Elektronentransfer und Ionenpaar-Bildung, 48 [1]. Titrationen von Tetraphenyl-p-benzochinon mit Natrium- und Kaliummetall in aprotischen Lösungen
Electron transfer and ion pair formation, 48 [1]. Titrations of tetraphenyl-p-benzoquinone with sodium and potassium metals in aprotic solutions
- UV/VIS and ESR spectra of electron transfer reaction products in aprotic (cH⊕ < 0,1 ppm) solution can be measured in an especially designed and sealed glass apparatus and provide information on unknown facets of the microscopic pathway through the network of interdependent equilibria. For tetraphenyl-p-benzoquinone in tetrahydrofuran, single-electron reduction by a sodium metal mirror produces a red solution and, unexpectedly, after addition of 2.2.2. cryptand, contact with a potassium metal mirror generates a green (!) one. For both, ESR/ENDOR spectra prove the presence of tetraphenyl-p-benzoquinone radical anion. UV/VIS measurements provide the clue: In the equilibrium revealed by repetetive spectra recording, M·⊖solv + Me⊕solv ⇄ [M·⊖···Me⊖]solv, the radical anion is green (vm = 16900 cm-1) and the contact ion pair red (vm=18900 cm-1 ). On ion pair formation, therefore, the excitation energy of the radical anion increases by 0.25 eV.
Author: | Hans BockGND, Markus KleineGND |
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URN: | urn:nbn:de:hebis:30:3-816507 |
DOI: | https://doi.org/10.1515/znb-1996-0902 |
ISSN: | 1865-7117 |
ISSN: | 0932-0776 |
Parent Title (German): | Zeitschrift für Naturforschung, B |
Publisher: | Verlag der Zeitschrift für Naturforschung |
Place of publication: | Tübingen |
Document Type: | Article |
Language: | German |
Date of Publication (online): | 2014/06/02 |
Year of first Publication: | 1996 |
Publishing Institution: | Universitätsbibliothek Johann Christian Senckenberg |
Release Date: | 2024/01/18 |
Tag: | Alkaline and Alkaline Earth Metals; Aprotic Solution; Tetraphenyl-p-benzoquinone Reduction; UV/VIS Spectra |
Volume: | 51.1996 |
Issue: | 9 |
Page Number: | 7 |
First Page: | 1222 |
Last Page: | 1228 |
Institutes: | Biochemie, Chemie und Pharmazie / Biochemie und Chemie |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften |
Sammlungen: | Universitätspublikationen |
Licence (German): | Creative Commons - Namensnennung-Nicht kommerziell-Keine Bearbeitung 3.0 |