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Dallocchio R, Dessì A, Sechi B, Peluso P. Molecular Dynamics Simulations of Amylose- and Cellulose-Based Selectors and Related Enantioseparations in Liquid Phase Chromatography. Molecules 2023; 28:7419. [PMID: 37959839 PMCID: PMC10647714 DOI: 10.3390/molecules28217419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023] Open
Abstract
In the last few decades, theoretical and technical advancements in computer facilities and computational techniques have made molecular modeling a useful tool in liquid-phase enantioseparation science for exploring enantioselective recognition mechanisms underlying enantioseparations and for identifying selector-analyte noncovalent interactions that contribute to binding and recognition. Because of the dynamic nature of the chromatographic process, molecular dynamics (MD) simulations are particularly versatile in the visualization of the three-dimensional structure of analytes and selectors and in the unravelling of mechanisms at molecular levels. In this context, MD was also used to explore enantioseparation processes promoted by amylose and cellulose-based selectors, the most popular chiral selectors for liquid-phase enantioselective chromatography. This review presents a systematic analysis of the literature published in this field, with the aim of providing the reader with a comprehensive picture about the state of the art and what is still missing for modeling cellulose benzoates and the phenylcarbamates of amylose and cellulose and related enantioseparations with MD. Furthermore, advancements and outlooks, as well as drawbacks and pitfalls still affecting the applicability of MD in this field, are also discussed. The importance of integrating theoretical and experimental approaches is highlighted as an essential strategy for profiling mechanisms and noncovalent interaction patterns.
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Affiliation(s)
| | | | | | - Paola Peluso
- Unit of Enantioselective Chromatography and Molecular Recognition, Institute of Biomolecular Chemistry ICB, Secondary Branch of Sassari, CNR, Traversa La Crucca 3, Regione Baldinca, Li Punti, 07100 Sassari, Italy; (R.D.); (A.D.); (B.S.)
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2
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Tsui HW, Huang SX, Tseng TH. Heterogenous adsorption mechanisms for describing enantioselective retention in normal-phase liquid chromatography. J Chromatogr A 2023; 1704:464140. [PMID: 37315447 DOI: 10.1016/j.chroma.2023.464140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/02/2023] [Accepted: 06/07/2023] [Indexed: 06/16/2023]
Abstract
In this study, the enantioselective retention behaviors of methyl mandelate (MM) and benzoin (B) were investigated using Chiralpak IB as a sorbent and ethanol, 1-propanol, and 1-butanol as solvent modifiers in the normal-phase mode. For both MM and B, similar chiral recognition mechanisms were observed, potentially involving at least two types of chiral adsorption sites. With a retention model describing local retention behaviors, an enantioselectivity model based on a three-site model was proposed to describe the data. Fitted parameters were also used to analyze the contributions of each type of adsorption site to the apparent retention behavior. Combining the local retention model with the three-site model provided a qualitative and quantitative explanation for the correlation between modifier concentration and enantioselectivity. Overall, our results indicated that heterogeneous adsorption mechanisms are a key aspect in understanding enantioselective retention behaviors. Distinct local adsorption sites contribute differently to apparent retention behaviors, with these contributions being influenced by the mobile phase composition to varying degrees. Hence, enantioselectivity changes with variations in modifier concentration.
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Affiliation(s)
- Hung-Wei Tsui
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608 Taiwan.
| | - Si-Xian Huang
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608 Taiwan
| | - Ting-Hsien Tseng
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608 Taiwan
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3
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Tsui HW, Hsieh CH, Zhan CF. Effect of mobile-phase modifiers on the enantioselective retention behavior of methyl mandelate with an amylose 3,5-dimethylphenylcarbamate chiral stationary phase under reversed-phase conditions. J Sep Sci 2023; 46:e2200651. [PMID: 36401614 DOI: 10.1002/jssc.202200651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/21/2022]
Abstract
In this study, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, acetone, and tert-butanol were used as organic modifiers in reversed-phase mode chiral liquid-chromatography to systematically investigate the effects of mobile phase components on the enantioselective retention behavior of methyl mandelate with immobilized amylose 3,5-dimethylphenylcarbamate-based sorbent called Chiralpak IA. A two-site enantioselective model was used to obtain information on the recognition mechanisms by observing the dependence of the enantioselectivity and retention factor difference on the modifier content. Similar enantioselective retention behaviors were observed for all modifiers, and characteristic modifier concentration points (PL , PM , and PH ) were identified. At modifier concentrations up to PM , the weakened hydrophobic environment resulted in polymer structural relaxation, which changed the recognition mechanisms. By contrast, at concentrations beyond PH , considerably different enantioselectivity behaviors were observed, indicating that the existence of dipole-dipole interaction, which was stronger at higher modifier concentrations, contributed to the retention mechanisms. The concentrations at which these characteristic points occurred were dependent on the carbon number of the modifier molecule. Modifiers with more carbon numbers facilitated the transition in the enantioselective behaviors. These results demonstrated that the proposed method can provide a physically consistent quantitative description of enantioselective retention behavior in reversed-phase mode.
