Pyrene Molecular Orbital Shuffle—Controlling Excited State and Redox Properties by Changing the Nature of the Frontier Orbitals

Julia Merz, Julian Fink, Alexandra Friedrich, Ivo Krummenacher, Hamad H. Al Mamari, Sabine Lorenzen, Martin Haehnel, Antonius Eichhorn, Michael Moos, Marco Holzapfel, Holger Braunschweig, Christoph Lambert, Andreas Steffen, Lei Ji, Todd B. Marder

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33 Citations (Scopus)

Abstract

We show that by judicious choice of substituents at the 2- and 7-positions of pyrene, the frontier orbital order of pyrene can be modified, giving enhanced control over the nature and properties of the photoexcited states and the redox potentials. Specifically, we introduced a julolidine-like moiety and Bmes2 (mes=2,4,6-Me3C6H2) as very strong donor (D) and acceptor (A), respectively, giving 2,7-D-π-D- and unsymmetric 2,7-D-π-A-pyrene derivatives, in which the donor destabilizes the HOMO−1 and the acceptor stabilizes the LUMO+1 of the pyrene core. Consequently, for 2,7-substituted pyrene derivatives, unusual properties are obtained. For example, very large bathochromic shifts were observed for all of our compounds, and unprecedented green light emission occurs for the D/D system. In addition, very high radiative rate constants in solution and in the solid state were recorded for the D-π-D- and D-π-A-substituted compounds. All compounds show reversible one-electron oxidations, and Jul2Pyr exhibits a second oxidation, with the largest potential splitting (ΔE=440 mV) thus far reported for 2,7-substituted pyrenes. Spectroelectrochemical measurements confirm an unexpectedly strong coupling between the 2,7-substituents in our pyrene derivatives.

Original languageEnglish
Pages (from-to)13164-13180
Number of pages17
JournalChemistry - A European Journal
Volume23
Issue number53
DOIs
Publication statusPublished - Sep 21 2017

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Keywords

  • borylation
  • charge transport
  • luminescence
  • pyrene
  • spectroelectrochemistry

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Merz, J., Fink, J., Friedrich, A., Krummenacher, I., Al Mamari, H. H., Lorenzen, S., Haehnel, M., Eichhorn, A., Moos, M., Holzapfel, M., Braunschweig, H., Lambert, C., Steffen, A., Ji, L., & Marder, T. B. (2017). Pyrene Molecular Orbital Shuffle—Controlling Excited State and Redox Properties by Changing the Nature of the Frontier Orbitals. Chemistry - A European Journal, 23(53), 13164-13180. https://doi.org/10.1002/chem.201702594