1
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Shimray SA, Ningthoujam A, Khaidem DKS, Chipem FAS. Theoretical studies on the photo protective mechanism of curcuminoids. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 305:123449. [PMID: 37774584 DOI: 10.1016/j.saa.2023.123449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/16/2023] [Accepted: 09/20/2023] [Indexed: 10/01/2023]
Abstract
In this work, the deactivation pathways of curcuminoids after photoexcitation was studied by employing density functional theory to explore their UVA radiation screening capacity. A comprehensive computational characterization of the excited-state processes of curcumin, demethoxycurcumin, and bis-demethoxycurcumin was done. The molecules exist in diketo and enol forms which are in equilibrium and interconvertible through keto-enol tautomerism. The enolic forms of each of the studied molecules have eight geometric cis-trans isomers as a result of torsion rotation about three different carbon-carbon double bonds across the aliphatic chain. For each geometric isomer, sixteen possible rotamers are found to exist due to rotation about five different carbon-carbon single bond rotations, also across the skeleton of the aliphatic chain. Upon photoexcitation, the studied molecules follow three main pathways of radiationless decay: (a) rotamerism and interconversion between rotamers of comparable energies which are in equilibrium, (b) interconversion between the cis-trans geometrical isomers where an efficient vibrational relaxation path is formed at ∼90° during torsion rotation about carbon-carbon double bond, and (c) excited state intramolecular proton transfer in a single O-H stretching vibration through a cyclic intramolecular hydrogen bonded ring formed at the centre of the molecule giving back the original structure. The absorption and emission spectra of the molecules were also simulated where the theoretically obtained absorption and emission maxima are close to the reported experimental values.
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Affiliation(s)
- Sophy A Shimray
- Department of Chemistry, Manipur University, Canchipur 795 003, India
| | - Amar Ningthoujam
- Department of Chemistry, Manipur University, Canchipur 795 003, India
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2
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Li Y, He Y, Lam CH, Nah T. Environmental photochemistry of organic UV filter butyl methoxydibenzoylmethane: Implications for photochemical fate in surface waters. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 839:156145. [PMID: 35613640 DOI: 10.1016/j.scitotenv.2022.156145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 05/16/2022] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
With the widespread use of sunscreen and other personal care products, organic ultraviolet filters (OUVFs) have become widely detected in the aquatic environment. Direct and indirect photolysis are important transformation pathways of OUVFs in aquatic environments, so their transformation products (TPs) are also chemicals of concern. Butyl methoxydibenzoylmethane (BMDBM) is one of the most commonly used OUVFs worldwide due to its ability to absorb ultraviolet light across a wide range of wavelengths, and it is ubiquitously detected in aquatic environments. In this study, we investigated the photodegradation of BMDBM through direct photolysis and hydroxyl radical (•OH) photooxidation. TPs were identified using ultrahigh performance liquid chromatography-high resolution mass spectrometry, and reaction mechanisms were proposed. Our results showed that the photodegradation rates for both enol and keto tautomer forms of BMDBM during direct photolysis and •OH photooxidation were similar. The formation of TPs resulted from α-cleavage and decarbonylation reactions involving the keto form of BMDBM. Comparisons of the kinetic data and TPs revealed that the direct photolysis mechanism was a significant sink for BMDBM even during •OH photooxidation. Evaluations of environmental properties based on the predicted physicochemical properties of BMDBM and TPs suggests that some of the TPs will have higher mobility than BMDBM. The quantitative structure-activity relationship (QSAR) approach was used to evaluate the ecotoxicity of BMDBM and the identified TPs. Most TPs were found to be less ecotoxic than BMDBM; however, TPs that had a diphenyl ring structure could be more ecotoxic than BMDBM. Overall, this study provides new insights into the photochemical behavior and ecotoxicity of BMDBM and its TPs, which are important for assessing the fate, persistence, accumulation, and adverse impacts of these compounds in aquatic environments.
