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Cations and Anions of Dibenzo[ a , e ]pentalene and Reduction of a Dibenzo[ a , e ]pentalenophane
Author(s) -
Hermann Mathias,
Böttcher Tobias,
Schorpp Marcel,
Richert Sabine,
Wassy Daniel,
Krossing Ingo,
Esser Birgit
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202005131
Subject(s) - dication , chemistry , pentalene , delocalized electron , radical ion , aromaticity , antiaromaticity , photochemistry , unpaired electron , molecule , crystallography , ion , computational chemistry , organic chemistry
Dibenzo[ a , e ]pentalene (DBP) is a non‐alternant conjugated hydrocarbon with antiaromatic character and ambipolar electrochemical behavior. Upon both reduction and oxidation, it becomes aromatic. We herein study the chemical oxidation and reduction of a planar DBP derivative and a bent DBP‐phane. The molecular structures of its planar dication, cation radical and anion radical in the solid state demonstrate the gained aromaticity through bond length equalization, which is supported by nucleus independent chemical shift‐calculations. EPR spectra on the cation radical confirm the spin delocalization over the DBP framework. A similar delocalization was not possible in the reduced bent DBP‐phane, which stabilized itself by proton abstraction from a solvent molecule upon reduction. This is the first report on structures of a DBP cation radical and dication in the solid state and of a reduced bent DBP derivative. Our study provides valuable insight into the charged species of DBP for its application as semiconductor.