Berenbeim, Jacob A., Wong, Natalie G.K., Cockett, Martin C.R. orcid.org/0000-0001-5580-7408 et al. (4 more authors) (2020) Sodium cationization can disrupt the intramolecular hydrogen bond that mediates the sunscreen activity of oxybenzone. Physical Chemistry Chemical Physics. pp. 19522-19531. ISSN 1463-9084
Abstract
A key decay pathway by which organic sunscreen molecules dissipate harmful UV energy involves excited-state hydrogen atom transfer between proximal enol and keto functional groups. Structural modifications of this molecular architecture have the potential to block ultrafast decay processes, and hence promote direct excited-state molecular dissociation, profoundly affecting the efficiency of an organic sunscreen. Herein, we investigate the binding of alkali metal cations to a prototype organic sunscreen molecule, oxybenzone, using IR characterization. Mass-selective IR action spectroscopy was conducted at the free electron laser for infrared experiments, FELIX (600-1800 cm-1), on complexes of Na+, K+ and Rb+ bound to oxybenzone. The IR spectra reveal that K+ and Rb+ adopt binding positions away from the key OH intermolecular hydrogen bond, while the smaller Na+ cation binds directly between the keto and enol oxygens, thus breaking the intramolecular hydrogen bond. UV laser photodissociation spectroscopy was also performed on the series of complexes, with the Na+ complex displaying a distinctive electronic spectrum compared to those of K+ and Rb+, in line with the IR spectroscopy results. TD-DFT calculations reveal that the origin of the changes in the electronic spectra can be linked to rupture of the intramolecular bond in the sodium cationized complex. The implications of our results for the performance of sunscreens in mixtures and environments with high concentrations of metal cations are discussed.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © the Owner Societies 2020. |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Chemistry (York) |
Depositing User: | Pure (York) |
Date Deposited: | 02 Sep 2020 10:00 |
Last Modified: | 09 Jan 2025 05:24 |
Published Version: | https://doi.org/10.1039/D0CP03152F |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1039/D0CP03152F |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:165057 |
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Description: Sodium cationization can disrupt the intramolecular hydrogen bond that mediates the sunscreen activity of oxybenzone
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