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Affiliation(s)
- Hung-Wei Tsui
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan
| | - Ching-Hung Hsieh
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan
| | - Chao-Fu Zhan
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan
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4
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Tsui HW, Zhang HL, Hsieh CH. Effect of 2-propanol content on solute retention mechanisms determined using amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phase under normal- and reversed-phase conditions. J Chromatogr A 2021; 1650:462226. [PMID: 34087518 DOI: 10.1016/j.chroma.2021.462226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 04/12/2021] [Accepted: 04/29/2021] [Indexed: 11/29/2022]
Abstract
The electrostatic interactions between chiral solutes and polysaccharide (PS)-based chiral selectors are the key to achieving chiral recognition; however, PS-based sorbents, derivatized of phenyl moieties, can exhibit considerably non-polar characteristics, and they are also useful for the separation of enantiomers in the reversed-phase mode. In this study, an immobilized amylose 3,5-dimethylphenylcarbamate-based sorbent was used to investigate the balance between electrostatic interactions and solvophobic interactions, with complementary effects on solute retention behavior when the isopropanol (IPA) concentration was altered. It was proposed that in both normal- and reversed-phase modes, information on the retention mechanisms could be obtained by observing the curvature of the logarithm of the retention factor versus the logarithm of the IPA concentration, and the slope values of the curves were related to the number of displaced IPA molecules upon solute adsorption. Using the proposed model and the two-site adsorption model, the retention behaviors of pantolactone (PL) enantiomers in both normal- and reversed-phase modes were investigated. The PL-sorbent interactions were classified into four types: electrostatic/enantioselective, electrostatic/nonselective, solvophobic/enantioselective, and solvophobic/nonselective. At IPA concentrations below 50 vol.% in n-hexane, the retention behaviors of PL were dominated by electrostatic/enantioselective sites, whereas at IPA concentrations beyond 50 vol.%, the solvophobic interactions of PL-sorbent were strengthened and mostly nonselective. By contrast, in the reversed-phase mode, a reverse in the enantiomeric elution order of PL was observed at 10 vol.% IPA, and considerably different enantioselectivity behaviors were found below and above 20 vol.%, indicating an abrupt change in the sorbent molecular environment. At IPA concentrations beyond 40 vol.%, the presence of PL-sorbent electrostatic interactions enhanced chiral recognition.
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Affiliation(s)
- Hung-Wei Tsui
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608 Taiwan.
| | - Hong-Lin Zhang
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608 Taiwan
| | - Ching-Hung Hsieh
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608 Taiwan
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5
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Tsui HW, Ye PW, Huang SX. Effect of solvents on the chiral recognition mechanisms of immobilized cellulose-based chiral stationary phase. J Chromatogr A 2020; 1637:461796. [PMID: 33387913 DOI: 10.1016/j.chroma.2020.461796] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 02/06/2023]
Abstract
The effect of solvents on the enantioselectivities of four structurally similar chiral solutes with a cellulose derivative-based chiral stationary phase, Chiralpak IB, were studied using acetone (AC), 2-propanol (IPA), and tert-butanol (TBA) separately as polar modifiers. The enantioselectivities α of benzoin and methyl mandelate decrease with an increase in modifier concentration CM, whereas the enantioselectivity of pantolactone increased with increasing AC concentration. These results were attributed to the heterogeneous adsorption mechanisms of enantiomers. To interpret the dependence of enantioselectivity on modifier content, an enantioselectivity model based on a two-site adsorption model was proposed. The dependence of α on CM was inferred to be mainly due to the distinct modulating effects of modifier concentration on the two adsorption sites: the nonselective type-I site and enantioselective type-II site. The model fitted the benzoin data satisfactorily over a wide TBA concentration range. The retention factors as a function of TBA concentration were successfully deconvoluted for each site. With the use of the proposed model, it was inferred that the chiral recognitions of benzoin and methyl mandelate were mainly achieved by the presence of an aromatic group adjacent to the hydroxyl group. When using IPA and TBA separately as modifiers, the presence of an aromatic group adjacent to the ketone group mainly contributed to the nonselective π interactions and enantioselective steric interactions, respectively. These results, along with those of the modifier adsorption isotherms, determined using the perturbation method, as well as the retention behaviors of various achiral solutes, indicate that the molecular recognition mechanism of IB sorbent is highly sensitive to the adsorbate's molecular geometry. The molecular environment of the sorbent can be controlled using different modifiers, leading to distinct adsorption and retention mechanisms.
