O‐doped nanographenes: the pyrano/pyrylium route towards semiconducting cationic mixed valence complexes

Herein we report an efficient synthesis to prepare O‐doped nanographenes, which derive from the longitudinally and latitudinally p‐extension of pyrene. The derivatives are highly fluorescent and feature low‐oxidation potentials. Exploiting electrooxidation, crystals of cationic mixed valence (MV) complexes were grown in which the organic salts organize into face‐to‐face p‐ p stacks, a favorable solid‐state arrangement for organic electronics. Variable‐temperature EPR measurements and relaxation studies suggest a strong electron delocalization along the longitudinal axis of the columnar p‐stacking architectures. Electric measurements of single crystals of the MV salts exhibited a semiconducting behavior with a remarkable high conductivity at room temperature. These findings further support the idea for which the p‐extension of polycyclic aromatic hydrocarbons featuring precise heteroatom doping topologies, is an attractive approach to enable nanographenes with a broad spectrum of semiconducting properties and high charge mobilities.