Relaxation Dynamics in Dihydroxychalcones: Insights from Ultrafast Spectroscopy and Quantum Computations.
Simin Roshan1, Michael Hymas2, Matthieu M Mention3
1Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran.
ACS Physical Chemistry Au
|December 4, 2025
Summary
Chalcones offer natural photoprotection for sunscreens. Chemical modification of chalcones, like adding an alpha-methoxy group, significantly speeds up their ability to harmlessly dissipate UV energy, enhancing their sunscreen potential.
Area of Science:
- Photochemistry
- Natural Products
- Computational Chemistry
Background:
- Chalcones are natural compounds with potential UV-protective properties.
- Sunscreen formulations benefit from effective photoprotective agents.
- Understanding chalcone photophysics is key to optimizing their use.
Purpose of the Study:
- To investigate the photophysical differences between two chalcone derivatives.
- To explore how chemical modifications affect chalcone photoprotection mechanisms.
- To assess the potential of functionalized chalcones in sunscreen applications.
Main Methods:
- Femtosecond transient electronic absorption spectroscopy for experimental photophysics.
- High-level quantum computations for theoretical analysis.
- Nonadiabatic dynamics simulations to model excited-state behavior.
Main Results:
- Functionalization at the alpha carbon accelerates nonradiative deactivation in chalcones.
- An alpha-methoxy group on 4,4'-dihydroxychalcone significantly shortens excited-state lifetime.
- Theoretical calculations reveal a barrierless S1/S0 conical intersection in the modified chalcone, facilitating rapid energy dissipation.
Conclusions:
- Chemical modifications, specifically at the aliphatic bridge, can drastically alter chalcone photophysical behavior.
- Targeted structural changes enhance the efficiency of UV energy dissipation in chalcones.
- These findings support the development of advanced sunscreen ingredients based on chalcone derivatives.
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