301
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Bieri M, Bürgi T. Enantiodiscrimination between anN-Acetyl-L-cysteine SAM and Proline: An In Situ Spectroscopic and Computational Study. Chemphyschem 2006; 7:514-23. [PMID: 16463331 DOI: 10.1002/cphc.200500474] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A combination of attenuated total reflection infrared (ATR-IR) and modulation excitation spectroscopy (MES) is used to study the enantiodiscriminating interactions between proline and a chiral, self-assembled monolayer (SAM) of N-acetyl-L-cysteine on gold. The N-acetyl-L-cysteine SAM consists of a mixture of protonated and deprotonated molecules. Whereas both species are influenced by adsorbed proline, only the deprotonated molecules are involved in enantiodiscrimination. Density functional theory (DFT) calculations reveal that electrostatics dominates the interaction between the two molecules. By modulating the absolute configuration of proline over the chiral SAM, and a subsequent phase-sensitive detection of the periodically varying signals in the ATR-IR spectra, the small spectral differences between the diastereomeric complexes are spotted. The resulting difference spectrum is in qualitative agreement with the spectrum predicted by the DFT calculations.
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Affiliation(s)
- Marco Bieri
- Université de Neuchâtel, Institut de Chimie, Rue Emile-Argand 11, 2007 Neuchâtel (Switzerland)
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302
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Rauls E, Hammer B. The Role of the Chiral Modifier on the Enantioselective Hydrogenation of Methyl Pyruvate on Pt(111). Catal Letters 2006. [DOI: 10.1007/s10562-005-9616-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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303
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Fujita S, Sato H, Kakegawa N, Yamagishi A. Enantioselective Photooxidation of a Sulfide by a Chiral Ruthenium(II) Complex Immobilized on a Montmorillonite Clay Surface: The Role of Weak Interactions in Asymmetric Induction. J Phys Chem B 2006; 110:2533-40. [PMID: 16471852 DOI: 10.1021/jp055254r] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The present work pursued a possibility that enantioselectivity was achieved through weak intermolecular interactions between a catalyst and a substrate. For that purpose, we studied the photooxidation of alpha-ethylbenzyl phenyl sulfide catalyzed by a polypyridyl ruthenium(II) complex as a chiral photosensitizer. No covalent bonding was formed between a catalyst and a substrate, because the complexes used ([Ru(phen)(3)](2+) or [Ru(bpy(3))(2+)]) were coordinatively saturated. Enantiomer excess (ee) was attained to be 30% when a chiral photosensitizer was immobilized on montmorillonite clay. It was even improved to 43% in the presence of an additional chiral auxiliary, dibenzoyl-D(+)-tartaric acid. Notably, no enantioselectivity was achieved when the reaction took place in homogeneous solutions. The ab initio calculations were performed on the stability of an associate composed of a catalyst (metal complex) and a product (sulfoxide) to obtain a clue to reaction mechanisms. The calculations suggest that chiral discrimination is achieved even through noncovalent interactions between a substrate and a chiral sensitizer when the attacking direction by a substrate toward a catalyst is limited sterically on a solid surface.
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Affiliation(s)
- Shuji Fujita
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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304
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Kahr B, Chittenden B, Rohl A. Robert Boyle's chiral crystal chemistry: Computational re-evaluation of enantioselective adsorption on quartz. Chirality 2006; 18:127-33. [PMID: 16385623 DOI: 10.1002/chir.20229] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
While searching for early examples of interactions of organic chromophores with minerals in the context of a systematic study of the process of dyeing crystals, we came across Robert Boyle's description of an experiment that may have been evidence of the enantioselective adsorption of a natural product, carminic acid (7-beta-D-glucopyranosyl-9,10-dihydro-3,5,6,8-tetrahydroxy-1-methyl-9,10-dioxo-2-anthracenecarboxylic acid), to the chiral surfaces of alpha-quartz, three centuries before such interactions became the subject of active chemical investigations. In order to determine whether Boyle did indeed observe enantioselective adsorption--albeit unbeknownst to him--we attempted to dye quartz with carminic acid according to his recipe. Quartz adsorbs carminic acid only because on heating it develops a network of microfissures that adsorb dye. This process depends on capillarity, not on specific non-covalent interactions; there is no evidence of enantioselectivity adsorption to heated crystals or enantioselective epitaxy to unheated crystals. These failures changed the focus of our inquiry: Why have almost all attempts to demonstrate the enantioselective adsorption of additives to quartz crystal surfaces been generally confounding and equivocal? In order to answer this question, we complement our experimental historical re-investigation with contemporary computational techniques for modeling crystal surface structure and the adsorption of additives. Minimizations of the energies associated with the adsorption of carminic acid to relaxed, hydrated d- and l-quartz {10(-)0} surfaces are analyzed in light of quartz's abysmal record as an enantioselective stationary phase.
