Substituent position effects on sunscreen photodynamics: A closer look at methyl anthranilate

Rodrigues, Natércia d. N.; Cole-Filipiak, Neil C.; Turner, Matthew S.; Krokidi, Konstantina M.; Thornton, Georgia L; Richings, Gareth W.; Hine, Nicholas; Stavros, Vasilios G.

doi:10.1016/j.chemphys.2018.08.001

Cited by 5 publications

(17 citation statements)

References 51 publications

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“…More recently, TR-IY studies have sought to determine whether altering the location of the amino group, and thus removing the intramolecular hydrogen bond formed with the ester group, would improve the photodynamics for use in sunscreens [188].…”

Section: Gas-phase Spectroscopy Studiesmentioning

confidence: 99%

Section: Gas-phase Spectroscopy Studiesmentioning

confidence: 99%

“…Rodrigues et al [188] note that the pump pulse will excite both rotamers of m-MA (shown in Figure 3(a)). In comparison, the rate of decay for the para species is much slower than the meta species [188] (ca. Rodrigues et al [188] to an inaccessible CI, the existence of which was attained using computational methods [188].…”

Section: Gas-phase Spectroscopy Studiesmentioning

confidence: 99%

“…Overall, owing to its faster excited state decay and lower quantum yield of fluorescence than o-MA (25 ± 5% compared to > 60% [188,190]), plus the presence of at least one accessible conical intersection of a prefulvenic nature, m-MA is a more appropriate choice for sunscreen molecular design. Examples of prefulvenic conical intersections, which involve distortion of the benzene ring, have been explored in detail in separate publications [191][192][193][194].…”

Section: Gas-phase Spectroscopy Studiesmentioning

confidence: 99%

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Applications of ultrafast spectroscopy to sunscreen development, from first principles to complex mixtures

Holt

Stavros

2019

International Reviews in Physical Chemistry

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Section: Gas-phase Spectroscopy Studiesmentioning

confidence: 99%

Section: Gas-phase Spectroscopy Studiesmentioning

confidence: 99%

Section: Gas-phase Spectroscopy Studiesmentioning

confidence: 99%

Section: Gas-phase Spectroscopy Studiesmentioning

confidence: 99%

See 2 more Smart Citations

Applications of ultrafast spectroscopy to sunscreen development, from first principles to complex mixtures

Holt

Stavros

2019

International Reviews in Physical Chemistry

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“…This allows us to monitor how the absorbance of the anion varies with wavelength, while simultaneously measuring the production of any photoproducts . Our laser‐based approach is in the spirit of a number of recent studies where advanced spectroscopic techniques have been applied to sunscreen molecules under highly‐controlled conditions …”

Section: Introductionmentioning

confidence: 99%

Direct Observation of Photochemical Free Radical Production from the Sunscreen 2‐Phenylbenzimidazole‐5‐Sulfonic Acid via Laser‐Interfaced Mass Spectrometry

2019

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The common sunscreen molecule 2-phenylbenzimidazole-5sulfonic acid (PBSA) is studied in its gas-phase deprotonated form ([PBSA-H] À ) for the first time as an important step in achieving a better understanding of its behavior as a photosensitizer. UV laser-interfaced mass spectrometry is employed, revealing that [PBSA-H] À photofragments into three ionic products (m/z 208, 193, and 80) with distinctive wavelengthdependent production profiles. Both the m/z 208 and 80 channels produce associated neutral free radical species.showing that its hot ground-state dissociates only into m/z 193 (statistical fragment). Therefore, the m/z 208 and 80 fragments which are produced strongly through the UVA/UVB are characterized as non-statistical photofragments associated with non-ergodic excited-state decay. Our observation of nonstatistical photofragments reveal that [PBSA-H] À is not behaving as a model sunscreen molecule. Further, our results indicate that the T 1 state, associated with photosensitization, decays with direct free radical production.[a] N.

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New Generation UV-A Filters: Understanding Their Photodynamics on a Human Skin Mimic

Abiola

Rodrigues

et al. 2020

J. Phys. Chem. Lett.

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The sparsity of efficient commercial ultraviolet-A (UV-A) filters is a major challenge toward developing effective broadband sunscreens with minimal human-and eco-toxicity. To combat this, we have designed a new class of Meldrum-based phenolic UV-A filters. We explore the ultrafast photodynamics of coumaryl Meldrum, CMe, and sinapyl Meldrum (SMe), both in an industry-standard emollient and on a synthetic skin mimic, using femtosecond transient electronic and vibrational absorption spectroscopies and computational simulations. Upon photoexcitation to the lowest excited singlet state (S 1 ), these Meldrum-based phenolics undergo fast and efficient nonradiative decay to repopulate the electronic ground state (S 0 ). We propose an initial ultrafast twisted intramolecular charge-transfer mechanism as these systems evolve out of the Franck−Condon region toward an S 1 /S 0 conical intersection, followed by internal conversion to S 0 and subsequent vibrational cooling. Importantly, we correlate these findings to their long-term photostability upon irradiation with a solar simulator and conclude that these molecules surpass the basic requirements of an industry-standard UV filter.

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Substituent position effects on sunscreen photodynamics: A closer look at methyl anthranilate

Cited by 5 publications

References 51 publications

Applications of ultrafast spectroscopy to sunscreen development, from first principles to complex mixtures

Applications of ultrafast spectroscopy to sunscreen development, from first principles to complex mixtures

Direct Observation of Photochemical Free Radical Production from the Sunscreen 2‐Phenylbenzimidazole‐5‐Sulfonic Acid via Laser‐Interfaced Mass Spectrometry

New Generation UV-A Filters: Understanding Their Photodynamics on a Human Skin Mimic

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