ChemInform Abstract: Magnitudes and Relative Orientation of 51V Quadrupole Coupling and Anisotropic Shielding Tensors in Metavanadates and KV3O8 from 51V MAS NMR Spectra. 23Na Quadrupole Coupling Parameters for α- and . beta.-NaVO3.

ChemInform ◽  
2010 ◽  
Vol 24 (48) ◽  
pp. no-no
Author(s):  
J. SKIBSTED ◽  
N. CHR. NIELSEN ◽  
H. BILDSOEE ◽  
H. J. JAKOBSEN
Keyword(s):  
Nmr Spectra ◽  
Relative Orientation ◽  
Mas Nmr ◽  
Quadrupole Coupling ◽  
Coupling Parameters ◽  
Shielding Tensors

scholarly journals On the preparation and NMR spectroscopic characterization of potassium aluminium tetrahydride KAlH4

2019 ◽  
Vol 21 (23) ◽  
pp. 12576-12584 ◽  
Author(s):  
Bodo Zibrowius ◽  
Michael Felderhoff
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Spectroscopic Characterization ◽  
Mas Nmr ◽  
Isotropic Chemical Shift ◽  
Quadrupole Coupling ◽  
Coupling Parameters

Conventional 1D 27Al MAS NMR spectroscopy allows the isotropic chemical shift and the quadrupole coupling parameters of Pnma KAlH4 to be determined precisely.

Characterization of phosphorus chemical shielding tensors in a phosphole tetramer: a combined experimental and theoretical study

2000 ◽  
Vol 78 (1) ◽  
pp. 118-127 ◽  
Author(s):  
Myrlene Gee ◽  
Roderick E Wasylishen ◽  
Klaus Eichele ◽  
Gang Wu ◽  
T Stanley Cameron ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Nmr Spectra ◽  
Spin Echo ◽  
Relative Orientation ◽  
Chemical Shielding ◽  
Spin Pair ◽  
Shielding Tensors ◽  
Shielding Tensor ◽  
Spin Pairs

Phosphorus-31 1D NMR spectra of a stationary powder sample of a phosphole tetramer containing two phosphorus spin pairs have been obtained at 4.7 T and 9.4 T. In order to separate 31P-31P spin-spin coupling from anisotropic chemical shielding, 2D spin-echo NMR spectra have been acquired. Phosphorus-31 CPMAS NMR experiments indicate that the two spin pairs of the tetramer are equivalent and each may be treated as an isolated spin pair. Within a given spin pair, the difference between the isotropic chemical shifts of two directly bonded phosphorus nuclei is 1.7 ppm. As well, they are spin-spin coupled by both the indirect and direct interactions, 1J(31P, 31P) = -362 Hz and RDD = 1.80 kHz, respectively. The principal components and relative orientation of the two phosphorus chemical shielding tensors have been determined using the dipolar-chemical shift technique; however, since the dipolar tensor is axially symmetric, ambiguities in the chemical shielding tensor orientation relative to the molecular framework result. Using ab initio calculations and simulations of the 2D spin-echo spectra, many of these ambiguities have been resolved. The spans and skews of the phosphorus shielding tensors for all four three-coordinate phosphorus nuclei are the same within experimental error, 115 ppm and 0.70, respectively. Combined experimental and theoretical results indicate that the phosphorus shielding tensor orientations are dictated by the local environment. For both shielding tensors, the most shielded component, δ33, is approximately 78° from the P-P bond and in the phosphole ring plane. The relative orientation of the δ33 components is described by a dihedral angle of 82°, similar to the dihedral angle of approximately 76° defining the twist of the phosphole rings about the bridging P-P bond.Key words: solid-state 31P NMR, phosphorus chemical shielding tensors, phosphole tetramer, 31P—31P spin pairs, ab initio calculations.

scholarly journals Sensitivity gains, linearity, and spectral reproducibility in nonuniformly sampled multidimensional MAS NMR spectra of high dynamic range

2014 ◽  
Vol 59 (2) ◽  
pp. 57-73 ◽  
Author(s):  
Christopher L. Suiter ◽  
Sivakumar Paramasivam ◽  
Guangjin Hou ◽  
Shangjin Sun ◽  
David Rice ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Mas Nmr ◽  
High Dynamic

Hydration effects in the carbon-13 CP/MAS NMR spectra of solid (1 →3)-β-D-glucans

1984 ◽  
Vol 17 (3) ◽  
pp. 501-502 ◽  
Author(s):  
C. A. Fyfe ◽  
P. J. Stephenson ◽  
M. G. Taylor ◽  
T. L. Bluhm ◽  
Y. Deslandes ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Mas Nmr ◽  
Cp Mas Nmr

scholarly journals Shared and unique metabolic features of the malignant and benign thyroid lesions determined with use of 1H HR MAS NMR spectroscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agnieszka Skorupa ◽  
Mateusz Ciszek ◽  
Ewa Chmielik ◽  
Łukasz Boguszewicz ◽  
Małgorzata Oczko-Wojciechowska ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Univariate Analysis ◽  
Mas Nmr ◽  
Metabolic Reprogramming ◽  
Benign Lesions ◽  
Chronic Thyroiditis ◽  
Malignant Lesions ◽  
Metabolic Heterogeneity ◽  
Benign Thyroid ◽  
Thyroid Lesions

AbstractThe purpose of this work was to investigate the distinct and common metabolic features of the malignant and benign thyroid lesions in reference to the non-transformed tissue from the contralateral gland (chronic thyroiditis and colloid goiter). 1H HR MAS NMR spectra of 38 malignant lesions, 32 benign lesions and 112 samples from the non-tumoral tissue (32 from chronic thyroiditis and 80 samples from colloid goiter) were subjected both to multivariate and univariate analysis. The increased succinate, glutamine, glutathione, serine/cysteine, ascorbate, lactate, taurine, threonine, glycine, phosphocholine/glycerophosphocholine and decreased lipids were found in both lesion types in comparison to either colloid goiter or chronic thyroiditis. The elevated glutamate and choline, and reduced citrate and glucose were additionally evident in these lesions in reference to goiter, while the increased myo-inositol—in comparison to thyroiditis. The malignant lesions were characterized by the higher alanine and lysine levels than colloid goiter and thyroiditis, while scyllo-inositol was uniquely increased in the benign lesions (not in cancer) in comparison to both non-tumoral tissue types. Moreover, the benign lesions presented with the unique increase of choline in reference to thyroiditis (not observed in the cancerous tissue). The metabolic heterogeneity of the non-tumoral tissue should be considered in the analysis of metabolic reprogramming in the thyroid lesions.

Structural Characterization of Glass from the Inversion of23Na and27Al 3Q-MAS NMR Spectra

1999 ◽  
Vol 103 (47) ◽  
pp. 10356-10364 ◽  
Author(s):  
F. Angeli ◽  
T. Charpentier ◽  
P. Faucon ◽  
J.-C. Petit
Keyword(s):  
Structural Characterization ◽  
Nmr Spectra ◽  
Mas Nmr
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