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Affiliation(s)
- Yitao Li
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China.
| | - Yuhe He
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China.
| | - Chun Ho Lam
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China.
| | - Theodora Nah
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, China.
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3
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Xie BB, Tang XF, Liu XY, Chang XP, Cui G. Mechanistic photophysics and photochemistry of unnatural bases and sunscreen molecules: insights from electronic structure calculations. Phys Chem Chem Phys 2021; 23:27124-27149. [PMID: 34849517 DOI: 10.1039/d1cp03994f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photophysics and photochemistry are basic subjects in the study of light-matter interactions and are ubiquitous in diverse fields such as biology, energy, materials, and environment. A full understanding of mechanistic photophysics and photochemistry underpins many recent advances and applications. This contribution first provides a short discussion on the theoretical calculation methods we have used in relevant studies, then we introduce our latest progress on the mechanistic photophysics and photochemistry of two classes of molecular systems, namely unnatural bases and sunscreens. For unnatural bases, we disclose the intrinsic driving forces for the ultrafast population to reactive triplet states, impacts of the position and degree of chalcogen substitutions, and the effects of complex environments. For sunscreen molecules, we reveal the photoprotection mechanisms that dissipate excess photon energy to the surroundings by ultrafast internal conversion to the ground state. Finally, relevant theoretical challenges and outlooks are discussed.
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Affiliation(s)
- Bin-Bin Xie
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Xiu-Fang Tang
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Xiang-Yang Liu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu, Sichuan, 610068, China
| | - Xue-Ping Chang
- College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang 464000, P. R. China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China.
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4
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Holt EL, Rodrigues NDN, Cebrián J, Stavros VG. Determining the photostability of avobenzone in sunscreen formulation models using ultrafast spectroscopy. Phys Chem Chem Phys 2021; 23:24439-24448. [PMID: 34694312 DOI: 10.1039/d1cp03610f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Avobenzone is an ultraviolet (UV) filter that is often included in sunscreen formulations despite its lack of photostability. Its inclusion is necessary due to few existing alternatives for photoprotection in the UVA region (320-400 nm). To better understand and predict the photostability of avobenzone, ultrafast transient electronic absorption spectroscopy (TEAS) has been used to study the effects of solvent (including emollients), concentration and skin surface temperature on its excited-state relaxation mechanism, following photoexcitation with UVA radiation (∼350 nm). Subtle differences between the excited-state lifetimes were found between the systems, but the TEAS spectral features were qualitatively the same for all solution and temperature combinations. Alongside TEAS measurements, UV filter/emollient blends containing avobenzone were irradiated using simulated solar light and their degradation tracked using steady-state UV-visible spectroscopy. Sun protection factor (SPF) and UVA protection factor (UVA-PF) assessments were also carried out on representative oil phases (higher concentration blends), which could be used to formulate oil-in-water sunscreens. It was found that there was an apparent concentration dependence on the long-term photoprotective efficacy of these mixtures, which could be linked to the ultrafast photodynamics by the presence of a ground-state bleach offset. This combination of techniques shows potential for correlating long-term behaviours (minutes to hours) of avobenzone with its ultrafast photophysics (femtoseconds to nanoseconds), bridging the gap between fundamental photophysics/photochemistry and commercial sunscreen design.
