Chiral discrimination in NMR spectroscopy

Buckingham, A. D.

doi:10.1017/s0033583515000074

Cited by 7 publications

(5 citation statements)

References 11 publications

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“…Lately, the influence of magnetic fields on the properties of chiral molecules has been a subject of great interest. − Recently, the influence of magnetic field on the mobility of chirally polarized mixtures of 1-phenylethanol was studied using proton nuclear magnetic resonance ( 1 H NMR) . It was shown that the diffusion coefficients in the pure form and in the chirally polarized mixture of 1-phenylethanol molecules tend to be equalized when the magnetic field is increased.…”

Section: Introductionmentioning

confidence: 99%

Influence of Magnetic Field on the Mobility of Aromatic Chiral Molecules

et al. 2016

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The influence of magnetic fields on the properties of chiral molecules is of great interest nowadays. This work presents an (1)H NMR study of the mobility of 1-phenylethanol and 1-phenyl-1-propanol molecules in pure forms and in chirally polarized mixtures in external magnetic fields. Molecular mobility is shown to be dependent on the strength of the external magnetic field and chiral mixing. It could be assumed that the mobility changes are caused by rotational and magnetic interactions between induced magnetic moments of the aromatic molecules and the external magnetic field; intermolecular interactions are also essential. The results are important for the tasks related to enantiomer separation.

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Section: Introductionmentioning

confidence: 99%

Influence of Magnetic Field on the Mobility of Aromatic Chiral Molecules

et al. 2016

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“…From Eqs. ( 14), (18) and (19), we conclude that . Experimentally, the enantiodiscrimination exactly disappears when the DP of L-and D-polypeptide are as close as possible [135].…”

Section: Achiral Oriented Systems By Compensationmentioning

confidence: 60%

“…Methods based on Nuclear Magnetic Resonance (NMR) spectroscopy [8] have also been explored for the determination of enantiomeric purity, since this technique provides unique insights into the atomiclevel structure and dynamics of gases, liquids and solids [8,9,10,11,12,13,14,15]. In a strong magnetic field, precessing nuclear spins in chiral molecules in an isotropic liquid induce a rotating electric polarization of opposite signs for enantiomers [16,17,18]. Alternatively, an applied electric field should also induce distinct NMR signals for enantiomers in an isotropic liquid [19].…”

Section: General Introductionmentioning

confidence: 99%

Multinuclear NMR in polypeptide liquid crystals: Three fertile decades of methodological developments and analytical challenges

Lesot

Aroulanda

Berdagué

et al. 2020

Progress in Nuclear Magnetic Resonance Spectroscopy

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NMR spectroscopy of oriented samples makes accessible residual anisotropic intramolecular NMR interactions, such as chemical shift anisotropy (RCSA), dipolar coupling (RDC), and quadrupolar coupling (RQC), while preserving high spectral resolution. In addition, in a chiral aligned environment, enantiomers of chiral molecules or enantiopic elements of prochiral compounds adopt different average orientations on the NMR timescale, and hence produce distinct NMR spectra or signals. NMR spectroscopy in chiral aligned media is a powerful analytical tool, and notably provides unique information on (pro)chirality analysis, natural isotopic fractionation, stereochemistry, as well as molecular conformation and configuration. Significant progress has been made in this area over the three last decades, particularly using polypeptide-based chiral liquid crystals (CLCs) made of organic solutions of helically chiral polymers (as PBLG) in organic solvents. This review presents an overview of NMR in polymeric LCs. In particular, we describe the theoretical tools and the major NMR methods that have been developed and applied to study (pro)chiral molecules dissolved in such oriented solvents. We also discuss the representative applications illustrating the analytical potential of this original NMR tool. This overview article is dedicated to thirty years of original contributions to the development of NMR spectroscopy in polypeptide-based chiral liquid crystals.

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“…Buckingham [333,334] emphasized that additional terms are to be added to the expression for the electric polarization, equations (111) and (112), to account for the contribution of the magnetic shielding tensor of nucleus J to the mean component of the permanent molecular electric dipole µ (0) , i.e.…”

Section: Contribution Of Molecular Electric Dipole and Antisymmetric ...mentioning

confidence: 99%

Chiral discrimination in nuclear magnetic resonance spectroscopy

Lazzeretti

2017

J. Phys.: Condens. Matter

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Chirality is a fundamental property of molecules whose spatial symmetry is characterized by the absence of improper rotations, making them not superimposable to their mirror image. Chiral molecules constitute the elementary building blocks of living species and one enantiomer is favoured in general (e.g. L-aminoacids and D-sugars pervade terrestrial homochiral biochemistry) because most chemical reactions producing natural substances are enantioselective. Since the effect of chiral chemicals and drugs on living beings can be markedly different between enantiomers, the quest for practical spectroscopical methods to scrutinize chirality is an issue of great importance and interest. Nuclear magnetic resonance (NMR) is a topmost analytical technique, but spectrometers currently used are 'blind' to chirality, i.e. unable to discriminate the two mirror-image forms of a chiral molecule, because, in the absence of a chiral solvent, the spectral parameters, chemical shifts and spin-spin coupling constants are identical for enantiomers. Therefore, the development of new procedures for routine chiral recognition would offer basic support to scientists. However, in the presence of magnetic fields, a distinction between true and false chirality is mandatory. The former epitomizes natural optical activity, which is rationalized by a time-even pseudoscalar, i.e. the trace of a second-rank tensor, the mixed electric dipole/magnetic dipole polarizability. The Faraday effect, magnetic circular dichroism and magnetic optical activity are instead related to a time-odd axial vector. The present review summarizes recent theoretical and experimental efforts to discriminate enantiomers via NMR spectroscopy, with the focus on the deep connection between chirality and symmetry properties under the combined set of fundamental discrete operations, namely charge conjugation, parity (space inversion) and time (motion) reversal.

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Chiral discrimination in NMR spectroscopy

Cited by 7 publications

References 11 publications

Influence of Magnetic Field on the Mobility of Aromatic Chiral Molecules

Influence of Magnetic Field on the Mobility of Aromatic Chiral Molecules

Multinuclear NMR in polypeptide liquid crystals: Three fertile decades of methodological developments and analytical challenges

Chiral discrimination in nuclear magnetic resonance spectroscopy

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