Nuclear magnetic shielding and chirality. II. The shielding tensor of a naked spin in Ne helices

2003 ◽  
Vol 119 (5) ◽  
pp. 2691-2693 ◽  
Author(s):  
Devin N. Sears ◽  
Cynthia J. Jameson ◽  
Robert A. Harris
Keyword(s):  
Magnetic Shielding ◽  
Shielding Tensor ◽  
Nuclear Magnetic

Probing solid iminobis(diorganophosphine chalcogenide) systems with multinuclear magnetic resonance

2009 ◽  
Vol 87 (1) ◽  
pp. 348-360 ◽  
Author(s):  
Bryan A Demko ◽  
Roderick E Wasylishen
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Solid State Nmr ◽  
Magnetic Shielding ◽  
Chemical Shift Tensors ◽  
X Ray ◽  
X Ray Crystallography ◽  
Shielding Tensor ◽  
Nuclear Magnetic Shielding Tensors ◽  
Nuclear Magnetic

A 31P and 77Se solid-state NMR investigation of the iminobis(diorganophosphine chalcogenide) HN(R2PE)2 (R = Ph,iPr; E = O, S, Se) systems is presented. The NMR results are discussed in terms of the known HN(R2PE)2 structures available from X-ray crystallography. The phosphorus chemical shift tensors are found to be sensitive to the nature of the alkyl and chalcogen substituents. The nature of the R group also influences the selenium chemical shift tensors of HN(R2PSe)2 (R = Ph, iPr), which are shown to be sensitive to hydrogen bonding in the dimer structure of HN(Ph2PSe)2 and to the presence of disorder in the case of HN(iPr2PSe)2. Scalar relativistic ZORA DFT nuclear magnetic shielding tensor calculations were performed yielding the orientations of the corresponding chemical shift tensors. A theoretical investigation into the effect of the E-P···P-E “torsion” angle on the phosphorus and selenium chemical shift tensors of a truncated HN(Me2PSe)2 system indicates that the electronic effect of the alkyl group on the respective nuclear magnetic shielding tensors are more important than the steric effect of the E-P···P-E torsion angle.Key words: iminobis(diorganophosphine chalcogenide), solid-state NMR, 31P NMR, 77Se NMR, ZORA DFT.

Nuclear magnetic shielding and chirality. I. The shielding tensor of Xe interacting with Ne helices

2003 ◽  
Vol 119 (5) ◽  
pp. 2685-2690 ◽  
Author(s):  
Devin N. Sears ◽  
Cynthia J. Jameson ◽  
Robert A. Harris
Keyword(s):  
Magnetic Shielding ◽  
Shielding Tensor ◽  
Nuclear Magnetic

Isotropie and Anisotropie Nuclear Magnetic Shielding of 113Cd in Cadmiumhalides, Cadmiumchalcogenides and in Cadmiumcarbonate

1978 ◽  
Vol 33 (6) ◽  
pp. 666-671 ◽  
Author(s):  
A. Nolle
Keyword(s):  
The Other ◽  
Magnetic Shielding ◽  
Axially Symmetric ◽  
Reference Scale ◽  
Cadmium Chalcogenides ◽  
Shielding Constants ◽  
Powder Samples ◽  
Shielding Tensor ◽  
Nmr Signals ◽  
Nuclear Magnetic

Abstract The NMR signals of 113Cd have been observed in powder samples of the cadmium halides CdF2, CdCl2, CdBr2· 4H2O, Cdl2, of the cadmium chalcogenides CdO, CdS, CdSe, CdTe and of CdCO3 . For 113Cd in CdCl2 , CdBr2-4H2O, CdS and in CdSe anisotropics of the nuclear magnetic shielding have been detected. The shielding tensor in these powders is axially symmetric. For the other specimens no anisotropics of the magnetic shielding have been found. The principal values of the magnetic shielding tensor and the shielding constants are given in an atomic reference scale.

19F nuclear magnetic shielding tensor of CH3F

1995 ◽  
Vol 86 (2) ◽  
pp. 235-249 ◽  
Author(s):  
Thomas Enevoldsen ◽  
Jens Oddershede
Keyword(s):  
Magnetic Shielding ◽  
Shielding Tensor ◽  
Nuclear Magnetic

scholarly journals Recent Advances in Theoretical and Physical Aspects of NMR Chemical Shifts

KIMIKA ◽  
2015 ◽  
Vol 26 (2) ◽  
pp. 1-30 ◽  
Author(s):  
Angel C. De Dios ◽  
Cynthia Juan Jameson
Keyword(s):  
Ab Initio ◽  
Relativistic Theory ◽  
Chemical Shifts ◽  
Open Shell ◽  
Magnetic Shielding ◽  
Theoretical Treatment ◽  
Rotation Tensor ◽  
Nuclear Shielding ◽  
Shielding Tensor ◽  
Nuclear Magnetic

In the first part of this review, theoretical aspects of nuclear magnetic shielding include (a) general theory, for example, newly developed approaches in relativistic theory of nuclear shielding, the relation between the spin-rotation tensor and shielding in relativistic theory, ab initio methods for treating open shell systems and a complete theory of chemical shifts in paramagnetic systems, the link between the definitions of the elusive concepts aromaticity and anti-aromaticity and the magnetic properties: the magnetizability tensor and the nuclear magnetic shielding tensor via delocalized electron currents and electron current maps, (b) ab initio and DFT calculations, both relativistic and non-relativistic, for various nuclei in various molecular systems using various levels of theoretical treatment. Physical aspects include (a) anisotropy of the shielding tensor, usually from solid state measurements, and calculations to support these, (b) shielding surfaces and rovibrational averaging, paying special attention to the sensitive relationship between shielding and bond angles or torsion angles that makes shielding such a powerful tool for structural/conformational determination in macromolecules, (c) chemical shifts that arise from isotopic substitution of NMR nucleus or neighboring nuclei, (d) intermolecular effects on nuclear shielding, and (e) absolute shielding scales.

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