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Affiliation(s)
- Hung-Wei Tsui
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608 Taiwan.
| | - Pei-Wen Ye
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608 Taiwan
| | - Si-Xian Huang
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608 Taiwan
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6
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Tsui HW, Chou PY, Ye PW, Chen SC, Chen YW. Effects of the Sorbent Backbone and Side Chain on Retention Mechanisms Using Immobilized Polysaccharide-Based Stationary Phases in Normal Phase Mode. Chromatographia 2020. [DOI: 10.1007/s10337-020-03898-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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7
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Sugi KS, Bhat S, Nag A, Ganesan P, Mahendranath A, Pradeep T. Ligand structure and charge state-dependent separation of monolayer protected Au25 clusters using non-aqueous reversed-phase HPLC. Analyst 2020; 145:1337-1345. [DOI: 10.1039/c9an02043h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We demonstrate a systematic flow rate dependent study of three different aliphatic ligand protected Au25 clusters, with three commercially available reversed-phase HPLC columns.
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Affiliation(s)
- Korath Shivan Sugi
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE)
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai 600 036
- India
| | - Shridevi Bhat
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE)
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai 600 036
- India
| | - Abhijit Nag
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE)
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai 600 036
- India
| | - Paramasivam Ganesan
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE)
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai 600 036
- India
| | - Ananthu Mahendranath
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE)
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai 600 036
- India
| | - Thalappil Pradeep
- DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE)
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai 600 036
- India
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8
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Abstract
Stereospecific recognition of chiral molecules plays an important role in nature as the basis of the interaction of chiral bioactive compounds with the chiral target structures. In separation sciences such as chromatographic and capillary electromigration techniques, interactions between chiral analytes and chiral selectors, i.e., the formation of transient diastereomeric complexes in thermodynamic equilibria, are the basis for chiral separations. Due to the large structural variety of chiral selectors, different structural features contribute to the overall chiral recognition process. This introductory chapter briefly summarizes the present understanding of the structural enantioselective recognition processes for various types of chiral selectors.
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Affiliation(s)
- Gerhard K E Scriba
- Department of Pharmaceutical Chemistry, University of Jena, Jena, Germany.
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9
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Tsui HW, Cheng KT, Lin AY, Chen SC, Hung YL, Chou PY. Solvent effects on the retention mechanisms of an amylose-based sorbent. J Chromatogr A 2018; 1556:64-72. [DOI: 10.1016/j.chroma.2018.04.065] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/06/2018] [Accepted: 04/26/2018] [Indexed: 11/25/2022]
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10
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Zhu B, Zhao F, Yu J, Wang Z, Song Y, Li Q. Chiral separation and a molecular modeling study of eight azole antifungals on the cellulose tris(3,5-dichlorophenylcarbamate) chiral stationary phase. NEW J CHEM 2018. [DOI: 10.1039/c8nj01845f] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Four immobilized polysaccharide-based chiral stationary phases have been examined for their enantioselectivity on azole analytes using normal phase liquid chromatography.
