Two new chiral ionic liquids, 1 -((-)-menthoxycarbonylmethylene)-3-methylimidazolium hexafluorophosphateand 1-((-)-menthoxycarbonylmethylene)-3-hexadecylimidazolium hexafluorophosphate, were designed an d prepared. Th...Two new chiral ionic liquids, 1 -((-)-menthoxycarbonylmethylene)-3-methylimidazolium hexafluorophosphateand 1-((-)-menthoxycarbonylmethylene)-3-hexadecylimidazolium hexafluorophosphate, were designed an d prepared. Theirchemical structures were characterized by ~1H-NMR. Reverse atom transfer radical polymerization of methyl methacrylate(MMA) in these two ionic liquids was carried out using AIBN/CuCl_2/bipy as the initiating system. The resultant well-definedpolymethyl methacrylate (PMMA) was employed as a macroinitiator to induce the atom transfer radical polymerization ofmenthyl methacrylate (MnMA) in chlorobenzene, which yielded a PMMA-b-PMnMA diblock copolymer with narrow polydispersity.展开更多
Chiral ionic liquids (CILs) containing imidazolium cations and L-Proline (L-Pro) anions were applied as chiral selector to separate tryptophan (Trp) enantiomers on a C18 column by ligand exchange chromatography. Sever...Chiral ionic liquids (CILs) containing imidazolium cations and L-Proline (L-Pro) anions were applied as chiral selector to separate tryptophan (Trp) enantiomers on a C18 column by ligand exchange chromatography. Several factors influencing Trp enantiomers separation, such as alkyl chain length of CILs, concentrations of Cu2+ and CILs, pH of the mobile phase, flow rate, organic solvent and temperature, were studied. Under the optimal conditions, the Trp enantiomers could be successfully separated within 21 min with the resolution of 2.30. At the same time, some thermodynamical parameters were obtained. The experimental results show that the enthalpy values of the Trp enantiomers are negative, indicating that the separation process is exothermic. And the enthalpy values of D-Trp are larger than those of L-Trp, which indicates that L-Trp could form more stable ternary complexes with tryptophan enantiomers.展开更多
L-（＋）-α-（positive butyl）-leucine ethyl ester bromide chiral ionic liquid was synthesized by using microwave-assisted synthesis method and L-（＋）-α-（positive butyl）-leucine ethyl ester terafluoroborate and h...L-（＋）-α-（positive butyl）-leucine ethyl ester bromide chiral ionic liquid was synthesized by using microwave-assisted synthesis method and L-（＋）-α-（positive butyl）-leucine ethyl ester terafluoroborate and hexafluorophosphate chiral ionic liquids were synthesized by the anion exchange reaction. The structures were characterized by IR, ~1HNMR and structure optimization calculation. The results of studies on physicochemical properties show that they possess better thermal stability, solubility, bio-solubility and high conductivity. They can serve as effective reaction media as well as chiral catalysts. They are presently being investigated as dispersion agents in molecular imprinting ployer.展开更多
Using （S）-（-）-2-chloropropionie acid ethyl ester and N-methylimidazole as raw materials, we designed and synthesized three N-methylimidazolium chiral ionic liquids by the nucleophilic substitution reaction or anio...Using （S）-（-）-2-chloropropionie acid ethyl ester and N-methylimidazole as raw materials, we designed and synthesized three N-methylimidazolium chiral ionic liquids by the nucleophilic substitution reaction or anion exchange reaction. These chiral ionic liquids structures were analyzed with structure optimization calculation, IR, and HNMR. Their reaction mechanism and physical chemistry properties were explored. As a result, these chiral ionic liquids possess optical activity, low melting point, high conductivity, and weak acidity, etc. They can serve as effective reaction media as well as chiral catalysts. They are presently being investigated as dispersion agent in molecular imDrinting, nlover in our laboratory.展开更多
