Elektronentransfer und Kontaktionen-Bildung, 45 [1, 2] Strukturänderungen bei der Einelektronen-Reduktion von Tetraphenylbutatrien zum Radikalanion und bei der Zweifach-Deprotonierung von Tetraphenyl-butin-2 zum Tetraphenylbutatrien-Dianion

Electron Transfer and Contact Ion Pair Formation, 45 [1,2] Structural Changes on Single Electron Reduction of Tetraphenylbutatriene to its Radical Anion and on Twofold Deprotonation of Tetraphenylbutyne-2 to the Tetraphenylbutatriene Dianion

  • Tetraphenylbutatriene is reduced under aprotic conditions to its ESR/ENDOR-spectroscopically characterized radical anion and to its dianion, with both electron transfers quasireversible according to cyclovoltammetric measurements. The alkali cation salts, the red contact ion pair [(H5C6)4C4·⊖][Na⊕ (H3COCH2CH2OCH3)3] and the dark violet contact ion triple [(H5C6)4C4⊖⊖][Li⊕(H3COCH2CH2OCH3)3]2 can be prepared by single electron reduction at a sodium metal mirror or by twofold de-protonation of 1,1,4,4-tetraphenylbutyne-2 using lithium-n-butyl. Their single crystal structures as well as that of the parent acetylene have been determined at low temperatures. The essential structural changes observed are the twisting of both molecular halves (H5C6)2CC relative to each other with increasing negative charge. The simultaneously resulting bond alternancy >C = C = C = C< → >C⊖ - C ≡ C⊖ - C < within the cumulene chain is discussed based on MNDO calculations for the structures determined.

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Author:Hans BockGND, Claudia Arad, Christian NätherORCiDGND, Ilka Göbel, Andreas John, Rüdiger Baur
Parent Title (German):Zeitschrift für Naturforschung, B
Publisher:Verlag der Zeitschrift für Naturforschung
Place of publication:Tübingen
Document Type:Article
Date of Publication (online):2014/06/02
Year of first Publication:1996
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2023/09/23
Tag:Cyclovoltammetry; ESR/ENDOR Spectra; Single Crystal Structures; Tetraphenylbutatriene Radical Anion and Dianion Salts
Page Number:10
First Page:1381
Last Page:1390
Institutes:Biochemie, Chemie und Pharmazie / Biochemie und Chemie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
Licence (German):License LogoCreative Commons - Namensnennung-Nicht kommerziell-Keine Bearbeitung 3.0