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Affiliation(s)
- Bart Kahr
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98105-1700, USA.
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305
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Bhatia B, Sholl DS. Enantiospecific Chemisorption of Small Molecules on Intrinsically Chiral Cu Surfaces. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200501655] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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306
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Bhatia B, Sholl DS. Enantiospecific Chemisorption of Small Molecules on Intrinsically Chiral Cu Surfaces. Angew Chem Int Ed Engl 2005; 44:7761-4. [PMID: 16278911 DOI: 10.1002/anie.200501655] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Bhawna Bhatia
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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307
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Oaki Y, Imai H. The Hierarchical Architecture of Nacre and Its Mimetic Material. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200500338] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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308
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Rankin RB, Sholl DS. Structures of Glycine, Enantiopure Alanine, and Racemic Alanine Adlayers on Cu(110) and Cu(100) Surfaces. J Phys Chem B 2005; 109:16764-73. [PMID: 16853135 DOI: 10.1021/jp0535700] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have determined the structures of dense adlayers of glycine and alanine on the Cu(110) and Cu(100) surfaces using plane wave density functional theory. These calculations resolve several experimental controversies regarding these structures. Glycine exists on Cu(110) as a single adlayer structure, while on Cu(100) two distinct glycine adlayers coexist. The glycine structures serve as useful starting points for constructing alanine adlayer structures. We considered separately the adsorption of enantiopure alanine and racemic alanine on each surface. Adlayers of enantiopure alanine are found to be closely related to the adlayers observed for glycine. Racemic alanine adlayers on Cu(110) are structurally analogous to those observed for glycine on this surface and adopt a pseudo-racemate ordering. On Cu(100), in contrast to glycine, racemic alanine is found to adopt a single adlayer structure that is an ordered racemate. Spontaneous segregation of molecular enantiomers does not occur in racemic adsorbed mixtures on either surface. Consideration of the orientationally distinct domains that may exist for each adlayer on these surfaces provides important information for the interpretation of the adlayer domain boundaries that are commonly observed in scanning tunneling microscopy images of amino acid adlayers. Examining this set of amino acid adlayers provides useful insight into the range of subtle behaviors that can arise in these and related systems where chiral molecules form ordered adlayers on flat metal surfaces.
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Affiliation(s)
- Rees B Rankin
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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309
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Chandrasekhar V, Azhakar R, Zacchini S, Bickley JF, Steiner A. Synthesis, Structure, and Stereochemistry of Trinuclear Metal Complexes Formed from the Phosphorus-Based Achiral Tripodal Ligand {P(S)[N(Me)NCHC6H4-o-OH]3} (LH3): Luminescent Properties of L2Cd3·2H2O. Inorg Chem 2005; 44:4608-15. [PMID: 15962968 DOI: 10.1021/ic050395t] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Neutral trinuclear metal complexes L2Cd3 x 2H2O, L2Mn3 x MeOH, and L2Zn3 x MeOH were isolated in the reaction between the phosphorus-centered achiral tris(hydrazone) P(S)[N(Me)N=CHC6H(4)-o-OH]3 (LH3) and the corresponding divalent metal ions. The trinuclear complexes contain two equivalent terminal metal ions (M(t)) and a central metal ion (M(c)). The ligand encapsulates M(t) in a facial N3O3 coordination environment. From the coordination sphere of the two terminal metal ions a pair of phenolic oxygen atoms further coordinate to the central metal ion. The coordination requirements of M(c) are completed by the solvents of coordination. The achiral trianionic tripodal ligand (L)3- induces chirality in the metal complexes. This results in a delta (clockwise) or lambda (anticlockwise) configuration for the terminal metal ions. The enantiomeric complexes 2-4 (delta-delta or lambda-lambda) crystallize as racemic compounds. The supramolecular structures of 2-4 reveal chiral recognition in the solid-state; every molecule with the delta-delta configuration interacts stereospecifically, through C-H...S=P bonds, with two lambda-lambda molecules to generate a one-dimensional polymeric chain. Photophysical studies of the diamagnetic trinuclear complexes reveal that the tricadmium complex is luminescent in the solid state as well as in solution. In contrast LH3 and L2Zn3 x MeOH are nonluminescent.
