Synthesis Of Novel Chiral Ionic Liquids Derived From Amino Acids (Alcohols) And Their Application

The task-specific ionic liquid(TSIL)is designed and prepared for the special purpose,in which a functional group is covalently attached to conventional ionic liquids.In general,TSIL could be divided into three different groups:chiral ionic liquids,protic ionic liquid and metal-containing ionic liquids.Due to its supply of a variety of functions,it has been widely used in many fileds such as:organic catalysis,metal ion extraction and gas absorption.In this paper,we focus on the chiral ionic liquid,which was reported in 1997 by Howarth et al.for the first time.After that,chiral ionic liquids are mainly used in asymmetric synthesis,spectroscopic applications,chromatographic applications.However,up to date,chiral resolution by using chiral ionic liquid was limited to the spectroscopic and chromatographic applications.And the chemical structures of reported chiral ionic liquids were simple.It is necessary to develop novel chiral ionic liquids.Thus,we design and prepare a series of novel chiral ionic liquids composed of chiral ureido and imidazolium cation from amino acids and amino alcohol enantiomers.They were used successfully in chiral resolution.The details studies are shown in the followings:1.Enhancement of visual chiral sensing via an anion-binding approach:Novel ionic liquids as the chiral selectors:A novel chiral ionic liquid was formed through three steps with high yields from(S)-phenylalanine as the chiral sensor.Different visual responses toward the enantiomers of amino acids and amino alcohol were generated in water(methanol)and DMSO.The substantial difference contributes to the easy discrimination with visual determination.Furthermore,the mechanism was studied by 1H NMR,FTIR and DFT calculations.2.Enantioeparation of amine and amino alcohol derivatives with Schiff-base reaction:Novel chiral ionic liquids derived from(S)-phenylalaninol were prepared through two steps as the chiral selector.Only(R)-2-amino-2-phenylethan-1-ol could react with 3-formylindole,CuCl2 and the chiral selector to form the coordination complex based on the Schiff-base reaction.Similarly,only(S)-1-phenylethan-l-amine could react with 3-hydroxybenzaldehyde,COCl2 and the chiral selector to form the coordination complex.The e.e.value was more than 0.95 with the yield of 0,94.Moreover,five enantiomers could be realized with chiral resolution by using 1H NMR.3.Specific cooperative effect for the enantiomeric separation of amino acids using aqueous two-phase systems with task-specific ionic liquids:Two different kinds of hydrophilic ionic liquids from(R)-2-amino-1-butanol were synthesized as the solvent.Aqueous two-phase systems(ATPS)based on the chiral ionic liquids and inorganic salt solution were designed and prepared for the enantiomeric separation of racemic amino acids.Various factors influencing separation efficiency were systematically investigated including extraction time,IL volume and temperature.Furthermore,the mechanism was studied by 1H NMR and DFT calculations.Finally,IL-1 was validated with other general amino acids by the same procedures based on ATPS.4.Specific ionic effect for simple and rapid colorimetric sensing assays of amino acids using gold nanoparticles modified with task-specific ionic liquid:A novel task-specific ionic liquid functionalized gold nanoparticle(TSIL-GNP)was successfully prepared and applied in the recognition of amino acids.Particularly,the surface of GNP was modified with the ionic liquid containing carbamido and ester group via thiol,which was characterized by FTIR and TEM.It was successfully applied to recognizing serine,asparticacid,lysine,arginine,and histidine in the presence of Cu2+ through distinctive color changes.Suspension would be generated once a spot of cysteine was added into the GNPs solution,Moreover,the proposed strategy was successfully used to analyze the histidine in urinary samples.