Asymmetric reductive amination of carbonyl compounds was carried out using a novel class of aliphatic quarternary ammonium based chiral ionic liquid. S-(+)-2,3-dihydroxy-N,N,N-tributylpropanaminum bromide chiral ionic...Asymmetric reductive amination of carbonyl compounds was carried out using a novel class of aliphatic quarternary ammonium based chiral ionic liquid. S-(+)-2,3-dihydroxy-N,N,N-tributylpropanaminum bromide chiral ionic liquid has been synthesized, characterized and used for asymmetric reductive amination of carbonyl compounds in the presence of sodium borohydride. These preliminary results are encouraging and advocate dual role of novel ionic liquid as a medium and reducing agent for proficient conversion of ketones to amines, however, reductive amination reaction needs to be established for other substituents.展开更多
Irradiation of cyclohexyl phenyl ketone （1） results in either intra- or intermolecular hydrogen abstraction to af- ford compounds 1-phenylhept-6-en-l-one （2） and a-cyclohexyl benzyl alcohol （3） as photoproducts,...Irradiation of cyclohexyl phenyl ketone （1） results in either intra- or intermolecular hydrogen abstraction to af- ford compounds 1-phenylhept-6-en-l-one （2） and a-cyclohexyl benzyl alcohol （3） as photoproducts, in which 3 has a pair of enantiomers. Herein, two types of chiral hexagonal liquid crystals were prepared to direct the enantioselec- tive photochemical reaction of 1. One of the hexagonal liquid crystals is composed of 1-tetradecyl-3-methyl- imidazolium bromide/p-xylene/H2O with the modification by a chiral inductor. The other one is formed by chiral （S）-3-hexadecyl-1-（1-hydroxy-propan-2-yl）-imidazolium bromide/p-xylene/H2O. The product analysis shows that the latter one can be used as a microreactor to achieve stereoselective photochemical reaction, while the former one produced compound 3 with no enantioselectivity at all.展开更多
A series of novel chiral metal-containing ionic liquids (CMILs) consisting of the cation of crown ether-chelated potassium/ sodium and the anion of chiral amino acids were designed and synthesized. These new CMILs wer...A series of novel chiral metal-containing ionic liquids (CMILs) consisting of the cation of crown ether-chelated potassium/ sodium and the anion of chiral amino acids were designed and synthesized. These new CMILs were used to catalyze the enantioselective cycloaddition of epoxides and carbon dioxide incorporating with the salenCo(OOCCC13) to generate corresponding chiral cyclic carbonates under mild conditions. These new catalysts can be recycled at least five times without significant loss of activity and enantioselectivity.展开更多
基金This work was supported by the National Natural Science Foundation of China (Grants 20174001, 29992590-4) and the Ministry of Education of China for the teaching and research award fund for outstanding young teacher in higher education institutions.
文摘Two new chiral ionic liquids, 1 -((-)-menthoxycarbonylmethylene)-3-methylimidazolium hexafluorophosphateand 1-((-)-menthoxycarbonylmethylene)-3-hexadecylimidazolium hexafluorophosphate, were designed an d prepared. Theirchemical structures were characterized by ~1H-NMR. Reverse atom transfer radical polymerization of methyl methacrylate(MMA) in these two ionic liquids was carried out using AIBN/CuCl_2/bipy as the initiating system. The resultant well-definedpolymethyl methacrylate (PMMA) was employed as a macroinitiator to induce the atom transfer radical polymerization ofmenthyl methacrylate (MnMA) in chlorobenzene, which yielded a PMMA-b-PMnMA diblock copolymer with narrow polydispersity.
基金Project(21176262) supported by the National Natural Science Foundation of ChinaProject(2010WK3029) supported by Science and Technology Program of Hunan Province,China
文摘Chiral ionic liquids (CILs) containing imidazolium cations and L-Proline (L-Pro) anions were applied as chiral selector to separate tryptophan (Trp) enantiomers on a C18 column by ligand exchange chromatography. Several factors influencing Trp enantiomers separation, such as alkyl chain length of CILs, concentrations of Cu2+ and CILs, pH of the mobile phase, flow rate, organic solvent and temperature, were studied. Under the optimal conditions, the Trp enantiomers could be successfully separated within 21 min with the resolution of 2.30. At the same time, some thermodynamical parameters were obtained. The experimental results show that the enthalpy values of the Trp enantiomers are negative, indicating that the separation process is exothermic. And the enthalpy values of D-Trp are larger than those of L-Trp, which indicates that L-Trp could form more stable ternary complexes with tryptophan enantiomers.