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Affiliation(s)
- Emily L Holt
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK. .,Molecular Analytical Science Centre for Doctoral Training, Senate House, University of Warwick, Coventry, CV4 7AL, UK
| | - Natércia D N Rodrigues
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK. .,Lubrizol Life Science Beauty, Calle Isaac Peral, 17 Pol. Ind. Camí Ral, 08850 Barcelona, Spain
| | - Juan Cebrián
- Lubrizol Life Science Beauty, Calle Isaac Peral, 17 Pol. Ind. Camí Ral, 08850 Barcelona, Spain
| | - Vasilios G Stavros
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
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5
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Wu Z, Wang M, Guo Y, Ji F, Wang C, Wang S, Zhang J, Wang Y, Zhang S, Jin B, Zhao G. Nonadiabatic Dynamics Mechanism of Chalcone Analogue Sunscreen FPPO-HBr: Excited State Intramolecular Proton Transfer Followed by Conformation Twisting. J Phys Chem B 2021; 125:9572-9578. [PMID: 34433282 DOI: 10.1021/acs.jpcb.1c05809] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Nowadays, traditional sunscreen molecules face many adverse problems: single energy relaxation pathway, lack of adequate UVA light protection, and therefore no longer meeting the growing demand for UVA protection. In this work, we reported a novel sunscreen molecule (E)-3-(5-bromofuran-2-yl)-1-(2-hydroxyphenyl)prop-2-en-1-one (hereinafter referred to as FPPO-HBr) which tackled adverse problems of traditional sunscreen molecules as single energy relaxation pathway, lacking effective UVA light protection. Various nonradiative pathways were proposed and verified by combining the steady-state and femtosecond transient absorption (FTA) spectroscopy and theoretical calculation. Upon UV excitation, the FPPO-HBr mainly decays via excited-state intramolecular proton transfer (ESIPT) followed by conformation twist in ultrafast manner. Importantly, 1H NMR spectra proved that the FPPO-HBr could not undergo trans-cis photoisomerization. Additionally, excellent photostability was also observed for newly synthesized FPPO-HBr. The current work could provide new perspectives for sunscreen molecules synthesis and mechanism.
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Affiliation(s)
- Zibo Wu
- MeChem Group, Molecular Dynamic Chemistry Center, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, National Demonstration Center for Experimental Chemistry & Chemical engineering Education, School of Science, Tianjin University, Tianjin 300354, China
| | - Mengqi Wang
- MeChem Group, Molecular Dynamic Chemistry Center, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, National Demonstration Center for Experimental Chemistry & Chemical engineering Education, School of Science, Tianjin University, Tianjin 300354, China
| | - Yurong Guo
- MeChem Group, Molecular Dynamic Chemistry Center, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, National Demonstration Center for Experimental Chemistry & Chemical engineering Education, School of Science, Tianjin University, Tianjin 300354, China.,New Sunscreens Development and UV Photoprotection Research Center, Tianjin ChenyinSTI Co., Ltd., Xinghua Road at Xeda, Tianjin 300385, China
| | - Feixiang Ji
- MeChem Group, Molecular Dynamic Chemistry Center, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, National Demonstration Center for Experimental Chemistry & Chemical engineering Education, School of Science, Tianjin University, Tianjin 300354, China
| | - Chao Wang
- MeChem Group, Molecular Dynamic Chemistry Center, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, National Demonstration Center for Experimental Chemistry & Chemical engineering Education, School of Science, Tianjin University, Tianjin 300354, China
| | - Shiping Wang
- MeChem Group, Molecular Dynamic Chemistry Center, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, National Demonstration Center for Experimental Chemistry & Chemical engineering Education, School of Science, Tianjin University, Tianjin 300354, China
| | - Jingran Zhang
- MeChem Group, Molecular Dynamic Chemistry Center, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, National Demonstration Center for Experimental Chemistry & Chemical engineering Education, School of Science, Tianjin University, Tianjin 300354, China.,New Sunscreens Development and UV Photoprotection Research Center, Tianjin ChenyinSTI Co., Ltd., Xinghua Road at Xeda, Tianjin 300385, China
| | - Ye Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science, Chinese Academy of Sciences, Wuhan 430071, China
| | - Song Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science, Chinese Academy of Sciences, Wuhan 430071, China
