| | 1 | Author
| Berthold Kiefer, Helmut Sapper, WolfgangL. Ohm Ann | Requires cookie* | | | Title
| The Influence of Amino Acid Ligands and Vitamin C on the Reduction Potential of Fe(III): Polarographie and Electron Spin Resonance Investigations  | | | | Abstract
| The pH dependence o f Fe(III)-am ino acid com plexes has been studied polarographically and by means o f ESR spectroscopy. It could be shown that, at least, two com plexes exist: one with a low m olecular weight, ESR detectable at acid pH. and one with a high molecular w eight at alkaline pH, ESR non detectable. The half wave potential o f Fe (III) is lowered by am ino acid ligands. The redox interaction o f the Fe(III)-amino acid com plexes with vitam in C results in a decrease o f the ascorbyl radical concentration. Ascorbic acid also forms a com plex with Fe(III) as in dicated by a polarographic half wave potential near -0.55 V vs. S.C.E. at pH 7. | | | |
Reference
| Z. Naturforsch. 39c, 102—106 (1984); received September 22 1983 | | | |
Published
| 1984 | | | |
Keywords
| Ferrous Ions Ascorbic Acid, Redox-Potential, Polarography, ESR -Spectroscopy | | | |
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| default:Reihe_C/39/ZNC-1984-39c-0102.pdf | | | | Identifier
| ZNC-1984-39c-0102 | | | | Volume
| 39 | |
| 2 | Author
| MartinG. Peter, HartmutB. Stegmann, Hoang Dao-Ba, Klaus Scheffler | Requires cookie* | | | Title
| | | | | Abstract
| ESR-spectra were recorded during the oxidation of N-acetyldopamine and N-ß-alanyldopamine in aqueous solutions. Semiquinone radicals were detected under conditions of spin stabilization by Z n2+ 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 eventual ly from intermolecular Michael-type addition of nitrogen nucleophiles. | | | |
Reference
| Z. Naturforsch. 40c, 535—538 (1985); received January 31 1985 | | | |
Published
| 1985 | | | |
Keywords
| ESR-Spectroscopy, Catecholamines, Semiquinones, Insect Cuticle | | | |
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| default:Reihe_C/40/ZNC-1985-40c-0535.pdf | | | | Identifier
| ZNC-1985-40c-0535 | | | | Volume
| 40 | |
| 3 | Author
| Christoph Eischenbroich, Edgar Bilger, Reinhart Möckel | Requires cookie* | | | Title
| Metall-7r-Komplexe von Benzolderivaten, XX [1] Über die Cokondensation des Phenanthrens mit Chromatomen - Reaktivität, Redoxverhalten, ESR-und NMR-spektroskopische Untersuchungen Metal-^-Complexes of Benzene Derivatives, XX [1] Cocondensation of Phenanthrene with Chromium Atoms - Reactivity, Redox Behavior, ESR and NMR Spectroscopic Investigation | | | | Abstract
| Cocondensation of chromium atoms with phenanthrene vapor affords bis(^ 1 ' 2 ' 3 ' 4 ' 10a -4a -phenanthrene)chromium (4). X H NMR spectroscopy reveals, that the diastereomers 4 (rac) and 4' (meso) are formed in a 2:1 ratio. Cyclic voltammetric studies on 4 show, that four oxidation states are accessible: 4t, 4, 4t, 4 2+ [E° = —2.235 (rev.), —0.651 (rev.), + 0.82 (irrev.) V vs. SCE]. The radical ions 4t and 4 7 are characterized by ESR spectro-scopy in fluid and rigid solutions. Prominent feature of these species is the inverse relative magnitude of the g-tensor components: gn(41") > gi(4t); gn(47) < gi(47). | | | |
Reference
| Z. Naturforsch. 38b, 1357—1364 (1983); eingegangen am 30. Juni 1983 | | | |
Published
| 1983 | | | |
Keywords
| Cocondensation, Condensed Arenes, Bis(arene)transitionmetal Complexes, ESR Spectroscopy, Cyclic Voltammetry | | | |
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| default:Reihe_B/38/ZNB-1983-38b-1357.pdf | | | | Identifier
| ZNB-1983-38b-1357 | | | | Volume
| 38 | |
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