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Affiliation(s)
- Bolin Zhu
- School of Pharmacy
- Shenyang Pharmaceutical University
- Shenyang
- P. R. China
| | - Fan Zhao
- School of Life Science and Bio-pharmaceutics
- Shenyang Pharmaceutical University
- Shenyang
- P. R. China
| | - Jia Yu
- School of Pharmacy
- Shenyang Pharmaceutical University
- Shenyang
- P. R. China
| | - Zhaokun Wang
- School of Pharmacy
- Shenyang Pharmaceutical University
- Shenyang
- P. R. China
| | - Yongbo Song
- School of Life Science and Bio-pharmaceutics
- Shenyang Pharmaceutical University
- Shenyang
- P. R. China
| | - Qing Li
- School of Pharmacy
- Shenyang Pharmaceutical University
- Shenyang
- P. R. China
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12
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Zhao B, Oroskar PA, Wang X, House D, Oroskar A, Oroskar A, Jameson C, Murad S. The Composition of the Mobile Phase Affects the Dynamic Chiral Recognition of Drug Molecules by the Chiral Stationary Phase. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:11246-11256. [PMID: 28826215 DOI: 10.1021/acs.langmuir.7b02337] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
More than half of all pharmaceuticals are chiral compounds. Although the enantiomers of chiral compounds have the same chemical structure, they can exhibit marked differences in physiological activity; therefore, it is important to remove the undesirable enantiomer. Chromatographic separation of chiral enantiomers is one of the best available methods to get enantio-pure substances, but the optimization of the experimental conditions can be very time-consuming. One of the most widely used chiral stationary phases, amylose tris(3,5-dimethylphenyl carbamate) (ADMPC), has been extensively investigated using both experimental and computational methods; however, the dynamic nature of the interaction between enantiomers and ADMPC, as well as the solvent effects on the ADMPC-enantiomer interaction, are currently absent from models of the chiral recognition mechanism. Here we use QM/MM and molecular dynamics (MD) simulations to model the enantiomers of flavanone on ADMPC in either methanol or heptane/2-propanol (IPA) (90/10) to elucidate the chiral recognition mechanism from a new dynamic perspective. In atomistic MD simulations, the 12-mer model of ADMPC is found to hold the 4/3 left-handed helical structure in both methanol and heptane/IPA (90/10); however, the ADMPC polymer is found to have a more extended average structure in heptane/IPA (90/10) than in methanol. This results from the differences in the distribution of solvent molecules close to the backbone of ADMPC leads to changes in the distribution of the (φ, ψ) dihedral angles of the glycoside bond (between adjacent monomers) that define the structure of the polymer. Our simulations have shown that the lifetime of hydrogen bonds formed between ADMPC and flavanone enantiomers in the MD simulations are able to reproduce the elution order observed in experiments for both the methanol and the heptane/IPA solvent systems. Furthermore, the ratios of hydrogen-bonding-lifetime-related properties also capture the solvent effects, in that heptane/IPA (90/10) is found to make the separation between the two enantiomers of flavanone less effective than methanol, which agrees with the experimental separation factors of 0.9 versus 0.4 for R/S, respectively.
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Affiliation(s)
- Binwu Zhao
- Orochem Technologies, Inc., 340 Shuman Boulevard, Naperville, Illinois 60563, United States
| | - Priyanka A Oroskar
- Orochem Technologies, Inc., 340 Shuman Boulevard, Naperville, Illinois 60563, United States
| | - Xiaoyu Wang
- Department of Chemical Engineering, Illinois Institute of Technology , 10 West 33rd Street, Perlstein Hall, Chicago, Illinois 60616, United States
| | - David House
- Orochem Technologies, Inc., 340 Shuman Boulevard, Naperville, Illinois 60563, United States
| | - Anil Oroskar
- Orochem Technologies, Inc., 340 Shuman Boulevard, Naperville, Illinois 60563, United States
| | - Asha Oroskar
- Orochem Technologies, Inc., 340 Shuman Boulevard, Naperville, Illinois 60563, United States
| | - Cynthia Jameson
- Department of Chemical Engineering, University of Illinois at Chicago , 810 South Clinton Street, Chicago, Illinois 60607, United States
| | - Sohail Murad
- Department of Chemical Engineering, Illinois Institute of Technology , 10 West 33rd Street, Perlstein Hall, Chicago, Illinois 60616, United States
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13
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Effect of solvent composition on the van’t Hoff enthalpic curve using amylose 3,5-dichlorophenylcarbamate–based sorbent. J Chromatogr A 2017; 1515:179-186. [DOI: 10.1016/j.chroma.2017.08.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 06/19/2017] [Accepted: 08/03/2017] [Indexed: 11/18/2022]
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14
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Ryoki A, Yokobatake H, Hasegawa H, Takenaka A, Ida D, Kitamura S, Terao K. Topology-Dependent Chain Stiffness and Local Helical Structure of Cyclic Amylose Tris(3,5-dimethylphenylcarbamate) in Solution. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00706] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Akiyuki Ryoki
- Department
of Macromolecular Science, Graduate School of Science, Osaka University, 1-1
Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Hiromi Yokobatake
- Department
