Charge transfer complexes of linear acenes with a new acceptor perfluoroanthraquinone. The interplay of charge transfer and F•••F interactions

Two charge-transfer bicomponent 1:1 crystals of polycyclic aromatic hydrocarbons (anthracene and tetracene) with a new acceptor molecule (perfluoroanthraquinone) were grown by slow evaporation from solutions in toluene. In both crystals, pi-pi stacks of alternating donor and acceptor molecules are observed. In the tetracene-perfluoroanthraquinone complex, face-to-face stacking is the prevailing intermolecular interaction, while in the complex of anthracene-perfluoroanthraquinone multiple interactions (stacking, F center dot center dot center dot H, O center dot center dot center dot H, F center dot center dot center dot F) of similar energy are observed, as revealed by the Quantum Theory of Atoms in Molecules method, resulting in the formation of polymorphic modifications, as determined by X-ray single crystal diffraction and differential scanning calorimetry. The charge-transfer degree was estimated to be equal to 0.04 and 0.08 e in anthracene- and tetracene-containing complexes, respectively.