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Reversible excited state electron transfer in an acceptor-acceptor hetero dyad

Jensen, Jesper Dahl ; Louie, Shayan ; He, Yanmei LU ; Chen, Junsheng LU ; Nuckolls, Colin and Laursen, Bo W. (2025) In Chemical Science 16(21). p.9525-9534
Abstract

In this manuscript, we create a new hetero dyad consisting of two electron acceptors with nearly isoenergetic HOMO and LUMO levels, namely perylene diimide (PDI) and aza dioxa triangulenium (ADOTA). This dyad system displays an unusual and reversible excited state electron transfer process. Upon excitation, the dyad shows complete energy transfer from the locally excited PDI to the ADOTA moiety in ∼1 ps, followed by photoinduced electron transfer (PET), forming oxidized PDI and reduced ADOTA. While this PET process is fast (kPET≈ 150 ps), the reversibility establishes an equilibrium between fluorescent locally excited ADOTA and the dark charge shifted PET state. We investigate the formation of and decay from this unusual... (More)

In this manuscript, we create a new hetero dyad consisting of two electron acceptors with nearly isoenergetic HOMO and LUMO levels, namely perylene diimide (PDI) and aza dioxa triangulenium (ADOTA). This dyad system displays an unusual and reversible excited state electron transfer process. Upon excitation, the dyad shows complete energy transfer from the locally excited PDI to the ADOTA moiety in ∼1 ps, followed by photoinduced electron transfer (PET), forming oxidized PDI and reduced ADOTA. While this PET process is fast (kPET≈ 150 ps), the reversibility establishes an equilibrium between fluorescent locally excited ADOTA and the dark charge shifted PET state. We investigate the formation of and decay from this unusual reversible excited state electron transfer system by fs transient absorption and time-resolved fluorescence spectroscopy in different solvent mixtures because the solvent modulates the deactivation rate of the PET state. Electrochemistry confirms that both the local HOMOs and LUMOs of PDI and ADOTA are nearly isoenergetic but can be shifted by solvent polarity, which elucidates the reason for the unusual reversible electron transfer process and its sensitivity to the solvent. We further investigate near degeneracy of the LUMOs through spectroscopy of the chemically reduced dyad. We find that there is an equilibrium between the reduction of the cationic ADOTA to a neutral dyad, which is favored in DCM. However, in DMF, we find reduction of the PDI leads to formation of the zwitterionic dyad.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Chemical Science
volume
16
issue
21
pages
10 pages
publisher
Royal Society of Chemistry
external identifiers
  • pmid:40313520
  • scopus:105004039618
ISSN
2041-6520
DOI
10.1039/d5sc01397f
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2025 The Royal Society of Chemistry.
id
5c301626-100d-4746-8ecb-a94090fed5f5
date added to LUP
2025-08-11 13:43:30
date last changed
2025-09-08 15:46:56
@article{5c301626-100d-4746-8ecb-a94090fed5f5,
  abstract     = {{<p>In this manuscript, we create a new hetero dyad consisting of two electron acceptors with nearly isoenergetic HOMO and LUMO levels, namely perylene diimide (PDI) and aza dioxa triangulenium (ADOTA). This dyad system displays an unusual and reversible excited state electron transfer process. Upon excitation, the dyad shows complete energy transfer from the locally excited PDI to the ADOTA moiety in ∼1 ps, followed by photoinduced electron transfer (PET), forming oxidized PDI and reduced ADOTA. While this PET process is fast (k<sub>PET</sub>≈ 150 ps), the reversibility establishes an equilibrium between fluorescent locally excited ADOTA and the dark charge shifted PET state. We investigate the formation of and decay from this unusual reversible excited state electron transfer system by fs transient absorption and time-resolved fluorescence spectroscopy in different solvent mixtures because the solvent modulates the deactivation rate of the PET state. Electrochemistry confirms that both the local HOMOs and LUMOs of PDI and ADOTA are nearly isoenergetic but can be shifted by solvent polarity, which elucidates the reason for the unusual reversible electron transfer process and its sensitivity to the solvent. We further investigate near degeneracy of the LUMOs through spectroscopy of the chemically reduced dyad. We find that there is an equilibrium between the reduction of the cationic ADOTA to a neutral dyad, which is favored in DCM. However, in DMF, we find reduction of the PDI leads to formation of the zwitterionic dyad.</p>}},
  author       = {{Jensen, Jesper Dahl and Louie, Shayan and He, Yanmei and Chen, Junsheng and Nuckolls, Colin and Laursen, Bo W.}},
  issn         = {{2041-6520}},
  language     = {{eng}},
  month        = {{04}},
  number       = {{21}},
  pages        = {{9525--9534}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Chemical Science}},
  title        = {{Reversible excited state electron transfer in an acceptor-acceptor hetero dyad}},
  url          = {{http://dx.doi.org/10.1039/d5sc01397f}},
  doi          = {{10.1039/d5sc01397f}},
  volume       = {{16}},
  year         = {{2025}},
}