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Electronic Relaxation Dynamics in 2-Quinolinones with Extended Conjugation
Alana Fligelman1, Gonto Johns1, Christina Guyn1
1Department of Chemistry and Biochemistry, DePaul University, 1110 West Belden Avenue, Chicago Illinois 60614, United States.
The Journal of Physical Chemistry. A
|November 4, 2021
Summary
This study investigates the photophysics of 2-quinolinones, revealing complex electronic relaxation dynamics. These carbostyrils exhibit competitive decay pathways, offering potential for controlled excited-state manipulation in sensing and catalysis.
Area of Science:
- Photochemistry
- Molecular Spectroscopy
- Organic Chemistry
Background:
- 2-Quinolinones (carbostyrils) are explored for light-driven applications, utilizing their electronic excited states.
- Understanding the photophysical properties and excited-state dynamics of 2-quinolinones is crucial for optimizing their performance.
Purpose of the Study:
- To investigate the photophysics and electronic relaxation dynamics of five 2-quinolinone derivatives with extended conjugation.
- To elucidate the excited-state behavior, including fluorescence lifetimes and intersystem crossing, using advanced spectroscopic techniques.
Main Methods:
- Static and dynamic spectroscopy (time-correlated single photon counting, transient absorption spectroscopy).
- Supporting density functional theory (DFT) calculations.
- Optical excitation with near-UV light (350 nm).
Main Results:
- Extended conjugation caused red-shifted absorbance and emission.
- Fluorescence lifetimes ranged from 849.3 ps to 4.586 ns.
- Evidence of S1 excited-state relaxation and triplet excited-state formation was observed, indicating competitive relaxation pathways.
Conclusions:
- The 2-quinolinone derivatives exhibit a complex, multi-pathway electronic relaxation scheme.
- The observed dynamics suggest potential for chemical control over excited-state relaxation in these molecules.
- This work provides fundamental insights into the photophysical behavior of carbostyrils for future applications.
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