| | - Bing Jin
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science, Chinese Academy of Sciences, Wuhan 430071, China
| | - Guangjiu Zhao
- MeChem Group, Molecular Dynamic Chemistry Center, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, National Demonstration Center for Experimental Chemistry & Chemical engineering Education, School of Science, Tianjin University, Tianjin 300354, China
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6
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Murphy RB, Staton J, Rawal A, Darwish TA. The effect of deuteration on the keto-enol equilibrium and photostability of the sunscreen agent avobenzone. Photochem Photobiol Sci 2020; 19:1410-1422. [PMID: 32966538 DOI: 10.1039/d0pp00265h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The remarkable properties of deuterium have led to many exciting and favourable results in enhancing material properties, for applications in the physical, medical, and biological sciences. Deuterated isotopologues of avobenzone, a sunscreen active ingredient, were synthesised to examine for any changes to the equilibrium between the diketone and enol isomers, as well as their UV photostability and photoprotective properties. Prior to UV irradiation, deuteration of the diketone methylene/enol moiety (i.e. avobenzone-d2) led to an increase in the % diketone compared to non-deuterated, determined by 1H NMR experiments in CDCl3 and C6D12. This can be rationalised from two angles; mechanistically by a deuterium kinetic isotope effect for the CH vs. CD abstraction step during tautomerisation from the diketone to the enol, and a weaker chelating hydrogen bond for the enol when deuterated allowing increased equilibration to the diketone. Avobenzone-d2 was further examined by solid state 13C NMR. The higher % diketone for avobenzone-d2 was postulated to favour increased photodegradation by a non-reversible pathway. This was investigated by UV irradiation of the avobenzone isotopologues in C6D12, both in real time in situ within the NMR by fibre optic cable as well as ex situ using sunlight. An increase in the relative amount of photoproducts for avobenzone-d2 compared to non-deuterated was observed by 1H NMR upon UV irradiation ex situ. Overall, the study demonstrates that deuteration can be applied to alter complex equilibria, and has potential to be manifested as changes to the properties and behaviour of materials.
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Affiliation(s)
- Rhys B Murphy
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia.
| | - John Staton
- Eurofins Dermatest, 20 King Street, Rockdale, New South Wales 2216, Australia
| | - Aditya Rawal
- Nuclear Magnetic Resonance Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, Australia
| | - Tamim A Darwish
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia.
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7
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Berenbeim JA, Wong NGK, Cockett MCR, Berden G, Oomens J, Rijs AM, Dessent CEH. Unravelling the Keto-Enol Tautomer Dependent Photochemistry and Degradation Pathways of the Protonated UVA Filter Avobenzone. J Phys Chem A 2020; 124:2919-2930. [PMID: 32208697 PMCID: PMC7168606 DOI: 10.1021/acs.jpca.0c01295] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
Avobenzone (AB) is
a widely used UVA filter known to undergo irreversible
photodegradation. Here, we investigate the detailed pathways by which
AB photodegrades by applying UV laser-interfaced mass spectrometry
to protonated AB ions. Gas-phase infrared multiple-photon dissociation
(IRMPD) spectra obtained with the free electron laser for infrared
experiments, FELIX, (600–1800 cm–1) are also
presented to confirm the geometric structures. The UV gas-phase absorption
spectrum (2.5–5 eV) of protonated AB contains bands that correspond
to selective excitation of either the enol or diketo forms, allowing
us to probe the resulting, tautomer-dependent photochemistry. Numerous
photofragments (i.e., photodegradants) are directly identified for
the first time, with m/z 135 and
161 dominating, and m/z 146 and
177 also appearing prominently. Analysis of the production spectra
of these photofragments reveals that that strong enol to keto photoisomerism
is occurring, and that protonation significantly disrupts the stability
of the enol (UVA active) tautomer. Close comparison of fragment ion
yields with the TD-DFT-calculated absorption spectra give detailed
information on the location and identity of the dissociative excited
state surfaces, and thus provide new insight into the photodegradation
pathways of avobenzone, and photoisomerization of the wider class
of β-diketone containing molecules.
