Nuclear magnetic resonance in an anti ferromagnetic single crystal. Part I

Poulis, N.J.; Hardeman, G.E.G.

doi:10.1016/s0031-8914(52)80145-4

Cited by 116 publications

(22 citation statements)

References 1 publication

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“…Significant paramagnetic shift effects have been observed in 1 H NMR spectra of CuCl 2 •2H 2 O ͑where Cu 2ϩ has a single unpaired electron in a 3d orbital͒ 12,38 and, therefore, we selected the deuterated analog, CuCl 2 •2D 2 O, as a suitable model for the study of 2 H paramagnetic shift interactions. A single crystallographically distinct 2 H site 39,40 results in a single resonance with an isotropic chemical shift of ␦ iso ϭ75.3Ϯ0.5 ppm in the 2 H MAS NMR spectrum ͑not shown͒.…”

Section: B Copper"ii… Chloride Dihydrate-d 4 "Cucl 2 "2d 2 O…mentioning

confidence: 99%

Separation of quadrupolar and chemical/paramagnetic shift interactions in two-dimensional H2 (I=1) nuclear magnetic resonance spectroscopy

Antonijevic

Wimperis

2005

The Journal of Chemical Physics

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A novel two-dimensional (2)H (spin I=1) nuclear magnetic resonance technique is introduced for determination of both quadrupole and chemical/paramagnetic shift tensors and their relative orientation. The new method is based upon the well-known quadrupolar-echo experiment and is designed to refocus the quadrupolar interaction at the end of the t(1) evolution period while retaining the modulation introduced by the shift interaction. As a result, a projection of the resulting two-dimensional spectrum onto its F(1) dimension yields a shift anisotropy powder lineshape free from any quadrupolar broadening. The chemical/paramagnetic shifts appear in both F(1) and F(2) dimensions and are thus spread along a +1 frequency gradient; hence, a projection orthogonal to this gradient yields the pure quadrupolar powder lineshape, free from all shift interaction effects. The relative orientation of the quadrupole and shift tensors can be obtained by analysis of the full two-dimensional correlation lineshape. Unlike the well-known double-quantum experiment, the new method is, in principle, equally effective for all values of the quadrupolar splitting, including zero. The properties of the new technique are demonstrated using computer simulation and methods for the extraction of quadrupole and shift tensor parameters are described. The new technique is applied to (diamagnetic) benzoic acid-d(1) (C(6)H(5)CO(2)D) and (paramagnetic) copper(II) chloride dihydrate-d(4) (CuCl(2).2D(2)O).

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Section: B Copper"ii… Chloride Dihydrate-d 4 "Cucl 2 "2d 2 O…mentioning

confidence: 99%

Separation of quadrupolar and chemical/paramagnetic shift interactions in two-dimensional H2 (I=1) nuclear magnetic resonance spectroscopy

Antonijevic

Wimperis

2005

The Journal of Chemical Physics

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“…7b). 34 The spins of the Cu 2+ ions are aligned along the Cu-O direction, 35 namely, the Cu  has the smallest energy gap with the HOMO, xz (Fig. 7b).…”

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confidence: 99%

Prediction of Spin Orientations in Terms of HOMO–LUMO Interactions Using Spin–Orbit Coupling as Perturbation

et al. 2015

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ConspectusFor most chemists and physicists, electron spin is merely a means needed to satisfy the Pauli principle in electronic structure description. However, the absolute orientations of spins in coordinate space can be crucial in understanding the magnetic properties of materials with unpaired electrons. At a low temperature the spins of a magnetic solid may undergo a long-range magnetic ordering, which allows one to determine the directions and magnitudes of spin moments by neutron diffraction refinements. The preferred spin orientation of a magnetic ion can be predicted on the basis of density functional theory (DFT) calculations including electron correlation and spin-orbit coupling (SOC). However, most chemists and physicists are unaware of how the observed and/or calculated spin orientations are related to the local electronic structures of the magnetic ions. This is true even for most crystallographers who determine the directions and magnitudes of spin moments because, for them, they are merely the parameters needed for the diffraction refinements. The objective of this article is to provide a conceptual framework of thinking about and predicting the preferred spin orientation of a magnetic ion by examining the relationship between the spin orientation and the local electronic structure of the ion. In general, a magnetic ion M (i.e., an ion possessing unpaired spins) in a solid or a molecule is surrounded with main-group ligand atoms L to form an MLn polyhedron, where n is typically 2 -6, and the d-states

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“…[1][2][3][4][5][6] The electron and nuclear spins may interact via dipole-dipole and/or Fermi contact interactions. The dipolar interaction depends on the separation of the electron and nuclear spins (r,) and the angle between the vector connecting the spins and the external magnetic field (4).…”

Section: Introductionmentioning

confidence: 99%

Low temperature NMR investigations of a series of polycrystalline metalloporphyrins

Sandreczki¹,

Ondercin²,

Kreilick³

1979

J. Phys. Chem.

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This paper reports low temperature NMR investigations of a series of polycrystalline metalloporphyrins. The NMR signals from ligand nuclei are shifted by dipole-dipole and Fermi contact interactions with the unpaired electron spin(s) of the transition metal ion. In favorable instances one is able to completely analyze the spectra to obtain dipolar and Fermi coupling constants. The dipolar coupling constant can be further analyzed to yield effective electron-nuclei distances. The NMR shifts vary with the magnetic susceptibility of the sample and the NMR spectra can be used to monitor the temperature dependence of the magnetic susceptibility. This paper reports results from NMR studies of silver tetraphenylporphyrin (AgTPP), CuTPP, CoTPP, and VOTPP as well as copper protoporphyrin IX (Cu(PP-1x1) and Fe(PP-1X)Cl (hemin). IntroductionNMR spectra of solid transition metal complexes taken at very low temperatures can provide information about the interaction of the metals' unpaired electron spin(s) with nuclei in the surrounding ligands.1-6 The electron and nuclear spins may interact via dipole-dipole and/or Fermi contact interactions. The dipolar interaction depends on

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Nuclear magnetic resonance in an anti ferromagnetic single crystal. Part I

Cited by 116 publications

References 1 publication

Separation of quadrupolar and chemical/paramagnetic shift interactions in two-dimensional H2 (I=1) nuclear magnetic resonance spectroscopy

Separation of quadrupolar and chemical/paramagnetic shift interactions in two-dimensional H2 (I=1) nuclear magnetic resonance spectroscopy

Prediction of Spin Orientations in Terms of HOMO–LUMO Interactions Using Spin–Orbit Coupling as Perturbation

Low temperature NMR investigations of a series of polycrystalline metalloporphyrins

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