Phosphorus-31 magic angle spinning NMR of crystalline phosphorus sulfides: correlation of phosphorus-31 chemical shielding tensors with local environments

1989 ◽  
Vol 93 (1) ◽  
pp. 452-457 ◽  
Author(s):  
Hellmut Eckert ◽  
Cheryl S. Liang ◽  
Galen D. Stucky
Keyword(s):  
Magic Angle Spinning ◽  
Magic Angle ◽  
Chemical Shielding ◽  
Local Environments ◽  
Shielding Tensors ◽  
Angle Spinning

Phosphorus-31 chemical shieldings in a fused cis-1,2,3-benzothiadiphosphole: a dipolar NMR study

1992 ◽  
Vol 70 (4) ◽  
pp. 1229-1235 ◽  
Author(s):  
Gang Wu ◽  
Roderick E. Wasylishen ◽  
William P. Power ◽  
Graziano Baccolini
Keyword(s):  
Line Shape ◽  
Magic Angle Spinning ◽  
Pair Approximation ◽  
Magic Angle ◽  
Single Bond ◽  
Chemical Shielding ◽  
Spin Pair ◽  
Nmr Study ◽  
Shielding Tensors ◽  
Angle Spinning

Phosphorus-31 NMR static powder spectra and high-resolution magic angle spinning spectra have been obtained for a new heterocyclic compound, cis-2,10-dimethyl[1,2,3]benzothiadiphospholo[2,3b][1,2,3]benzothiadiphosphole (1), which contains a P(III)—P(III) single bond. The homonuclear 31P–31P dipolar interaction manifests itself in both the magic angle spinning spectra and the non-spinning line shape. Under the AX spin pair approximation, analysis of the spinning sidebands in the MAS experiment yields a full characterization of the two 31P chemical shielding tensors. This approximation is confirmed by the exact powder line shape simulation for a homonuclear spin pair. Analysis of the dipolar subspectra also yields the absolute sign of 1J(P,P), which is found to be negative. Keywords: phosphorus–phosphorus single bond, chemical shielding tensors, dipolar NMR, MAS, static line shape.

A 13C and 15N nuclear magnetic resonance study of solid ammonium thiocyanate

1987 ◽  
Vol 65 (5) ◽  
pp. 941-946 ◽  
Author(s):  
Ross M. Dickson ◽  
Michael S. McKinnon ◽  
James F. Britten ◽  
Roderick E. Wasylishen
Keyword(s):  
Ammonium Thiocyanate ◽  
Nuclear Magnetic Resonance Study ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Chemical Shielding ◽  
X Ray ◽  
Shielding Constants ◽  
Angle Spinning ◽  
Good Agreement ◽  
C Nmr

The static 13C nmr powder pattern for solid ammonium thiocyanate is analyzed to obtain the 13C chemical shielding anisotropy, 321 ± 7 ppm, and the 13C–14N dipolar splitting, 1295 ± 25 Hz. Slow magic angle spinning 15N nmr experiments are analyzed to obtain a nitrogen chemical shielding anisotropy of 415 ± 15 ppm. The 13C–14N dipolar splitting leads to an effective C—N bond length of 1.19 ± 0.01 Å, in good agreement with the value of 1.176 Å reported from accurate X-ray and neutron crystallographic studies. In solid NH4NCS absolute values of the average shielding constants [Formula: see text] and ct[Formula: see text] are 52 and 34 ppm, respectively. Comparison of calculated and observed [Formula: see text] values indicates that intermolecular interactions decrease the 13C and 15N shielding constants by approximately 10 and 30 ppm, respectively.

Comparative Structural Study and Dissolution of Simplified Glasses: A Radioactive Waste Glass (R7T7) and a Basaltic Glass

1997 ◽  
Vol 506 ◽  
Author(s):  
F. Angeli ◽  
P. Faucon ◽  
T. Charpentier ◽  
J.C. Petit ◽  
J. Virlet
Keyword(s):  
Nuclear Waste ◽  
Magic Angle Spinning ◽  
Waste Glass ◽  
Magic Angle ◽  
Basaltic Glass ◽  
Qualitative Information ◽  
Local Environments ◽  
Nuclear Waste Glass ◽  
Angle Spinning ◽  
Main Components

ABSTRACTThe local cation environments in a borosilicate glass (containing the main components of the French nuclear waste glass, R7T7) and of basaltic-like glass are presented on the basis of17A1 and23Na Multi-Quanta Magic-Angle Spinning Nuclear Magnetic Resonance (MQ-MAS NMR) spectroscopies. The chemical and geometrical environment of each nucleus is characterized. Moreover, qualitative information about the distribution of these parameters, characteristic of the disorder level in the structure, is obtained. These results are presented with the characteristics of the Al and Na dissolution in water at 100°C. The relation between the local environments of these cations and their mass loss in solution is discussed.