基金Funded by the National Natural Science Foundation of China(No.51433008)the Project of Scientific Research of Shaanxi(No.2017GY-182)the Science and Technology Fund Project
文摘L-（＋）-α-（positive butyl）-leucine ethyl ester bromide chiral ionic liquid was synthesized by using microwave-assisted synthesis method and L-（＋）-α-（positive butyl）-leucine ethyl ester terafluoroborate and hexafluorophosphate chiral ionic liquids were synthesized by the anion exchange reaction. The structures were characterized by IR, ~1HNMR and structure optimization calculation. The results of studies on physicochemical properties show that they possess better thermal stability, solubility, bio-solubility and high conductivity. They can serve as effective reaction media as well as chiral catalysts. They are presently being investigated as dispersion agents in molecular imprinting ployer.
基金Funded by the Special Funds of the National Natural Science Foundation of China (No.21174111)
文摘Using （S）-（-）-2-chloropropionie acid ethyl ester and N-methylimidazole as raw materials, we designed and synthesized three N-methylimidazolium chiral ionic liquids by the nucleophilic substitution reaction or anion exchange reaction. These chiral ionic liquids structures were analyzed with structure optimization calculation, IR, and HNMR. Their reaction mechanism and physical chemistry properties were explored. As a result, these chiral ionic liquids possess optical activity, low melting point, high conductivity, and weak acidity, etc. They can serve as effective reaction media as well as chiral catalysts. They are presently being investigated as dispersion agent in molecular imDrinting, nlover in our laboratory.
文摘Asymmetric reductive amination of carbonyl compounds was carried out using a novel class of aliphatic quarternary ammonium based chiral ionic liquid. S-(+)-2,3-dihydroxy-N,N,N-tributylpropanaminum bromide chiral ionic liquid has been synthesized, characterized and used for asymmetric reductive amination of carbonyl compounds in the presence of sodium borohydride. These preliminary results are encouraging and advocate dual role of novel ionic liquid as a medium and reducing agent for proficient conversion of ketones to amines, however, reductive amination reaction needs to be established for other substituents.
基金The authors thank the National Key Basic Research Program of China，the National Natural Science Foundation of China (Nos.91027041 and 20920102033) for financial support,and Key Laboratory of Photochemical Conversion and Optoelectronic Materials,TIPC,CAS for financial support
文摘Irradiation of cyclohexyl phenyl ketone （1） results in either intra- or intermolecular hydrogen abstraction to af- ford compounds 1-phenylhept-6-en-l-one （2） and a-cyclohexyl benzyl alcohol （3） as photoproducts, in which 3 has a pair of enantiomers. Herein, two types of chiral hexagonal liquid crystals were prepared to direct the enantioselec- tive photochemical reaction of 1. One of the hexagonal liquid crystals is composed of 1-tetradecyl-3-methyl- imidazolium bromide/p-xylene/H2O with the modification by a chiral inductor. The other one is formed by chiral （S）-3-hexadecyl-1-（1-hydroxy-propan-2-yl）-imidazolium bromide/p-xylene/H2O. The product analysis shows that the latter one can be used as a microreactor to achieve stereoselective photochemical reaction, while the former one produced compound 3 with no enantioselectivity at all.
基金supported by the National Natural Science Foundation of China (20973086)
文摘A series of novel chiral metal-containing ionic liquids (CMILs) consisting of the cation of crown ether-chelated potassium/ sodium and the anion of chiral amino acids were designed and synthesized. These new CMILs were used to catalyze the enantioselective cycloaddition of epoxides and carbon dioxide incorporating with the salenCo(OOCCC13) to generate corresponding chiral cyclic carbonates under mild conditions. These new catalysts can be recycled at least five times without significant loss of activity and enantioselectivity.
