PMR spectra of triglycerides: discrimination of isomers with the aid of a chemical shift reagent

1972 ◽  
Vol 13 (25) ◽  
pp. 2533-2536 ◽  
Author(s):  
P.E. Pfeffer ◽  
H.L. Rothbart
Keyword(s):  
Chemical Shift ◽  
Shift Reagent ◽  
Pmr Spectra

scholarly journals PMR Spectra of Poly(methyl vinyl ether) in the Presence of Shift Reagent

1972 ◽  
Vol 3 (5) ◽  
pp. 645-646 ◽  
Author(s):  
Heimei Yuki ◽  
Koichi Hatada ◽  
Toshihiko Hasegawa ◽  
Yoshio Terawaki ◽  
Hiroshi Okuda
Keyword(s):  
Vinyl Ether ◽  
Shift Reagent ◽  
Methyl Vinyl ◽  
Pmr Spectra ◽  
Methyl Vinyl Ether

scholarly journals The use of tris (tetraphenylimidodiphosphinate) of praseodymium chemical shift reagent in proton NMR for the evaluation of the argan oil fatty acids autoxidation and the analysis of the argan pulp fatty acids

2019 ◽  
Vol 8 (2) ◽  
pp. 115-131
Author(s):  
Souad Hamdouch ◽  
Latifa Barkaoui ◽  
Merriem Tarbaoui ◽  
Amine Ouaket
Keyword(s):  
Fatty Acids ◽  
Chemical Shift ◽  
Unsaturated Fatty Acids ◽  
Proton Nmr ◽  
Oil Extraction ◽  
Shift Reagent ◽  
Complex Molecules ◽  
Nmr Method ◽  
Molecular Investigation ◽  
The One

Proton NMR is a method of molecular investigation that has its limitations when applied to complex molecules or molecules with many nearly equivalent sites. Previous studies have resorted to the use of paramagnetic chemical shift reagents, having as formula tris (tetraphenylimidodiphosphinate) of lanthanides ln((tpip.)3. The use of reagent Pr(tpip)3 in proton RMN has allowed us to evaluate the autoxidation of fatty acids mixture (stored 6 and 12 months after oil extraction) by the dosage of saturated and unsaturated acids on the one hand, and that of oleic and linoleic acids on the other. We note between 6 and 12 months of storage at 4°C a decrease in the percentage of unsaturated acids (76% to 63%) and an increase in the percentage of saturated acids (24% to 36%). The results show that the oleic acid maintained the same percentage (35%) as it is not easily oxidized whereas, for the linoleic acid, we observe a decrease in percentage from 22.5% to 18.5% (slow autoxidation at 4°C). We also used this NMR method for the analysis of the argan pulp fatty part. The GC analysis shows that it contains very few unsaturated fatty acids and that the main fatty acids are myristic (C14:0) and palmitic (C16:0) acids. The proton NMR with Pr(tpip)3 allowed us to confirm these results. This method that does not require derivation has proven to be interesting, simple and efficient.

Quantum Chemical Systematization of the PMR Spectra of Some N-(Pyridyl)-pyrrole Derivatives

1975 ◽  
Vol 30 (9-10) ◽  
pp. 784-787 ◽  
Author(s):  
P. Dvortsák ◽  
G. Náray-Szabó ◽  
L. Vasvári-Debreczy
Keyword(s):  
Chemical Shift ◽  
Charge Distribution ◽  
Linear Relation ◽  
Quantum Chemical ◽  
Chemical Shifts ◽  
Steric Effects ◽  
Pyrrole Derivatives ◽  
Pmr Spectra ◽  
Net Charges

In the case of a number of N-(pyridyl)-pyrrole derivatives a linear relation was found between the PMR chemical shifts of the olefinic and aromatic protons and the adjacent carbon net charges. The charge distribution was obtained as a sum of σ- and π-parts, calculated by the Del Re and PPP methods, respectively. Steric effects were treated on the basis of chemical shift anomalies.

NMR spectra of thiolsulfinates containing heterosteric groups. Use of a chemical shift reagent

1972 ◽  
Vol 13 (37) ◽  
pp. 3907-3910 ◽  
Author(s):  
Larry E. Legler ◽  
Sohan L. Jindal ◽  
Robert W. Murray
Keyword(s):  
Chemical Shift ◽  
Nmr Spectra ◽  
Shift Reagent

scholarly journals Increasing the Chemical-Shift Dispersion of Unstructured Proteins with a Covalent Lanthanide Shift Reagent

2016 ◽  
Vol 55 (47) ◽  
pp. 14847-14851 ◽  
Author(s):  
Christoph Göbl ◽  
Moritz Resch ◽  
Madeleine Strickland ◽  
Christoph Hartlmüller ◽  
Martin Viertler ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Shift Reagent ◽  
Lanthanide Shift Reagent ◽  
Unstructured Proteins
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