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Affiliation(s)
- Jacob A Berenbeim
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
| | - Natalie G K Wong
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
| | - Martin C R Cockett
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
| | - Giel Berden
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, Nijmegen, 6500 HC, The Netherlands
| | - Jos Oomens
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, Nijmegen, 6500 HC, The Netherlands
| | - Anouk M Rijs
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, Nijmegen, 6500 HC, The Netherlands
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8
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Chan CTL, Ma C, Chan RCT, Ou HM, Xie HX, Wong AKW, Wang ML, Kwok WM. A long lasting sunscreen controversy of 4-aminobenzoic acid and 4-dimethylaminobenzaldehyde derivatives resolved by ultrafast spectroscopy combined with density functional theoretical study. Phys Chem Chem Phys 2020; 22:8006-8020. [PMID: 32239002 DOI: 10.1039/c9cp07014a] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
4-Aminobenzoic acid (PABA) is one of the earliest patented and most commonly used sunscreen components. There is however a long-lasting controversy on its photo-protective efficacy owing to the lack of information on its protolytic equilibrium and photo-dynamics after absorption of ultraviolet radiation in physiologically relevant aqueous solution. The excitation dynamics in water also remains largely unknown for analogs of PABA such as 4-dimethylaminoacetophenone (DMAAP) and 4-dimethylaminobenzaldehyde (DMABA) which are recognized as prototypes for photo-induced twisted intramolecular charge transfer (TICT). Herein we report a combined application of femtosecond broadband time-resolved fluorescence and transient absorption coupled with density functional theoretical study for PABA, DMAAP, and DMABA under several solvent conditions with representative properties in terms of the pH, polarity and hydrogen bonding capacity. The results we gained demonstrate that, in a neutral aqueous solution, PABA taking the deprotonated anion form in the ground state undergoes rapid protonation after excitation, producing excited state species in the neutral form that may shift effectively by intersystem crossing (ISC) to the long-lasting triplet state capable of damaging nucleic acids. This provides evidence at the molecular level for the detrimental effect of PABA if used as a sunscreen ingredient. In contrast, our investigation on DMAAP and DMABA unveils an unusual solvent controlled deactivation dynamics rendered by the participation of the carbonyl oxygen associated nOπ* state featuring energy and structure strongly responsive to solvent properties. In particular, these molecules in water exhibit solute-solvent hydrogen bonding at the sites of the carbonyl oxygen and the amino nitrogen which is, respectively, weakened and strengthened after the excitation, leading to state reversal and formation of a nOπ* state with a peculiar non-planar structure. This quenches strongly the excitation, eliminates the TICT, suppresses the ISC and opens up the otherwise inaccessible internal conversion (IC) to account for ∼80% of the entire deactivation. The IC, observed to proceed at a rate of ∼2.5 ps, allows the effective recovery of the ground state, providing substantial protection against ultraviolet irradiation. Moreover, the revelation of highly solvent sensitive fluorescence emission from DMABA and DMAAP implies the potential application of these molecules as the functional element in the design of sensory materials for probing the polarity and hydrogen bonding character of the surrounding environment.
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Affiliation(s)
- Chris Tsz-Leung Chan
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, P. R. China.
| | - Chensheng Ma
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, P. R. China.
| | - Ruth Chau-Ting Chan
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, P. R. China.
| | - Hui-Min Ou
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, P. R. China.
| | - Han-Xin Xie
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, P. R. China.
| | - Allen Ka-Wa Wong
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, P. R. China.
| | - Ming-Liang Wang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, P. R. China.
| | - Wai-Ming Kwok
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, P. R. China.
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9
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Hanson KM, Cutuli M, Rivas T, Antuna M, Saoub J, Tierce NT, Bardeen CJ. Effects of solvent and micellar encapsulation on the photostability of avobenzone. Photochem Photobiol Sci 2020; 19:390-398. [DOI: 10.1039/c9pp00483a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Avobenzone, the only UVA-absorbing molecule approved for use in sunscreens by the FDA, degrades to its diketone structure under UV light. We found that this photoisomerization is effectively prevented when avobenzone is sequestered in micelles.
