title: Electron acceptors based on functionalizable cyclopenta[hi]aceanthrylenes and dicyclopenta[de,mn]tetracenes.
abstract: We report the synthesis and selective functionalization of two externally fused cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs) and demonstrate their electron accepting behavior. 2,7-Bis(trimethylsilyl)cyclopenta[hi]aceanthrylene (1) and 2,8-bis(trimethylsilyl)dicyclopenta[de,mn]tetracene (4) were prepared in a one-pot, palladium-catalyzed cross-coupling of (trimethylsilyl)acetylene and either 9,10-dibromoanthracene or 5,11-dibromotetracene, respectively. The trimethylsilyl groups were selectively converted into bromides via substitution with N-bromosuccinimide to create universal partners (2 and 6) for metal-catalyzed cross-coupling reactions. To demonstrate the utility of the halogenated CP-PAHs, we successfully employed a Sonogashira cross-coupling between the CP-PAHs and a phenylacetylene derivative. The resulting compounds (3 and 7) were found to be highly conjugated between the CP-PAH core and the substituents, as demonstrated by large bathochromic shifts in the absorption spectra as well as density functional theory calculations. Ethynylated CP-PAHs 3 and 7 were found to possess low optical bandgaps (1.52 and 1.51 eV, respectively) and displayed two reversible reductions. We further demonstrated the fullerene-like electron-accepting behavior of 3 through solution-phase fluorescence quenching of the prototypical electron donor, poly(3-hexylthiophene).
authors.affiliation: Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, United States.
authors.forename: Jordan D
authors.initials: JD
authors.lastname: Wood
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Jellison
authors.forename: Aaron D
authors.initials: AD
authors.lastname: Finke
authors.forename: Lichang
authors.initials: L
authors.lastname: Wang
authors.forename: Kyle N
authors.initials: KN
authors.lastname: Plunkett