Photoinitiated charge transport through π-stacked electron conduits in supramolecular ordered assemblies of donor-acceptor triads

Joseph E. Bullock, Raanan Carmieli, Sarah M. Mickley, Josh Vura-Weis, Michael R. Wasielewski

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Photochemical electron donor-acceptor triads having an aminopyrene primary donor (APy) and a p-diaminobenzene secondary donor (DAB) attached to either one or both imide nitrogen atoms of a perylene-3,4:9,10-bis(dicarboximide) (PDI) electron acceptor were prepared to give DAB-APy-PDI and DABAPy-PDI-APy-DAB. In toluene, both triads are monomeric, but in methylcyclohexane, they self-assemble into ordered helical heptamers and hexamers, respectively, in which the PDI molecules are π-stacked in a columnar fashion, as evidenced by small- and wide-angle X-ray scattering. Photoexcitation of these supramolecular assemblies results in rapid formation of DAB-PDI spin-polarized radical ion pairs having spin-spin dipolar interactions, which show that the average distance between the two radical ions is much larger in the assemblies (31 Å) than it is in their monomeric building blocks (23 Å). This work demonstrates that electron hopping through the π-stacked PDI molecules is fast enough to compete effectively with charge recombination (40 ns) in these systems, making these materials of interest as photoactive assemblies for artificial photosynthesis and organic photovoltaics.

Original languageEnglish
Pages (from-to)11919-11929
Number of pages11
JournalJournal of the American Chemical Society
Issue number33
Publication statusPublished - Aug 26 2009


ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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