Oxygen‐Bridged Quasi‐Planar para‐Phenylenediamine and Its Oxidized States

A quasi‐planar N , N , N’ , N’ ‐tetraphenyl‐ para ‐phenylenediamine, where all the phenyl rings are tethered by four oxygen atoms to embed quasi‐planar triphenylamine moieties into the molecular skeleton, was prepared and characterized to evaluate the impact by incorporating the structural rigidity. The monocationic and dicationic species could be selectively generated, depending on the type of oxidizing agents used. Spectroscopic and X‐ray diffraction analyses revealed the radical cation was in a unique charge/spin delocalized class III mixed‐valence state due to an exquisite balance between the electronic effect by the oxygen‐bridges and the rigidity of molecular framework.