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Molecular Physics
An International Journal at the Interface Between Chemistry and Physics
Volume 119, 2021 - Issue 1-2: David Parker Festschrift
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Research Articles

Excited-state dynamics of isolated and (micro)solvated methyl sinapate: the bright and shady sides of a natural sunscreen

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Article: e1825850 | Received 21 Jul 2020, Accepted 14 Sep 2020, Published online: 28 Sep 2020
 

ABSTRACT

The increasing awareness of the adverse effects of exposure to UV radiation in combination with the conclusion that presently employed sunscreen agents are far from optimal has led to the need to develop novel UV filters with improved absorption and stability characteristics. Studies of natural sunscreens can provide fundamental insight into strategies to come to a rational design of such filters. Here, we use high-resolution laser spectroscopic methods to study the spectroscopy and excited-state dynamics of methyl sinapate, a prominent plant sunscreen derivative. We find that our experimental approach based on two-color Resonance Enhanced Two-Photon Ionisation spectroscopy enables us to observe a hitherto not observed decay pathway leading to a long-lived state, albeit with a significantly lower yield than in cinnamates and coumarates. In combination with extended excitation spectra and employing the results of quantum chemical calculations a comprehensive picture is obtained of the internal conversion pathways that are accessible to this compound. Similar high-resolution studies on clusters of methyl sinapate with water show how solvent-solute interactions affect the electronic structure and excited-state decay dynamics of the chromophore.

GRAPHICAL ABSTRACT

Acknowledgements

We thank Ivan Romanov and Melania Kozdra for experimental assistance. Jiayun Fan acknowledges a doctoral fellowship from the China Scholarship Council (No. 201808440365). This project has received funding from the European Union's Horizon 2020 research and innovation programme under the grant agreement No. 828753.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by China Scholarship Council [grant number 201808440365]; European Commission [grant number 828753].