new generation chiral selectors whose effectiveness is known.…”

Application of Chiral Ionic Liquid-Modified Gold Nanoparticles in the Chiral Recognition of Amino Acid Enantiomers

“…Chiral ILs, as the chiral solvents or chiral inducers, have been successfully applied in asymmetric synthesis, 25,26 gas chromatography, 27 LC, 28,29 and CE. 30–33…”

“…Chiral ILs, as the chiral solvents or chiral inducers, have been successfully applied in asymmetric synthesis, 25,26 gas chromatography, 27 LC, 28,29 and CE. [30][31][32][33] In this work, two chiral ILs, namely 1-ethyl-3-methylimidazole L-tartrate (EMIML-Tar) and 1-ethyl-3-methylimidazole L-lactate (EMIML-Lac), were used as the chiral molecules to adsorb onto AuNP surfaces to create chirality. Ionic liquid-modified AuNPs were characterized by transmission electron microscopy (TEM), infrared (IR) spectroscopy, UV-vis spectroscopy, and CE, and were further applied in the chiral recognitions of tryptophan (Trp), tyrosine (Tyr), and phenylalanine (Phe) enantiomers.…”

Development of a capillary electrophoresis system with Mn(ii) complexes and β-cyclodextrin as the dual chiral selectors for enantioseparation of dansyl amino acids and its application in screening enzyme inhibitors

“…Importantly, the species of available central ions and chiral ligands were quite limited, leading to restricted application. [30][31][32] Although several CLE-CE systems with AAILs as the chiral ligands have been probed, 5,18,19,[33][34][35][36][37][38][39][40][41][42] it is still crucial to search novel AAILs ligands and construct effective CLE-CE systems with new central metal ions in chiral separation. [21][22][23][24][25][26][27] It should be noted that up to now, only a few papers have been published with using other metal ions, such as Co(II) or Ni(II), as the central ions in the CLE-CE systems, 23,28,29 however, baseline enantioseparation could not be obtained in most cases.…”

“…In recent years, amino acid ionic liquids (AAILs) have attracted great attention as its unique advantages, such as convenient synthesis, low cost, good biodegradability, excellent chiral stability, reduced toxicity and high biocompatibility. [30][31][32] Although several CLE-CE systems with AAILs as the chiral ligands have been probed, 5,18,19,[33][34][35][36][37][38][39][40][41][42] it is still crucial to search novel AAILs ligands and construct effective CLE-CE systems with new central metal ions in chiral separation.…”