UV filter 2‐ethylhexyl 4‐methoxycinnamate: a structure, energetic and UV–vis spectral analysis based on density functional theory

Miranda, Margarida S.; Silva, Luís Pinto da; Silva, Joaquim C. G. Esteves da

doi:10.1002/poc.3235

Cited by 27 publications

(29 citation statements)

References 45 publications

(61 reference statements)

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“…[44][45][46] This approach has been used routinely with good results in the study of ESPT reactions, [28,[47][48][49][50][51][52] and in the elucidation of other features of excited states. [53][54][55][56][57][58][59][60] Given this reasoning, the potential Franck-Condon curves were obtained by performing vertical excitation calculations on the ground-state reactions (Figure 3 a). Thus, the structures of Franck-Condon neutral enol oxyluciferin, and corresponding anions, are the same (Figure 2).…”

Section: Photoacidity Of the Enol Group Within The Franck-condon Apprmentioning

confidence: 99%

Theoretical Study of the Nontraditional Enol‐Based Photoacidity of Firefly Oxyluciferin

Silva

2014

ChemPhysChem

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A theoretical analysis of the enol-based photoacidity of oxyluciferin in water is presented. The basis for this phenomenon is found to be the hydrogen-bonding network that involves the conjugated photobase of oxyluciferin. The hydrogen-bonding network involving the enolate thiazole moiety is stronger than that of the benzothiazole phenolate moiety. Therefore, enolate oxyluciferin should be stabilized versus the phenolate anion. This difference in strength is attributed to the fact that the thiazole moiety has more potential hydrogen-bond acceptors near the proton donor atom than the benzothiazole moiety. Moreover, the phenol-based excited-state proton transfer leads to a decrease in the hydrogen-bond acceptor potential of the thiazole atoms. The ground-state enol-based acidity of oxyluciferin is also studied. This phenomenon can be explained by stabilization of the enolate anion through strengthening of a bond between water and the nitrogen atom of the thiazole ring, in an enol-based proton-transfer-dependent way.

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Section: Photoacidity Of the Enol Group Within The Franck-condon Apprmentioning

confidence: 99%

Theoretical Study of the Nontraditional Enol‐Based Photoacidity of Firefly Oxyluciferin

Silva

2014

ChemPhysChem

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“…[48,49] The strategy of using the Franck-Condon state to obtain information regarding the emissive state is routinely used with good results in a variety of topics. [50][51][52][53][54][55][56][57][58][59][60] The hydrogen atoms of the hydroxyl group of the three carboxylate luciferin anions were withdrawn in order to simulate the formation of the dianion species at acidic pH. [38] The resulting conformations of the Franck-Condon luciferin dianion at acidic and basic pH are presented in Figure 2.…”

Section: Watermentioning

confidence: 99%

A Theoretical Analysis of the Potential Role of π–π Stacking Interactions in the Photoprotolytic Cycle of Firefly Luciferin

Silva¹,

Silva²

2014

ChemPhysChem

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Firefly oxyluciferin is a photoacid that presents a pH-sensitive fluorescence, which results from pH-dependent changes on the conformation of self-aggregated π-π stacking complexes. Luciferin is a derivative of oxyluciferin with very similar fluorescence and photoacidic properties. This similarity indicates that luciferin is also expected to be able to form π-π stacking complexes, but no pH-sensitive fluorescence is found for this compound. Here, a theoretical approach is used to rationalize this finding. We have found that luciferin only forms π-π stacking complexes in the ground state at acidic pH. At basic pH and in the excited state, luciferin is present as a dianion. This species is not able to self-aggregate, owing to repulsive electrostatic interactions. Thus, this emissive species is not subject to π-π stacking interactions; this explains its pH-insensitive fluorescence.

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“…EHMC is unstable in light, commercial EHMC is in its initial trans ‐EHMC configuration that may change under UV light to cis ‐EHMC (Chatelain and Gabard, ; Miranda et al, ). The isomerisation of this compound by light is a relatively fast; the decrease of the sun protection factor (SPF) after 20 min may be more than 30% (Huong et al, ).…”

Section: Introductionmentioning

confidence: 99%

New probabilistic risk assessment of ethylhexyl methoxycinnamate: Comparing the genotoxic effects of trans‐ and cis‐EHMC

Nečasová

Bányiová

Literák

et al. 2016

Environmental Toxicology

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Ethylhexyl methoxycinnamate (EHMC) is a widely used UV filter present in a large number of personal care products (PCPs). Under normal conditions, EHMC occurs in a mixture of two isomers: trans-EHMC and cis-EHMC in a ratio of 99:1. When exposed to sunlight, the trans isomer is transformed to the less stable cis isomer and the efficiency of the UV filter is reduced. To date, the toxicological effects of the cis-EHMC isomer remain largely unknown. We developed a completely new method for preparing cis-EHMC. An EHMC technical mixture was irradiated using a UV lamp and 98% pure cis-EHMC was isolated from the irradiated solution using column chromatography. The genotoxic effects of the isolated cis-EHMC isomer and the nonirradiated trans-EHMC were subsequently measured using two bioassays (SOS chromotest and UmuC test). In the case of trans-EHMC, significant genotoxicity was observed using both bioassays at the highest concentrations (0.5 - 4 mg mL ). In the case of cis-EHMC, significant genotoxicity was only detected using the UmuC test at concentrations of 0.25 - 1 mg mL . Based on these results, the NOEC was calculated for both cis- and trans-EHMC, 0.038 and 0.064 mg mL , respectively. Risk assessment of dermal, oral and inhalation exposure to PCPs containing EHMC was carried out for a female population using probabilistic simulation and by using Quantitative in vitro to in vivo extrapolation (QIVIVE). The risk of cis-EHMC was found to be ∼1.7 times greater than trans-EHMC. In the case of cis-EHMC, a hazard index of 1 was exceeded in the 92nd percentile. Based on the observed differences between the isomers, EHMC application in PCPs requires detailed reassessment. Further exploration of the toxicological effects and properties of cis-EHMC is needed in order to correctly predict risks posed to humans and the environment. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 569-580, 2017.

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UV filter 2‐ethylhexyl 4‐methoxycinnamate: a structure, energetic and UV–vis spectral analysis based on density functional theory

Cited by 27 publications

References 45 publications

Theoretical Study of the Nontraditional Enol‐Based Photoacidity of Firefly Oxyluciferin

Theoretical Study of the Nontraditional Enol‐Based Photoacidity of Firefly Oxyluciferin

A Theoretical Analysis of the Potential Role of π–π Stacking Interactions in the Photoprotolytic Cycle of Firefly Luciferin

New probabilistic risk assessment of ethylhexyl methoxycinnamate: Comparing the genotoxic effects of trans‐ and cis‐EHMC

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