title: Benzo[e]pyrene skeleton dipyrylium dication with a strong donor-acceptor-donor interaction, and its two-electron reduced molecule.
abstract: 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 (4n+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.
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: Koya Prabhakara
authors.initials: KP
authors.lastname: Rao
authors.forename: Mio
authors.initials: M
authors.lastname: Kondo
authors.forename: Ryota
authors.initials: R
authors.lastname: Sakamoto
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Kusamoto
authors.forename: Michihiro
authors.initials: M
authors.lastname: Nishikawa
authors.forename: Shoko
authors.initials: S
authors.lastname: Kume
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nihei
authors.forename: Hiroki
authors.initials: H
authors.lastname: Oshio
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nishihara