High-Resolution Nuclear Magnetic Resonance Spectra of Orientated Molecules

Saupe, A.; Englert, Gerhard

doi:10.1103/physrevlett.11.462

Cited by 418 publications

(260 citation statements)

References 3 publications

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“…(2)) also leads to a torque on the molecule in a magnetic field, but unlike the antisymmetric part which gives partial orientation, it contributes to the alignment of the molecules (i.e., a non-zero value of 3cos 2 θ − 1 /2, where θ is the angle between the molecular z-axis and the magnetic field) and this will contribute to the birefringence proportional to the square of the magnetic field strength, that is, to the Cotton Mouton effect, as well as to the presence of direct nuclear spin dipole-dipole coupling in NMR spectra. 16 However, computations of the anisotropy of the shielding tensor for the H and F nuclei and of the molecular magnetizability of the hydrogen fluoride molecule by Ås-trand and Mikkelsen 17 indicate that the nuclear contribution to the alignment is only of the order of 10 −6 that arising from the magnetizability. However, this alignment contribution could be significant if the anisotropy of the magnetizability is small and if there are a large number of nuclei with non-zero spin or if the nuclear spins are strongly polarized.…”

Section: Discussionmentioning

confidence: 99%

Communication: Permanent dipoles contribute to electric polarization in chiral NMR spectra

Buckingham¹

2014

The Journal of Chemical Physics

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Nuclear magnetic resonance spectroscopy is blind to chirality because the spectra of a molecule and its mirror image are identical unless the environment is chiral. However, precessing nuclear magnetic moments in chiral molecules in a strong magnetic field induce an electric polarization through the nuclear magnetic shielding polarizability. This effect is equal and opposite for a molecule and its mirror image but is small and has not yet been observed. It is shown that the permanent electric dipole moment of a chiral molecule is partially oriented through the antisymmetric part of the nuclear magnetic shielding tensor, causing the electric dipole to precess with the nuclear magnetic moment and producing a much larger temperature-dependent electric polarization with better prospects of detection. © 2014 AIP Publishing LLC. [http://dx

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Section: Discussionmentioning

confidence: 99%

Communication: Permanent dipoles contribute to electric polarization in chiral NMR spectra

Buckingham¹

2014

The Journal of Chemical Physics

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“…Residual dipolar couplings (RDCs) have been observed as early as 1963 (Saupe & Englert, 1963) in nematic environments. A number of recent applications (Al-Hashimi & Patel, 2002;Bax et al, 2001;Blackledge, 2005;de Alba & Tjandra, 2002;Prestegard et al, 2000;Tolman, 2001;Zhou et al, 1999) have reignited their wide use in application to a broad spectrum of biomolecules.…”

Section: Residual Dipolar Couplings (Rdcs)mentioning

confidence: 99%

“…Rotation of the molecule within this frame is consequential in the representation of its order tensor while any translation in space is not. Alignment properties of a molecule can be described in the form of a Saupe order tensor matrix (Saupe & Englert, 1963;Valafar & Prestegard, 2004). Reformulation of Equation 1 in the matrix form collects and defines the Saupe order tensor matrix (or OTM for short) as represented by S in Equation 2.…”

Section: Molecular Frame Alignment Frame and Order Tensormentioning

confidence: 99%

Structure and Dynamics of Proteins from Nuclear Magnetic Resonance Spectroscopy

Valafar¹,

Irausquin²

2012

Protein Structure

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“…Residual dipolar couplings were first measured in solution by NMR in the 1960s 6,7 and were found to be an informationrich NMR structural parameter. These early studies focused on organic liquid crystals and produced very large dipolar couplings, which proved difficult to analyze.…”

Section: History Of Rdcsmentioning

confidence: 99%

Application of residual dipolar couplings in organic compounds

Yan¹,

Zartler²

2004

Magnetic Reson in Chemistry

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INTRODUCTIONThe classic NMR strategy for determining the structure or stereochemistry of small molecules is by using a combination of nuclear overhauser effect (NOE) and scalar J couplings. dependence, where r is the internuclear distance and can be used to connect protons up to 5Å apart. 2 1 H-1 H NOEs have the most utility in small-molecule studies. H-X NOEs usually require isotopic labeling, which can be difficult synthetically for small molecules.1 H-1 H scalar couplings are easy to measure and have high information content; 3 J HH leads to the relative orientations of the atoms by sequential connectivity and estimation of dihedral angles through the well-known Karplus equation.3 Long-range heteronuclear J couplings ( >2 J XH ) are also useful for structural determinations but the data are more difficult to obtain. Typically, these involve 13 C or 15 N as the X-nucleus and if the sample is not isotopically enriched the experiment, such as heteronuclear multiple bond coherence spectroscopy (HMBC), 4,5 can be very time consuming. If the molecule of interest has an overall dearth of protons, has NOEs that cannot be assigned unambiguously or has breaks in the NOE or scalar connectivities, the typical NOE/J analysis fails. Additionally, in order to obtain the relative orientation of remote centers, multiple NOE or J-coupling connections have to be performed in series to transverse the entire molecule. The further away the stereocenters are from each other, the greater the number of necessary connections and measurements needed to confirm unambiguously the connectivity. If one of the connections fails, the pathway fails. Thus, a method that does not rely upon these connectivities would be extremely useful for stereochemistry

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High-Resolution Nuclear Magnetic Resonance Spectra of Orientated Molecules

Cited by 418 publications

References 3 publications

Communication: Permanent dipoles contribute to electric polarization in chiral NMR spectra

Communication: Permanent dipoles contribute to electric polarization in chiral NMR spectra

Structure and Dynamics of Proteins from Nuclear Magnetic Resonance Spectroscopy

Application of residual dipolar couplings in organic compounds

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