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Affiliation(s)
- Kerry M. Hanson
- Department of Chemistry
- University of California
- Riverside
- Riverside
- USA
| | - Miles Cutuli
- Department of Chemistry
- University of California
- Riverside
- Riverside
- USA
| | - Tiffany Rivas
- Department of Chemistry
- University of California
- Riverside
- Riverside
- USA
| | - Miranda Antuna
- Department of Chemistry
- University of California
- Riverside
- Riverside
- USA
| | - Jessica Saoub
- Department of Chemistry
- University of California
- Riverside
- Riverside
- USA
| | - Nathan T. Tierce
- Department of Chemistry
- University of California
- Riverside
- Riverside
- USA
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10
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Milovanović B, Stanković IM, Petković M, Etinski M. Elucidating Solvent Effects on Strong Intramolecular Hydrogen Bond: DFT-MD Study of Dibenzoylmethane in Methanol Solution. Chemphyschem 2019; 20:2852-2859. [PMID: 31544323 DOI: 10.1002/cphc.201900704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 08/31/2019] [Indexed: 11/10/2022]
Abstract
The dynamic aspect of solvation plays a crucial role in determining properties of strong intramolecular hydrogen bonds since solvent fluctuations modify instantaneous hydrogen-bonded proton transfer barriers. Previous studies pointed out that solvent-solute interactions in the first solvation shell govern the position of the proton but the ability of the electric field due to other solvent molecules to localize the proton remains an important issue. In this work, we examine the structure of the O-H⋅⋅⋅O intramolecular hydrogen bond of dibenzoylmethane in methanol solution by employing density functional theory-based molecular dynamics and quantum chemical calculations. Our computations showed that homogeneous electric fields with intensities corresponding to those found in polar solvents are able to considerably alter the proton transfer barrier height in the gas phase. In methanol solution, the proton position is correlated with the difference in electrostatic potentials on the oxygen atoms of dibenzoylmethane even when dibenzoylmethane-methanol hydrogen bonding is lacking. On a timescale of our simulation, the hydrogen bonding and solvent electrostatics tend to localize the proton on different oxygen atoms. These findings provide an insight into the importance of the solvent electric field on the structure of a strong intramolecular hydrogen bond.
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Affiliation(s)
- Branislav Milovanović
- Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000, Belgrade, Serbia
| | | | - Milena Petković
- Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000, Belgrade, Serbia
| | - Mihajlo Etinski
- Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000, Belgrade, Serbia
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11
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Kojić M, Lyskov I, Milovanović B, Marian CM, Etinski M. The UVA response of enolic dibenzoylmethane: beyond the static approach. Photochem Photobiol Sci 2019; 18:1324-1332. [DOI: 10.1039/c9pp00005d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The nπ* and ππ* states of dibenzoylmethane are vibronically coupled and their crossing occurs during the excited-state intramolecular proton transfer.
