Measuring Amide Nitrogen Quadrupolar Coupling by High-Resolution14N/13C NMR Correlation under Magic-Angle Spinning

2006 ◽  
Vol 128 (18) ◽  
pp. 6040-6041 ◽  
Author(s):  
Zhehong Gan
Keyword(s):  
13C Nmr ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Amide Nitrogen ◽  
Quadrupolar Coupling ◽  
Angle Spinning

scholarly journals Single-Crystal 31P and 7Li NMR of the Ionic Conductor LiH2PO4

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 302
Author(s):  
Otto E. O. Zeman ◽  
Viktoria Kainz ◽  
Thomas Bräuniger
Keyword(s):  
Single Crystal ◽  
Rotation Axis ◽  
Polycrystalline Sample ◽  
Magic Angle Spinning ◽  
Ionic Conductor ◽  
Dihydrogen Phosphate ◽  
Magic Angle ◽  
Orthorhombic Crystal ◽  
Quadrupolar Coupling ◽  
Angle Spinning

The electronic surroundings of phosphorus and lithium atoms in the ionic conductor lithium dihydrogen phosphate (LDP) have been studied by single-crystal nuclear magnetic resonance (NMR) spectroscopy at room temperature. From orientation-dependent NMR spectra of a large homegrown LDP single crystal, the full 31P chemical shift (CS) and 7Li quadrupole coupling (QC) tensor was determined, using a global fit over three rotation patterns. The resulting CS tensor is characterized by its three eigenvalues: δ 11 P A S = ( 67.0 ± 0.6 ) ppm, δ 22 P A S = ( 13.9 ± 1.5 ) ppm, and δ 33 P A S = ( − 78.7 ± 0.9 ) ppm. All eigenvalues have also been verified by magic-angle spinning NMR on a polycrystalline sample, using Herzfeld–Berger analysis of the rotational side band pattern. The resulting 7Li QC tensor is characterized by its quadrupolar coupling constant χ = Q 33 P A S = ( − 71 ± 1 ) kHz and the two eigenvalues Q 11 P A S = ( 22.3 ± 0.9 ) kHz, and Q 22 P A S = ( 48.4 ± 0.8 ) kHz. The initially unknown orientation of the mounted crystal, expressed by the orientation of the rotation axis in the orthorhombic crystal frame, was included in the global data fit as well, thus obtaining it from NMR data only.

Solid State 13C NMR Applied to Styrene-Butadiene Rubbers Study of the Rubber Vulcanized Network Structures

2002 ◽  
Vol 75 (1) ◽  
pp. 65-76 ◽  
Author(s):  
L. Pellicioli ◽  
S. K. Mowdood ◽  
F. Negroni ◽  
D. D. Parker ◽  
J. L. Koenig
Keyword(s):  
13C Nmr ◽  
Structural Changes ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Nmr Spectrum ◽  
Polymer Microstructure ◽  
Polybutadiene Rubber ◽  
Angle Spinning ◽  
Styrene Butadiene

Abstract This paper discusses the structural changes that occur during the accelerated sulfur vulcanization of styrene-butadiene rubbers (SBR) through characterization of the network sulfide structures influenced by the curing agent concentration, the polymer microstructure, and the nature of the filler. Magic angle spinning (MAS) 13C FT - NMR spectroscopy was used to investigate the chemical crosslink properties of unfilled vulcanized SBR in addition to carbon black and silica filled polybutadiene rubber (BR), SBR, and 1:1 BR / SBR blends. New resonances in the 13C NMR spectrum are assigned to the various sulfide crosslink structures in SBR. Structural changes during vulcanization are also discussed.

A magic angle spinning 13C NMR study of 13CO-labelled tricarbonyl(hexahapto-hexamethylbenzene)chromium(0) and tricarbonyl(hexahapto-durene)chromium(0)

Polyhedron ◽  
1995 ◽  
Vol 14 (19) ◽  
pp. 2691-2696
Author(s):  
John A. Chudek ◽  
Geoffrey Hunter ◽  
John D. Paton ◽  
Barbara A. Walmsley
Keyword(s):  
13C Nmr ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Nmr Study ◽  
Angle Spinning
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