ESR spectra and structure of the aquo complex [Fe(H2O)6]3+ in frozen aqueous solutions of ferric nitrate

1981 ◽  
Vol 17 (2) ◽  
pp. 210-213 ◽  
Author(s):  
A. F. Karimova
Keyword(s):  
Aqueous Solutions ◽  
Esr Spectra ◽  
Ferric Nitrate ◽  
Aquo Complex

Detection of Semiquinone Radicals of N-Acylcatecholamines in Aqueous Solution

1985 ◽  
Vol 40 (7-8) ◽  
pp. 535-538 ◽  
Author(s):  
Martin G. Peter ◽  
Hartmut B. Stegmann ◽  
Hoang Dao-Ba ◽  
Klaus Scheffler
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Esr Spectra ◽  
Semiquinone Radicals ◽  
Spin Stabilization ◽  
Michael Type Addition ◽  
Nitrogen Nucleophiles

Abstract ESR-spectra were recorded during the oxidation of N-acetyldopamine and N-β-alanyldopamine in aqueous solutions. Semiquinone radicals were detected under conditions of spin stabilization by Zn2+ ions. The appearance of the spectra was the same in the presence or in the absence of proteins. No evidence was obtained for the formation of products that could have arisen eventually from intermolecular Michael-type addition of nitrogen nucleophiles.

Chemistry of salts in aqueous solutions: Applications, experiments, and theory

2011 ◽  
Vol 83 (5) ◽  
pp. 1015-1030 ◽  
Author(s):  
Wolfgang Voigt
Keyword(s):  
Aqueous Solutions ◽  
Phase Behavior ◽  
Chemical Reactivity ◽  
Salt Water ◽  
Physical Models ◽  
Experimental Investigations ◽  
Ferric Nitrate ◽  
Model Parameters ◽  
Natural Occurrence ◽  
Structure Property

Salts comprise a very large and important group of chemical compounds. Natural occurrence of salts and industrial processes of their recovery, conversion, purification, and use depend on solubility phenomena and their chemistry in aqueous solutions, mostly in multi-ion systems. Modeling of these processes as well as developing new ones requires knowledge of the properties of the aqueous salt solutions in extended T-p-x ranges including a growing number of components in solutions (CO2, SO2, lithium salts, salts of rare earth metals, actinides, etc.). At least for the thermodynamic properties, the general accepted methodology is to use thermodynamic databases of aqueous species and solids in combination with an appropriate ion-interaction model to perform equilibrium calculations for species distributions in solution and phase equilibria. The situation in respect to available thermodynamic models and data for their parameterization is discussed at selected examples. Thereby, the importance of accurate experimental determinations of phase equilibrium data for derivation of model parameters is emphasized. Furthermore, it is concluded that experimental investigations should follow a chemical systematic. Simple physical models or quantum chemical calculations cannot predict unknown quantities in the databases with sufficient accuracy. Finally, solubility changes in salt-water systems at enhanced temperatures are considered. Systems, which can be considered as molten hydrates, display interesting phase behavior and chemical reactivity as protic ionic liquids. The latter can be exploited in chemical syntheses to substitute mixtures of concentrated acids like HNO3/H2SO4 by simple salts like ferric nitrate. For an understanding of the chemical and phase behavior of water-salt systems in terms of structure–property relations, a renaissance of chemical guided basic investigations of such systems would be worthwhile.

Spin trapping of radicals formed during radiolysis of aqueous solutions. Direct electron spin resonance observations

1976 ◽  
Vol 54 (2) ◽  
pp. 275-279 ◽  
Author(s):  
Frederick Peter Sargent ◽  
Edward Michael Gardy
Keyword(s):  
Electron Spin Resonance ◽  
Aqueous Solutions ◽  
Electron Spin ◽  
Direct Observation ◽  
Electron Accelerator ◽  
Esr Spectra ◽  
Spin Trapping ◽  
Spin Resonance

It is shown that esolv, H•, and OH formed by the radiolysis of water by 3 MeV electrons are trapped by nitroso and nitrone compounds to give nitroxides with well defined esr spectra. Three spin trapping agents were used, nitroso-t-butane, phenyl-t-butyl nitrone, and 5,5′-dimethyl pyrroline-1-oxide. The latter was shown to be an excellent compound for these studies. Complications due to the instability of some of the nitroxides were overcome by coupling the electron accelerator to the esr spectrometer to permit direct observation of the spectra.

Spin trapping of the azide radical with nitroso compounds

1982 ◽  
Vol 60 (12) ◽  
pp. 1597-1597 ◽  
Author(s):  
Walter Kremers ◽  
Grant W Koroll ◽  
Ajit Singh
Keyword(s):  
Electron Spin Resonance ◽  
Aqueous Solutions ◽  
Hydroxyl Radicals ◽  
Electron Spin ◽  
Esr Spectra ◽  
Spin Trapping ◽  
Nitroso Compounds ◽  
Spin Traps ◽  
Spin Resonance

Azide radicals (N3·) are formed in aqueous solutions by the reaction of hydroxyl radicals (·OH) with azide anions (N3aq−). Azide radicals have been spin trapped with three nitroso spin traps: nitrosodurene (ND), 2,6-dideutero-3,5-dibromo-4-nitrosobenzene sulfonate (DDNBS), and 2-methyl-2-nitrosopropane (MNP). The electron spin resonance (esr) spectra show the presence of two molecules of the spin traps in the spin-trapped species.

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