Varying the Interpentacene Electronic Coupling to Tune Singlet Fission

Ilias Papadopoulos, Johannes Zirzlmeier, Constantin Hetzer, Youn J. Bae, Matthew D. Krzyaniak, Michael R Wasielewski, Timothy Clark, Rik R. Tykwinski, Dirk M. Guldi

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12 Citations (Scopus)

Abstract

We have designed and used four different spacers, denoted A-D, to connect two pentacenes and to probe the impact of intramolecular forces on the modulation of pentacene-pentacene interactions and, in turn, on the key steps in singlet fission (SF), that is, the 1 (S 1 S 0 )-to- 1 (T 1 T 1 ) as well as 1 (T 1 T 1 )-to- 5 (T 1 T 1 ) transitions by means of transient absorption and electron paramagnetic resonance measurements. In terms of the 1 (S 1 S 0 )-to- 1 (T 1 T 1 ) transition, a superexchange mechanism, that is, coupling to a higher-lying CT state to generate a virtual intermediate, enables rapid SF in A-D. Sizeable electronic coupling in A and B opens, on one hand, an additional pathway, that is, the population of a real intermediate, and changes, on the other hand, the mechanism to that of hopping. In turn, A and B feature much higher 1 (T 1 T 1 ) quantum yields than C and D, with a maximum value of 162% for A. In terms of the 1 (T 1 T 1 )-to- 5 (T 1 T 1 ) transition, the sizable electronic coupling in A and B is counterproductive, and C and D give rise to higher 5 (T 1 T 1 )-to-(T 1 + T 1 ) quantum yields than A and B, with a maximum value of 85% for D.

Original languageEnglish
Pages (from-to)6191-6203
Number of pages13
JournalJournal of the American Chemical Society
Volume141
Issue number15
DOIs
Publication statusPublished - Apr 17 2019

ASJC Scopus subject areas

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

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    Papadopoulos, I., Zirzlmeier, J., Hetzer, C., Bae, Y. J., Krzyaniak, M. D., Wasielewski, M. R., Clark, T., Tykwinski, R. R., & Guldi, D. M. (2019). Varying the Interpentacene Electronic Coupling to Tune Singlet Fission. Journal of the American Chemical Society, 141(15), 6191-6203. https://doi.org/10.1021/jacs.8b09510