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Affiliation(s)
- Marko Kojić
- Faculty of Physical Chemistry
- University of Belgrade
- 11000 Belgrade
- Serbia
| | - Igor Lyskov
- Chemical and Quantum Physics Group
- ARC Centre of Excellence in Exciton Science
- School of Science
- RMIT University
- Melbourne
| | | | - Christel M. Marian
- Institute of Theoretical and Computational Chemistry
- Heinrich Heine University Düsseldorf
- D-40225 Düsseldorf
- Germany
| | - Mihajlo Etinski
- Faculty of Physical Chemistry
- University of Belgrade
- 11000 Belgrade
- Serbia
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12
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Ma C, Chan CTL, Chan RCT, Wong AKW, Chung BPY, Kwok WM. Photoprotection or photodamage: a direct observation of nonradiative dynamics from 2-ethylhexyl 4-dimethylaminobenzoate sunscreen agent. Phys Chem Chem Phys 2018; 20:24796-24806. [PMID: 30229763 DOI: 10.1039/c8cp04447c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Apart from being an analogue of the prototype for photoinduced intramolecular charge transfer (ICT), 2-ethylhexyl 4-dimethylaminobenzoate (EHDMABA) is also one of the earliest patented and most commonly used sunscreen components. There is, however, little documented information about the photophysics and factors affecting the photophysics of this molecule. Such information is of importance for both the understanding of the ICT reaction and assessing the underlying process of photoprotection, especially in view of the "sunscreen controversy" that has arisen from the contrasting in vivo vs. in vitro photobiological results on this and related UV filters. We report herein a femtosecond broadband time-resolved fluorescence (fs-TRF), complemented by transient absorption (fs-TA) to allow a full probe of the excited state cascades for EHDMABA and two of its derivatives in solvents of varied properties. The results provide direct evidence for a nearly solvent independent inner sphere ICT reaction occurring on the sub-picosecond time scale, and an ensuing solvent dictated deactivation of the ICT state. The ICT state in the aprotic solvent acetonitrile decayed solely through the intrinsic intersystem crossing (ISC) to produce a potentially harmful triplet excited state. In the protic solvent, the solvation and formation of ICT-induced solute-solvent hydrogen (H)-bonding opened the originally inaccessible internal conversion (IC) channel of the ICT state, leading to the rapid reformation of the ground state molecule with a unitary efficiency in the aqueous solution. This H-bonding-mediated IC restrained or eliminated the intrinsic ISC, providing a mechanism at the molecular level for the benign dissipation of the electronic excitation. The precise rate of IC was observed to vary with the alkoxy substituent and its efficiency was affected by the H-bonding capacity of the solvent. The findings of this work demonstrate the pivotal role of the microenvironment and the direct participation of solvent molecules through H-bonding in drastically altering the nonradiative dynamics and promoting or inhibiting photostability and photoprotection. This may assist in developing next-generation UV filters and help in improving formulation design for the optimal efficacy of sunscreen products. The pronounced H-bonding-induced fluorescence quenching and variation in the fluorescence wavelength imply that these molecules may also serve as a sensitive fluorescence probe for the H-bonding properties of the microenvironment.
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Affiliation(s)
- Chensheng Ma
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, P. R. China.
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13
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Etinski M, Ensing B. Puzzle of the Intramolecular Hydrogen Bond of Dibenzoylmethane Resolved by Molecular Dynamics Simulations. J Phys Chem A 2018; 122:5945-5954. [DOI: 10.1021/acs.jpca.8b01930] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mihajlo Etinski
- Faculty of Physical Chemistry, University of Belgrade Studentski trg 12-16 11000 Belgrade, Serbia
| | - Bernd Ensing
- Van ’t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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14
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Tautomerism of 4-phenyl-2,4-dioxobutanoic acid. Insights from pH ramping NMR study and quantum chemical calculations. Struct Chem 2017. [DOI: 10.1007/s11224-017-1039-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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15
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Baker LA, Greenough SE, Stavros VG. A Perspective on the Ultrafast Photochemistry of Solution-Phase Sunscreen Molecules. J Phys Chem Lett 2016; 7:4655-4665. [PMID: 27791379 DOI: 10.1021/acs.jpclett.6b02104] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Sunscreens are one of the most common ways of providing on-demand additional photoprotection to the skin. Ultrafast transient absorption spectroscopy has recently proven to be an invaluable tool in understanding how the components of commercial sunscreen products display efficient photoprotection. Important examples of how this technique has unravelled the photodynamics of common components are given in this Perspective, and some of the remaining unanswered questions are discussed.
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Affiliation(s)
- Lewis A Baker
- Department of Chemistry, University of Warwick , Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
| | - Simon E Greenough
- Department of Chemistry, University of Sheffield , Sheffield S3 7HF, United Kingdom
| | - Vasilios G Stavros
- Department of Chemistry, University of Warwick , Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
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