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310
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Guo P, Tang R, Cheng C, Xi F, Liu M. Interfacial Organization-Induced Supramolecular Chirality of the Langmuir−Schaefer Films of a Series of PPV Derivatives. Macromolecules 2005. [DOI: 10.1021/ma047295b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Peizhi Guo
- CAS Key Laboratory of Colloid, Interface and Chemical thermodynamics, State Key Laboratory of Polymer Physics and Chemistry, Center for Molecular Science, Institute of Chemistry, and Graduate School of the Chinese Academy of Sciences, The Chinese Academy of Sciences, Beijing, 100080, P. R. China
| | - Rupei Tang
- CAS Key Laboratory of Colloid, Interface and Chemical thermodynamics, State Key Laboratory of Polymer Physics and Chemistry, Center for Molecular Science, Institute of Chemistry, and Graduate School of the Chinese Academy of Sciences, The Chinese Academy of Sciences, Beijing, 100080, P. R. China
| | - Caixia Cheng
- CAS Key Laboratory of Colloid, Interface and Chemical thermodynamics, State Key Laboratory of Polymer Physics and Chemistry, Center for Molecular Science, Institute of Chemistry, and Graduate School of the Chinese Academy of Sciences, The Chinese Academy of Sciences, Beijing, 100080, P. R. China
| | - Fu Xi
- CAS Key Laboratory of Colloid, Interface and Chemical thermodynamics, State Key Laboratory of Polymer Physics and Chemistry, Center for Molecular Science, Institute of Chemistry, and Graduate School of the Chinese Academy of Sciences, The Chinese Academy of Sciences, Beijing, 100080, P. R. China
| | - Minghua Liu
- CAS Key Laboratory of Colloid, Interface and Chemical thermodynamics, State Key Laboratory of Polymer Physics and Chemistry, Center for Molecular Science, Institute of Chemistry, and Graduate School of the Chinese Academy of Sciences, The Chinese Academy of Sciences, Beijing, 100080, P. R. China
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311
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Wedyan M, Preston MR. Isomer-selective adsorption of amino acids by components of natural sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005; 39:2115-9. [PMID: 15871245 DOI: 10.1021/es040474o] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We present evidence that under circumstances of low pH and organic-free surfaces an ordinary estuarine sediment can exhibit strong optical isomer selectivity in its absorption of a number of amino acids. This selectivity can also be seen to a lesser degree in the minerals quartz, montmorillonite, and kaolin. Adsorption reactions were performed with racemic amino acid mixtures, and after equilibrium, deviations from a D/L ratio of 1 were measured and in many cases were found to be significant. This was particularly pronounced at pH 4.0, where selective removal of the L isomers by adsorption onto sedimentfractions was almosttotal. Changes in both the nature and degree of selectivity were also observable in different sediment size fractions. While we are at this stage unable to identify the mode of primary selectivity, adsorption experiments with these candidate sediment components, quartz, kaolin, and montmorillonite do exhibit some selective behavior. We believe that the existence of natural chirally selective components in sediment may indicate a new approach to the development of chiral catalysis and synthesis.
