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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

77 Scopus citations

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 (US)
Pages (from-to)13236-13239
Number of pages4
JournalJournal of the American Chemical Society
Volume137
Issue number41
DOIs
StatePublished - Oct 21 2015

ASJC Scopus subject areas

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

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