Ultrafast Photoinduced Symmetry-Breaking Charge Separation and Electron Sharing in Perylenediimide Molecular Triangles

Yilei Wu, Ryan M. Young, Marco Frasconi, Severin T. Schneebeli, Peter Spenst, Daniel M. Gardner, Kristen E. Brown, Frank Würthner, J. Fraser Stoddart, Michael R. Wasielewski

Research output: Contribution to journalArticle

59 Citations (Scopus)

Abstract

We report on a visible-light-absorbing chiral molecular triangle composed of three covalently linked 1,6,7,12-tetra(phenoxy)perylene-3,4:9,10-bis(dicarboximide) (PDI) units. The rigid triangular architecture reduces the electronic coupling between the PDIs, so ultrafast symmetry-breaking charge separation is kinetically favored over intramolecular excimer formation, as revealed by femtosecond transient absorption spectroscopy. Photoexcitation of the PDI triangle dissolved in CH2Cl2 gives PDI+•-PDI-• in ΔCS = 12.0 ± 0.2 ps. Fast subsequent intramolecular electron/hole hopping can equilibrate the six possible energetically degenerate ion-pair states, as suggested by electron paramagnetic resonance/electron-nuclear double resonance spectroscopy, which shows that one-electron reduction of the PDI triangle results in complete electron sharing among the three PDIs. Charge recombination of PDI+•-PDI-• to the ground state occurs in ΔCR = 1.12 ± 0.01 ns with no evidence of triplet excited state formation.

Original languageEnglish
Pages (from-to)13236-13239
Number of pages4
JournalJournal of the American Chemical Society
Volume137
Issue number41
DOIs
Publication statusPublished - Oct 21 2015

ASJC Scopus subject areas

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

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    Wu, Y., Young, R. M., Frasconi, M., Schneebeli, S. T., Spenst, P., Gardner, D. M., Brown, K. E., Würthner, F., Stoddart, J. F., & Wasielewski, M. R. (2015). Ultrafast Photoinduced Symmetry-Breaking Charge Separation and Electron Sharing in Perylenediimide Molecular Triangles. Journal of the American Chemical Society, 137(41), 13236-13239. https://doi.org/10.1021/jacs.5b08386