Symmetrized Multipulse Nuclear-Magnetic-Resonance Experiments in Solids: Measurement of the Chemical-Shift Shielding Tensor in Some Compounds

1973 ◽  
Vol 7 (1) ◽  
pp. 90-105 ◽  
Author(s):  
P. Mansfield ◽  
M. J. Orchard ◽  
D. C. Stalker ◽  
K. H. B. Richards
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Shielding Tensor ◽  
Nuclear Magnetic

NUCLEAR MAGNETIC RESONANCE STUDIES: IX. THE CHEMICAL SHIFT OF THE FORMYL PROTON IN ALIPHATIC ALDEHYDES

1966 ◽  
Vol 44 (1) ◽  
pp. 45-51 ◽  
Author(s):  
R. E. Klinck ◽  
J. B. Stothers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Aliphatic Aldehydes ◽  
Magnetic Resonance Studies ◽  
Unsaturated Aldehydes ◽  
Potential Use ◽  
Nuclear Magnetic

The effects of structure on the shielding of formyl protons of aliphatic aldehydes have been examined. The survey included examples of acyclic, alicyclic, and α, β-unsaturated aldehydes. The potential use of these results as an aid for structural elucidations is discussed, and the limitations are noted.

scholarly journals Elucidating Tricin-Lignin Structures: Assigning Correlations in HSQC Spectra of Monocot Lignins

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 916 ◽  
Author(s):  
Wu Lan ◽  
Fengxia Yue ◽  
Jorge Rencoret ◽  
José del Río ◽  
Wout Boerjan ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Nmr Spectra ◽  
Model Compounds ◽  
Heteronuclear Correlation ◽  
Nmr Methods ◽  
Nuclear Magnetic ◽  
Lignin Structure

Tricin [5,7-dihydroxy-2-(4-hydroxy-3,5-dimethoxyphenyl)-4H-chromen-4-one] is a flavone that has been found to be incorporated in grass lignin polymers via 4′–O–β coupling. Herein, we investigated the tricin-lignin structure using nuclear magnetic resonance (NMR) methods by comparing the 1H–13C heteronuclear correlation (HSQC) NMR spectra of the isolated lignin with a series of dimeric and trimeric tricin-4′–O–β-ether model compounds. Results showed that the tricin moiety significantly affects the chemical shift of the Cβ/Hβ of 4′–O–β unit, producing peaks at around δC/δH 82.5–83.5/4.15–4.45, that differ from the Cβ/Hβ correlations from normal 4–O–β units formed solely by monolignols, and that have to date been unassigned.

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