of Macromolecular Science, Graduate School of Science, Osaka University, 1-1
Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Hirokazu Hasegawa
- Department
of Macromolecular Science, Graduate School of Science, Osaka University, 1-1
Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
- Materials
Characterization Laboratories, Toray Research Center, Inc., 3-3-7, Sonoyama, Otsu, Shiga 520-8567, Japan
| | - Aya Takenaka
- Materials
Characterization Laboratories, Toray Research Center, Inc., 3-3-7, Sonoyama, Otsu, Shiga 520-8567, Japan
| | - Daichi Ida
- Department
of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Shinichi Kitamura
- Graduate
School of Life and Environmental Sciences, Osaka Prefecture University, Gakuen-cho,
Nakaku, Sakai 599-8531, Japan
| | - Ken Terao
- Department
of Macromolecular Science, Graduate School of Science, Osaka University, 1-1
Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
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15
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Hsieh HY, Wu SG, Tsui HW. Retention models and interaction mechanisms of benzene and other aromatic molecules with an amylose-based sorbent. J Chromatogr A 2017; 1494:55-64. [DOI: 10.1016/j.chroma.2017.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/01/2017] [Accepted: 03/06/2017] [Indexed: 11/30/2022]
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16
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Elucidation of adsorption mechanisms of solvent molecules with distinct functional groups on amylose tris(3,5-dimethylphenylcarbamate)-based sorbent. J Chromatogr A 2016; 1460:123-34. [DOI: 10.1016/j.chroma.2016.07.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 07/07/2016] [Accepted: 07/07/2016] [Indexed: 11/24/2022]
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17
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Scriba GKE. Chiral recognition in separation science - an update. J Chromatogr A 2016; 1467:56-78. [PMID: 27318504 DOI: 10.1016/j.chroma.2016.05.061] [Citation(s) in RCA: 182] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 05/17/2016] [Accepted: 05/19/2016] [Indexed: 12/26/2022]
Abstract
Stereospecific recognition of chiral molecules is an important issue in various aspects of life sciences and chemistry including analytical separation sciences. The basis of analytical enantioseparations is the formation of transient diastereomeric complexes driven by hydrogen bonds or ionic, ion-dipole, dipole-dipole, van der Waals as well as π-π interactions. Recently, halogen bonding was also described to contribute to selector-selectand complexation. Besides structure-separation relationships, spectroscopic techniques, especially NMR spectroscopy, as well as X-ray crystallography have contributed to the understanding of the structure of the diastereomeric complexes. Molecular modeling has provided the tool for the visualization of the structures. The present review highlights recent contributions to the understanding of the binding mechanism between chiral selectors and selectands in analytical enantioseparations dating between 2012 and early 2016 including polysaccharide derivatives, cyclodextrins, cyclofructans, macrocyclic glycopeptides, proteins, brush-type selectors, ion-exchangers, polymers, crown ethers, ligand-exchangers, molecular micelles, ionic liquids, metal-organic frameworks and nucleotide-derived selectors. A systematic compilation of all published literature on the various chiral selectors has not been attempted.
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Affiliation(s)
- Gerhard K E Scriba
- Friedrich Schiller University Jena, Department of Pharmaceutical/Medicinal Chemistry, Philosophenweg 14, 07743 Jena, Germany.
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18
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de Juan Fernández L, Fuentes de Arriba ÁL, Monleón LM, Rubio OH, Alcázar Montero V, Rubio LS, Morán JR. An Enantioselective Benzofuran-Based Receptor for Dinitrobenzoyl-Substituted Amino Acids. European J Org Chem 2016. [DOI: 10.1002/ejoc.201501457] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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19
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White RJ, Shuttleworth PS, Budarin VL, De Bruyn M, Fischer A, Clark JH. An Interesting Class of Porous Polymer--Revisiting the Structure of Mesoporous α-D-Polysaccharide Gels. CHEMSUSCHEM 2016; 9:280-8. [PMID: 26785060 DOI: 10.1002/cssc.201501354] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/19/2015] [Indexed: 05/06/2023]
Abstract
The processes involved in the transformation of non-porous, native polysaccharides to their highly porous equivalents introduce significant molecular complexity and are not yet fully understood. In this paper, we propose that distinct changes in polysaccharide local short-range ordering promotes and directs the formation of meso- and micro-pores, which are investigated here using N2 sorption, FTIR, and solid-state (13)C NMR. It is found that an increase in the overall double helical amylose content, and their local association structures, are responsible for formation of the porous polysaccharide gel phase. An exciting consequence of this local ordering change is elegantly revealed using a (19)F NMR experiment, which identifies the stereochemistry-dependent diffusion of a fluorinated chiral probe molecule (1-phenyl-2,2,2-trifluoroethanol) from the meso- to the micro-pore region. This finding opens opportunities in the area of polysaccharide-based chiral stationary phases and asymmetric catalyst preparation.