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Affiliation(s)
- M Wedyan
- Department of Earth and Ocean Sciences, University of Liverpool, Liverpool L69 3GP, United Kingdom
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312
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Clark LA, Chempath S, Snurr RQ. Simulated adsorption properties and synthesis prospects of homochiral porous solids based on their heterochiral analogs. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:2267-2272. [PMID: 15752015 DOI: 10.1021/la047722e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Molecular simulations of chiral molecules in porous heterochiral materials were performed to investigate fundamental adsorption properties and possibilities for production of homochiral porous solids. Zeolite BEA polymorph A and zeotype UCSB-7K each provide separated pores of opposite chirality. Single enantiomer and racemic mixture adsorption results are presented and indicate that significant equilibrium enantiomeric excesses of 40-70% in UCSB-7K and 10% in BEA can be achieved. Larger, better-fitting molecules display higher enantiomeric excesses. For dimethylallene, which moves on molecular dynamics time scales in UCSB-7K, self-diffusivities vary by almost an order of magnitude between the two opposite-handed UCSB-7K pores for a given enantiomer. The predicted properties indicate that equilibrium and nonequilibrium strategies using related homochiral materials for separations may be successful. To this end, a discussion of strategies for selectively blocking pores of one chirality on the basis of enantiomer segregation is provided.
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Affiliation(s)
- Louis A Clark
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA.
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313
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314
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Horvath JD, Koritnik A, Kamakoti P, Sholl DS, Gellman AJ. Enantioselective Separation on a Naturally Chiral Surface. J Am Chem Soc 2004; 126:14988-94. [PMID: 15535728 DOI: 10.1021/ja045537h] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Kinked-stepped, high Miller index surfaces of metal crystals are chiral and, therefore, exhibit enantiospecific properties. Previous temperature-programmed desorption (TPD) spectra have shown that the desorption energies of R-3-methylcyclohexanone (R-3-MCHO) on the chiral Cu(643)(R) and Cu(643)(S) surfaces are enantiospecific (J. Am. Chem. Soc. 2002, 124, 2384). Here, a comparison of the TPD spectra from Cu(111), Cu(221), Cu(533), Cu(653)(R&S), and Cu(643)(R&S) surfaces reveals that the enantiospecific desorption occurs from the chiral kink sites on the Cu(643) surfaces. Titration of the chiral kink sites with I atoms confirms this assignment of desorption features in the TPD spectra. Finally, the enantiospecific difference in the desorption energies of R- and S-3-MCHO has been used as the basis for demonstration of an enantioselective, kinetic separation of racemic 3-MCHO into its purified components during adsorption and desorption on the Cu(643)(R&S) surfaces.
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Affiliation(s)
- Joshua D Horvath
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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315
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Oaki Y, Imai H. Amplification of chirality from molecules into morphology of crystals through molecular recognition. J Am Chem Soc 2004; 126:9271-5. [PMID: 15281817 DOI: 10.1021/ja048661+] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have found a novel type of morphological chiral tuning on inorganic helical crystals through stereochemical recognition of organic molecules. Helical forms consisting of twisted twins emerged from triclinic crystals under diffusion-limited conditions. The proportion of the right- and left-handed helices was precisely tuned with the addition of a specified amount of chiral molecules, such as d- and l-glutamic acids. The chiral molecules recognized the enantiomeric surface of the triclinic crystal and then changed the growth behavior of the helical morphology. As a result, the microscopic chiral information, at a molecular level, was amplified into the macroscopic helices consisting of inorganic achiral components.
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Affiliation(s)
- Yuya Oaki
- Department of Applied Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan
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316
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317
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318
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319
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Asthagiri A, Sholl DS. Pt thin films on stepped SrTiO3 surfaces: SrTiO3(620) and SrTiO3(622). ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.molcata.2004.03.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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320
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Sato I, Kadowaki K, Ohgo Y, Soai K. Highly enantioselective asymmetric autocatalysis induced by chiral ionic crystals of sodium chlorate and sodium bromate. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.molcata.2004.03.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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