University of Illinois Urbana-Champaign

INVESTIGATION OF ULTRAFAST ELECTRON AND PROTON TRANSFER PROCESSES IN COPPER-ANTHRAQUINONE DONOR-ACCEPTOR MOLECULES

Haddock, Tyler N

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7260.pdf
FE05_1.pptx

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https://hdl.handle.net/2142/122702

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Title
INVESTIGATION OF ULTRAFAST ELECTRON AND PROTON TRANSFER PROCESSES IN COPPER-ANTHRAQUINONE DONOR-ACCEPTOR MOLECULES
Author(s)
Haddock, Tyler N
Contributor(s)
  • Chen, Lin X
  • Mulfort, Karen
  • Henke, Wade C
Issue Date
2023-06-23
Keyword(s)
Photodissociation and photochemistry
Abstract
We have investigated the photochemistry of molecular dyads composed of a light absorbing Cu(I) diimine species co-valently linked to an anthraquinone moiety (CuAnQ). These donor-acceptor molecules serve as Earth-abundant prototypes for studying charge accumulation mechanisms in donor-acceptor-donor triads. We have utilized ultrafast optical and NIR spectroscopy to study the kinetics of the electron transfer, taking advantage of the optical and NIR signatures of the AnQ− radical anion. After excitation into a ¹MLCT band, we observe electron transfer from Cu to AnQ in 10’s of picoseconds, forming a charge-separated state (CSS). The assignment of the CSS to Cu²⁺AnQ− was confirmed by spectroelectrochemical study of the Cu⁺AnQ− species. The CSS relaxes back to the ground state in 3 nanoseconds. In the presence of a protic solvent, the charge-separated state further transforms into a new species. The spectral changes suggest this product results from protonation of the AnQ− into the semiquinone radical (HAnQ•). Accompanying this protonation is an extension of the charge-separated state lifetime from 3 ns to 15 ns. These results provide promise for future studies on the CuAnQCu triad, which can potentially form the double reduced Cu²⁺AnQ²−Cu²⁺ and Cu²⁺HAnQCu²⁺ CSSs. Preliminary experiments which indicate CO₂ binding to the Cu²⁺AnQ− and Cu²⁺HAnQ• CSSs are still underway.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
Text
Genre of Resource
Conference Paper / Presentation
Language
eng
Handle URL
https://hdl.handle.net/2142/122702
DOI
https://doi.org/10.15278/isms.2023.7260

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Abstracts & Presentations - 2023 International Symposium on Molecular Spectroscopy PRIMARY