Benzo[ e ]pyrene Skeleton Dipyrylium Dication with a Strong Donor–Acceptor–Donor Interaction, and Its Two‐Electron Reduced Molecule

The donor–acceptor–donor (D–A–D) conjugated molecules 1,4‐bis(diarylaminophenylethynyl)anthraquinone (1,4‐Am 2 Aq) and 1,4‐bis(ferrocenylethynyl)anthraquinone (1,4‐Fc 2 Aq), undergo a double proton cyclization reaction with bis(trifluoromethanesulfone)imide acid (TFSIH) to yield 1,4‐bis(diarylaminophenyl or ferrocenyl) dipyrylium salts [1,4‐R 2 Pyl 2 ](TFSI) 2 (R=Am or Fc) with novel planar pentacyclic structures similar to the aromatic benzo[ e ]pyrene‐type skeleton. [1,4‐Am 2 Pyl 2 ](TFSI) 2 could be reduced to give the neutral molecule [1,4‐Am 2 Pyl 2 ] 0 , which is stable and maintains the benzo[ e ]pyrene‐type skeleton. To the best of our knowledge, this is the first oxygen‐atom‐containing polycyclic aromatic hydrocarbon with 22 (4 n +2) π‐electrons. The obtained condensed‐ring benzo[ e ]pyrene‐type skeleton compounds show physical and chemical properties that are significantly different from those of [1,5‐Am 2 Pyl 2 ](TFSI) 2 , which has a perylene‐type skeleton.