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Affiliation(s)
- Robin J White
- Green Chemistry Centre of Excellence, University of York, Department of Chemistry, Heslington, York, YO10 5DD, UK.
- FMF-Freiburger Materialforschungszentrum, Stefan-Meier-Straße 21, 79104, Freiburg, Germany.
- Sustainable Catalytic Materials Group, Hydrogen Technologies Division, Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstraße 2, 79110, Freiburg, Germany.
| | - Peter S Shuttleworth
- Departamento de Física de Polímeros, Elastómeros y Aplicaciones Energéticas, Instituto de Ciencia y Tecnología de Polímeros, CSIC, c/Juan de la Cierva 3, 28006, Madrid, Spain
| | - Vitaliy L Budarin
- Green Chemistry Centre of Excellence, University of York, Department of Chemistry, Heslington, York, YO10 5DD, UK
| | - Mario De Bruyn
- Green Chemistry Centre of Excellence, University of York, Department of Chemistry, Heslington, York, YO10 5DD, UK
| | - Anna Fischer
- Universität Freiburg, Institut für Anorganische und Analytische Chemie, Albertstraße 21, 79104, Freiburg, Germany
| | - James H Clark
- Green Chemistry Centre of Excellence, University of York, Department of Chemistry, Heslington, York, YO10 5DD, UK
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Schnitzler EG, Poopari MR, Xu Y, Jäger W. Rotational spectroscopy of methyl benzoylformate and methyl mandelate: structure and internal dynamics of a model reactant and product of enantioselective reduction. Phys Chem Chem Phys 2015; 17:21942-9. [PMID: 26234934 DOI: 10.1039/c5cp03114a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Pure rotational spectra of a prototypical prochiral ester, methyl benzoylformate (MBF), and the product of its enantioselective reduction, (R)-(-)-methyl mandelate (MM), were measured in the range of 5-16 GHz, using a cavity-based molecular beam Fourier-transform microwave spectrometer. Potential conformers were located using density functional theory calculations, and one conformer of each species was identified experimentally. The minimum energy conformer of MBF, in which the ester group is in a Z orientation, was observed for the first time. Based on an atoms-in-molecules analysis, MBF contains a weak CH···O=C hydrogen bond between the carbonyl oxygen atom of the ester group and the nearest hydrogen atom of the aromatic ring. In the minimum energy conformer of MM, the ester group is oriented to accommodate a hydrogen bond between the hydrogen atom of the hydroxyl group and the carbonyl oxygen atom (OH···O=C), rather than the sp(3) oxygen atom (OH···O-C). For both species, splittings of the rotational transitions were observed, which are attributed to methyl internal rotation, and the orientations and barrier heights of the methyl tops were determined precisely. The barrier heights for MBF and MM are 4.60(2) and 4.54(3) kJ mol(-1), respectively, which are consistent with values predicted by high-level wavefunction-based calculations. On the basis of an atoms-in-molecules analysis, we propose that destabilization of the sp(3) oxygen atom of the ester group most directly dictates the barrier height.
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Affiliation(s)
- Elijah G Schnitzler
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada.
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Ma S, Tsui HW, Spinelli E, Busacca CA, Franses EI, Wang NHL, Wu L, Lee H, Senanayake C, Yee N, Gonella N, Fandrick K, Grinberg N. Insights into chromatographic enantiomeric separation of allenes on cellulose carbamate stationary phase. J Chromatogr A 2014; 1362:119-28. [DOI: 10.1016/j.chroma.2014.08.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 07/30/2014] [Accepted: 08/09/2014] [Indexed: 10/24/2022]
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Tsui HW, Franses EI, Wang NHL. Effect of alcohol aggregation on the retention factors of chiral solutes with an amylose-based sorbent: Modeling and implications for the adsorption mechanism. J Chromatogr A 2014; 1328:52-65. [DOI: 10.1016/j.chroma.2013.12.078] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 12/11/2013] [Accepted: 12/26/2013] [Indexed: 11/29/2022]
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