The use of nuclear magnetic double resonance to detect and characterise phenolic OH groups

1966 ◽  
pp. 295 ◽  
Author(s):  
J. Feeney ◽  
A. Heinrich
Keyword(s):  
Double Resonance ◽  
Oh Groups ◽  
Phenolic Oh Groups ◽  
Nuclear Magnetic

Statistical Analysis of the Relationship Between Antioxidant Activity and the Structure of Flavonoid Compounds

2019 ◽  
Vol 70 (9) ◽  
pp. 3103-3107 ◽  
Author(s):  
Ioana Glevitzky ◽  
Gabriela Alina Dumitrel ◽  
Mirel Glevitzky ◽  
Bianca Pasca ◽  
Pavel Otrisal ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Activities ◽  
Basic Structure ◽  
Oh Groups ◽  
Flavonoid Compounds ◽  
Chi Squared ◽  
Potential Link ◽  
Van Der Waals Surface ◽  
The Relationship ◽  
Phenolic Oh Groups

Using different methods of statistics, this paper aims to highlight the potential link between the antioxidant activity of flavonoids and the corresponding molecular descriptors. By calculating the descriptors (van der Waals surface (A), molar volume (V), partition coefficient (LogP), refractivity (R), polarizability (a), forming heat (Hformation), hydration energy (Ehidr), the dipole moment (mt)), together with antioxidant activities (RSA) calculated or taken from the literature, number of phenolic -OH groups and the presence (2) or absence (1) of C2=C3 double bond) for 29 flavonoid compounds and by intercorrelation between the studied parameters, the link between the number of phenolic groups grafted to the basic structure of flavonoids and their antioxidant activity was confirmed. Simultaneously, by using the chi-squared test and the intercorrelations matrix, a satisfactorily correlation coefficient (r2=0.5678; r=0.7536) between the structure of the flavonoids and their activity was obtained, fact that confirms the correlation of the antioxidant activity with the number of -OH phenolic groups.

scholarly journals Nuclear Magnetic Double-Resonance Spectrum of a Strongly Coupled Two-Spin System

1965 ◽  
Vol 137 (5A) ◽  
pp. A1477-A1482 ◽  
Author(s):  
B. D. Nageswara Rao ◽  
J. D. Baldeschwieler ◽  
J. M. Anderson
Keyword(s):  
Spin System ◽  
Resonance Spectrum ◽  
Double Resonance ◽  
Strongly Coupled ◽  
Nuclear Magnetic

Properties of humic and fulvic acids under the long-term use of fertilizers in a rice-wheat-cowpea system on a mollisol

2007 ◽  
Vol 55 (3) ◽  
pp. 293-298
Author(s):  
D. Das ◽  
Nand Ram
Keyword(s):  
Nutrient Management ◽  
Fulvic Acids ◽  
Oh Groups ◽  
Molecular Weights ◽  
Northern India ◽  
Carboxylic Groups ◽  
Long Term Experiment ◽  
C And N ◽  
Phenolic Oh Groups

The properties of humic (HA) and fulvic acids (FA) isolated from a 27-year-old long-term experiment with rice-wheat-cowpea on a Mollisol in northern India were evaluated for elemental composition and functional groups. As compared to fallow, C, H and N decreased, while O increased in the control, but the use of NPK+FYM over the years enhanced the C and N of humic substances. The carboxylic (-COOH) and phenolic-OH groups declined in the control, but improved with NPK+FYM in comparison to fallow. Carboxylic groups (-COOH) contributed about 2–3 times more in HA and 4–5 times more in FA than the respective phenolic-OH groups to the molecular weights of these fractions of soil organic matter. The results suggested the role of integrated nutrient management in maintaining active soil humus over the years.

ChemInform Abstract: NMR AND NUCLEAR MAGNETIC DOUBLE RESONANCE METHODS FOR STUDYING 1-MERCAPTO-2-THIABICYCLO(4.4.0)DECENES

1977 ◽  
Vol 8 (17) ◽  
pp. no-no
Author(s):  
I. YA. EVTUSHENKO ◽  
S. K. KLIMENKO ◽  
V. G. KHARCHENKO ◽  
B. I. IONIN
Keyword(s):  
Double Resonance ◽  
Nuclear Magnetic
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