Article

1999 ◽  
Vol 77 (11) ◽  
pp. 1962-1972
Author(s):  
Scott Kroeker ◽  
Roderick E Wasylishen
Keyword(s):  
Nmr Spectra ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Spin Coupling ◽  
Group Symmetry ◽  
Magic Angle ◽  
Chemical Shielding ◽  
Shielding Tensor ◽  
Angle Spinning ◽  
Spin Spin Coupling

Direct NMR observation of copper-63/65 nuclei in solid K3Cu(CN)4 provides the first experimental example of anisotropic copper chemical shielding. Axially symmetric by virtue of the space group symmetry, the shielding tensor spans 42 ppm, with the greatest shielding when the unique axis is perpendicular to the applied magnetic field. The nuclear quadrupole coupling constant is also appreciable, CQ(63Cu) = -1.125 MHz, reflecting a deviation of the Cu(CN)43- anion from pure tetrahedral symmetry. Spin-spin coupling to 13C nuclei in an isotopically enriched sample is quantified by line-shape simulations of both 13C and 63/65Cu magic-angle spinning (MAS) NMR spectra to be 300 Hz. It is shown that this information is also directly available by 63/65Cu triple-quantum (3Q) MAS NMR. The relative merits of these three approaches to characterizing spin-spin couplings involving half-integer quadrupolar nuclei are discussed. Chemical shielding tensors for nitrogen-15 and carbon-13 are obtained from NMR spectra of non-spinning samples, and are compared to those of tetrahedral group 12 tetracyanometallates. Finally, 2J(63/65Cu,15N) detected in 15N MAS experiments are found to be 19 and 20 Hz for the two crystallographically distinct cyanide ligands.Key words: NMR, quadrupolar nucleus, chemical shielding tensor, multiple-quantum magic-angle spinning, metal cyanide, spin-spin coupling.

scholarly journals Solid-state NMR measurements and DFT calculations of the magnetic shielding tensors of protons of water trapped in barium chlorate monohydrate

RSC Advances ◽  
2014 ◽  
Vol 4 (99) ◽  
pp. 56248-56258 ◽  
Author(s):  
Diego Carnevale ◽  
Sharon E. Ashbrook ◽  
Geoffrey Bodenhausen
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
Solid State Nmr ◽  
Magic Angle Spinning ◽  
Magnetic Shielding ◽  
Magic Angle ◽  
Solid State Nmr Spectroscopy ◽  
Shielding Tensors ◽  
Angle Spinning

The magnetic shielding tensors of protons of water in barium chlorate monohydrate are investigated by means of solid-state NMR spectroscopy, both for static powders and under magic-angle spinning conditions.

Nuclear magnetic shielding tensors for the carbon, nitrogen, and selenium nuclei of selenocyanates - a combined experimental and theoretical approach

2000 ◽  
Vol 78 (5) ◽  
pp. 614-625 ◽  
Author(s):  
Guy M Bernard ◽  
Klaus Eichele ◽  
Gang Wu ◽  
Christopher W Kirby ◽  
Roderick E Wasylishen
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Axially Symmetric ◽  
Paramagnetic Contribution ◽  
Shielding Tensors ◽  
The Difference ◽  
Shielding Tensor ◽  
Angle Spinning

The principal components of the carbon, nitrogen, and selenium chemical shift (CS) tensors for several solid selenocyanate salts have been determined by NMR measurements on stationary or slow magic-angle-spinning powder samples. Within experimental error, all three CS tensors are axially symmetric, consistent with the expected linear geometry of these anions. The spans (Ω) of the carbon and selenium CS tensors for the selenocyanate anion (SeCN-) are approximately 300 and 800 ppm, respectively, much less than the corresponding values for carbon diselenide (CSe2). This difference is a consequence of the difference in the CS tensor components perpendicular to the C infiniti symmetry axes in these systems. Ab initio calculations show that the orbital symmetries of these compounds are a significant factor in the shielding. For CSe2, efficient mixing of the σ and π orbitals results in a large paramagnetic contribution to the total shielding of the chemical shielding tensor components perpendicular to the molecular axis. Such mixing is less efficient for the SeCN-, resulting in a smaller paramagnetic contribution and hence in greater shielding in directions perpendicular to the molecular axis.Key words: selenocyanates, solid-state NMR, carbon shielding tensors, nitrogen shielding tensors, selenium shielding tensors, ab initio calculations.

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