Einelektronen-Redox-Reaktionen von Octaphenyl[4]radialen: Erzeugung und ESR/ENDOR-Charakterisierung seines Radikal-Anions und Radikal-Kations

One-Electron Redox Reactions of Octaphenyl[4]radialene: Generation and ESR/ENDOR Characterisation of Its Radical Anion and Radical Cation The cyclovoltammograms of octaphenyl[4]radialene in DMF or THF at room temperature disclose each two quasireversible reduction and oxidation potentials at ?1.4 V/?1.7 V and +0.7 V/+0.9 V. Accordingly, both the radical anion and the radical cation can be generated: Ph₈C by K metal mirror reduction of a [2.2.2]cryptand containing THF solution, and Ph₈C by TI^3⊕(^?OOCCF₃)₃ oxidation in H₂CCl₂. Their ESR/ENDOR and General Triple spectra differ considerably in the number of resolved ¹H couplings (M^·?: 5 and M^·⊕: 3) as well as in their spectral widths (M^·?: a_1H 0.090 to 0.017 mT; M^·⊕: a_1H 0.066 to 0.023 mT) suggesting different changes in the D_2d structure of the neutral molecule on electron uptake or extrusion.