Effect of dielectric constant on the rate of electron spin exchange of Fremy's salt in solution

1986 ◽  
Vol 51 (11) ◽  
pp. 2433-2436 ◽  
Author(s):  
Hamza A. Hussain ◽  
Waleed A. A. Kuder
Keyword(s):  
Aqueous Solution ◽  
Dielectric Constant ◽  
Electron Spin ◽  
Spin Exchange ◽  
Bimolecular Collisions

The rate of electron spin exchange in aqueous solution of potassium nitrosodisulphonate K2(SO3)2NO, has been investigated by ESR and found to depend on the dielectric constant of the medium. This observation lead to the calculation of the collision diameter 2 nm which corresponds to bimolecular collisions between species carrying two nagative charges.

Effect of mass on particle diffusion in liquids studied by electron spin exchange and chemical reaction of muonium with oxygen in aqueous solution

1995 ◽  
Vol 91 (13) ◽  
pp. 1935 ◽  
Author(s):  
Emil Roduner ◽  
Philip L. W. Tregenna-Piggott ◽  
Herbert Dilger ◽  
K�bi Ehrensberger ◽  
Masayoshi Senba
Keyword(s):  
Aqueous Solution ◽  
Chemical Reaction ◽  
Electron Spin ◽  
Spin Exchange ◽  
Particle Diffusion ◽  
Diffusion In Liquids

Muonium depolarization by electron spin exchange withO2gas in the temperature range 90–500 K

1989 ◽  
Vol 39 (8) ◽  
pp. 3871-3883 ◽  
Author(s):  
Masayoshi Senba ◽  
Donald G. Fleming ◽  
Donald J. Arseneau ◽  
David M. Garner ◽  
Ivan D. Reid
Keyword(s):  
Electron Spin ◽  
Spin Exchange ◽  
Temperature Range

scholarly journals Antioxidant activity of Induna apple pomace extract

2005 ◽  
pp. 239-246 ◽  
Author(s):  
Sladjana Savatovic ◽  
Sonja Djilas ◽  
Vesna Tumbas ◽  
Jasna Canadanovic-Brunet ◽  
Gordana Cetkovic
Keyword(s):  
Aqueous Solution ◽  
Antioxidant Activity ◽  
Acetic Acid ◽  
Electron Spin Resonance ◽  
Hydroxyl Radicals ◽  
Electron Spin ◽  
Esr Spectroscopy ◽  
Methanol Extract ◽  
Apple Pomace ◽  
Spin Resonance

Different concentrations ofmethanol aqueous solution with or without 0.5% acetic acid and 80% acetone were used to achieve the highest yield of extraction of phenolics from Induna apple pomace. The highest content of phenolics (6.38 mg/g) was detected in the 80% methanol extract. The influence of 80% methanol extract of Induna apple pomace on stable l,l-diphenyl-2-picrylhydrazyl (DPPH) and reactive hydroxyl radicals has been investigated by electron spin resonance (ESR) spectroscopy. Based on the obtained results it can be concluded that the investigated extract is more effective in the DPPH test than on the DMPO-OH scavenging. In both cases antioxidant activity increased with increasing concentration of the investigated extract. The high contents ofphenolics (6.38 mg/g), flavonoids (1.01 mg/g) and flavan-3-ols (0.70 mg/g) in 80% methanol extract indicated that these compounds contributed to the antioxidant activity of Induna apple pomace.

scholarly journals ESR and Optical Studies on the Interaction between Cu(II) and Pepsin

1978 ◽  
Vol 33 (5-6) ◽  
pp. 321-325 ◽  
Author(s):  
L. Sportelli ◽  
H. Neubacher ◽  
W. Lohmann
Keyword(s):  
Aqueous Solution ◽  
Electron Spin Resonance ◽  
Reaction Time ◽  
Conformational Change ◽  
Optical Spectroscopy ◽  
Electron Spin ◽  
Molar Ratio ◽  
Optical Studies ◽  
Spin Resonance

Abstract The interaction of Cu (II) with the protein pepsin has been investigated by means of electron spin resonance (ESR) and optical spectroscopy. Depending on the molar ratio of Cu(II) and pepsin in aqueous solution two different complexes are formed. A third complex can be detected after a reaction time of several days, attributed to a complex with a conformationally changed pepsin. The presence of inhibitors 1,2-epoxy-3-phenoxypropane (EPP) or diazoacetyl-ethylester (DAE) seems to hinder the conformational change. The structure of the three complexes is discussed.

Relaxation und dynamische Kernpolarisation von Protonen in freien Radikalen

1967 ◽  
Vol 22 (6) ◽  
pp. 914-928 ◽  
Author(s):  
D. Stehlik ◽  
K. H. Hausser
Keyword(s):  
Electron Spin ◽  
Molecular Motion ◽  
Spin Exchange ◽  
Intramolecular Interaction ◽  
Coupling Parameter ◽  
Solvent Molecule ◽  
Dipolar Interaction ◽  
Pulse Technique ◽  
Electron Spin Relaxation ◽  
Electronic Spin

In all dynamic nuclear polarisation (DNP) experiments in liquids carried out so far the electronic spin belonged to the paramagnetic molecule while the proton was part of the diamagnetic solvent molecule. In this paper the relaxation and DNP of protons inside free radicals in protonfree solvents is studied.A calculation of the DNP coupling parameter ξ is given for mixed scalar and dipolar intramolecular interaction with simultaneous time dependences by electron spin relaxation, electron spin exchange and molecular motion on the basis of the formalism of ABRAGAM and SOLOMON.Experimental results at 12.5 kGauß were obtained for the t-butyl-protons in the three radicals tri-t-butyl-phenoxyl (TBP), COPPINGER'S Radical (CR) or Galvinoxyl and di-t-butyl-nitroxide (DBNO). The experimental technique differs from the usual NMR-detection in the use of pulse technique and of a dielectric resonator in the microwave equipment.DNP enhancements from high positive to high negative values could be observed corresponding to mixed proton-electron-coupling from dominantly scalar to dominantly dipolar interaction. All results can be at least qualitatively explained by the theory of the intramolecular interaction since the essential parameters and constants of the interaction can be measured with other independent methods.

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