Issue 40, 2016

Bottom-up excited state dynamics of two cinnamate-based sunscreen filter molecules

Abstract

Methyl-E-4-methoxycinnamate (E-MMC) is a model chromophore of the commonly used commercial sunscreen agent, 2-ethylhexyl-E-4-methoxycinnamate (E-EHMC). In an effort to garner a molecular-level understanding of the photoprotection mechanisms in operation with E-EHMC, we have used time-resolved pump–probe spectroscopy to explore E-MMC's and E-EHMC's excited state dynamics upon UV-B photoexcitation to the S1 (11ππ*) state in both the gas- and solution-phase. In the gas-phase, our studies suggest that the excited state dynamics are driven by non-radiative decay from the 11ππ* to the S3 (11nπ*) state, followed by de-excitation from the 11nπ* to the ground electronic state (S0). Using both a non-polar-aprotic solvent, cyclohexane, and a polar-protic solvent, methanol, we investigated E-MMC and E-EHMC's photochemistry in a more realistic, ‘closer-to-shelf’ environment. A stark change to the excited state dynamics in the gas-phase is observed in the solution-phase suggesting that the dynamics are now driven by efficient E/Z isomerisation from the initially photoexcited 11ππ* state to S0.

Graphical abstract: Bottom-up excited state dynamics of two cinnamate-based sunscreen filter molecules

Supplementary files

Article information

Article type
Paper
Submitted
26 Jul 2016
Accepted
20 Sep 2016
First published
22 Sep 2016
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2016,18, 28140-28149

Bottom-up excited state dynamics of two cinnamate-based sunscreen filter molecules

Y. Peperstraete, M. Staniforth, L. A. Baker, N. D. N. Rodrigues, N. C. Cole-Filipiak, W. Quan and V. G. Stavros, Phys. Chem. Chem. Phys., 2016, 18, 28140 DOI: 10.1039/C6CP05205C

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