Structural Dependence of Redox-Induced Dimerization as Studied by In Situ ESR/UV/Vis-NIR Spectroelectrochemistry: The Fluoranthenopyracylene Oligomers This work was supported by the Deutsche Forschungsgemainschaft. PR thanks Humboldt Foundation and Slovak Grant Agency for financial support. The authors thank Dr. M. Breza (STU Bratislava) for quantum-chemical calculations.

Chain length and dimerization, the missing link? The influence of chain length on the dimerization of the extended π-conjugated ladder-type fluoranthenopyracylene oligomers (see picture) during charge transfer is studied by cyclic voltammetry and in situ ESR/UV/Vis-NIR spectroelectrochemistry. The π conjugation in higher extended structures is found to be sufficient for the stabilization of charges in the molecule and disfavors chemical dimerization. This finding is an indication that dimerization in organic conducting polymers may not be a necessary stabilization mechanism of general validity.