Results 361 to 370 of about 251,789 (396)
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g-Tensor anisotropy of DPPH in DPPH2
Journal of Magnetic Resonance (1969), 1976The ESR spectra of polycrystalline samples of the free radical 2-2-diphenyl-1-picrylhydrazyl in dilute concentration in the hydrazine are studied to determine the anisotropy of the g-tensor and the orientation of its symmetry axis. A satisfactory fit to the experimental spectrum is obtained with the hyperfine tensors as given by Holmberg, Livingston ...
Joseph S Chalmers, Peter W France
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Magnetic interactions in solvent-free DPPH
Journal of Magnetism and Magnetic Materials, 1983Abstract Susceptibility and ESR measurements are performed on single crystals of solvent-free 2,2-diphenyl-l-picrylhydrazyl (DPPH) between 1.5 and 300 K. The susceptibility measurements are explained by a pair model but 4% nonpairing paramagnetic centres are observed at low temperatures. These centres probe the dynamics of the spin system and the ESR
Pierre Grobet, J Burg
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E.P.R. in neutron-irradiated DPPH
Physica, 1966Abstract The influence of neutron irradiation of D.P.P.H., as measured by paramagnetic resonance at low temperatures is reported. The observed effects include a considerable increase in the number of spins and in the linewidth and a small but significant change in g -values.
R. Van Audekercke +3 more
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DPPH radical scavenging activity of paracetamol analogues
Tetrahedron, 2012Biochemical studies suggest a direct relationship between the radical scavenging activity of paracetamol (I) and its antipyretic and analgesic action. To evaluate the effect of chemical modifications on the radical scavenging activity of compounds of type I, analogues 1e14 were prepared and submitted to a stable free radical (DPPH; 1,1-diphenyl-2 ...
Alisi, Maria Alessandra +14 more
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ESR Study of the Alkyl Derivatives of DPPH
The Journal of Chemical Physics, 1971The alkyl-substituted compounds of DPPH were investigated by ESR methods. Accurate values of the splitting constants were determined by calculating the experimental spectra. The activation energy of the hindered oscillation of the methylene group, as evaluated from the temperature dependence of the ethyl derivative, was found to be 910 cal/mole ...
M.‐M. Hegyháti, M. Erö‐Gécs
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Critical re-evaluation of DPPH assay: Presence of pigments affects the results.
Journal of Agricultural and Food Chemistry, 2019A limitation of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability (DRSA) due to the presence of pigments and colors in the extracts of plant-based foods was addressed.
JuDong Yeo, F. Shahidi
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DPPH Radical Scavenging Activity of Kaempferol
Advanced Materials Research, 2013The UV-Vis absorption spectrum of kaempferol and DPPH was investigated, the optimum determination wavelength and reaction time for determining the DPPH radical scavenging activity of kaempferol was 517 nm and 30 min, respectively. Kaempferol exhibited strong DPPH radical scavenging activity with a IC50 value of 0.004349 mg·mL-1, which is smaller than ...
Yun Tao Gao +6 more
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ESR.‐Spektrum von Diphenylpicrylhydrazyl (DPPH)
Helvetica Chimica Acta, 1968AbstractThe ESR. sprectra of DPPH in mixed organic solvents have been measured with a K‐band superheterodyne spectrometer and self‐locking magnetometer with high precision. Approximately 150 lines have been resolved in the spectra. Both the zero and first order derivative spectra were analyzed by a line shape analysis program for determination of the ...
Hs.H. Günthard, Z. Haniotis
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E.S.R. of Irradiated DPPH Protected by Polystyrene
Journal of the Physical Society of Japan, 1961The number of electrons in diphenylpicryl hydrazl with polystyrene under gamma -irradiation was studied. It is shown from comparison of experimental and theoretical data that there is not only a shielding effect of polystyrene but also a protection mechanism.
Tokuo Suita, Kohzoh Masuda
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