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Abiola TT, Rioux B, Johal S, Mention MM, Brunissen F, Woolley JM, Allais F, Stavros VG. Insight into the Photodynamics of Photostabilizer Molecules. J Phys Chem A 2022; 126:8388-8397. [DOI: 10.1021/acs.jpca.2c05580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Temitope T. Abiola
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7ALUnited Kingdom
| | - Benjamin Rioux
- URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech, 51110, Pomacle, France
| | - Sharanjit Johal
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7ALUnited Kingdom
| | - Matthieu M. Mention
- URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech, 51110, Pomacle, France
| | - Fanny Brunissen
- URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech, 51110, Pomacle, France
| | - Jack M. Woolley
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7ALUnited Kingdom
| | - Florent Allais
- URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech, 51110, Pomacle, France
| | - Vasilios G. Stavros
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7ALUnited Kingdom
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2
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Mansoor A, Khurshid Z, Khan MT, Mansoor E, Butt FA, Jamal A, Palma PJ. Medical and Dental Applications of Titania Nanoparticles: An Overview. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:nano12203670. [PMID: 36296859 PMCID: PMC9611494 DOI: 10.3390/nano12203670] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 10/08/2022] [Accepted: 10/09/2022] [Indexed: 05/25/2023]
Abstract
Currently, titanium oxide (TiO2) nanoparticles are successfully employed in human food, drugs, cosmetics, advanced medicine, and dentistry because of their non-cytotoxic, non-allergic, and bio-compatible nature when used in direct close contact with the human body. These NPs are the most versatile oxides as a result of their acceptable chemical stability, lower cost, strong oxidation properties, high refractive index, and enhanced aesthetics. These NPs are fabricated by conventional (physical and chemical) methods and the latest biological methods (biological, green, and biological derivatives), with their advantages and disadvantages in this epoch. The significance of TiO2 NPs as a medical material includes drug delivery release, cancer therapy, orthopedic implants, biosensors, instruments, and devices, whereas their significance as a dental biomaterial involves dentifrices, oral antibacterial disinfectants, whitening agents, and adhesives. In addition, TiO2 NPs play an important role in orthodontics (wires and brackets), endodontics (sealers and obturating materials), maxillofacial surgeries (implants and bone plates), prosthodontics (veneers, crowns, bridges, and acrylic resin dentures), and restorative dentistry (GIC and composites).
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Affiliation(s)
- Afsheen Mansoor
- Department of Dental Material Sciences, School of Dentistry, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad 44080, Pakistan
| | - Zohaib Khurshid
- Department of Prosthodontics and Dental Implantology, College of Dentistry, King Faisal University, Al-Ahsa 31982, Saudi Arabia;
| | - Muhammad Talal Khan
- Department of Dental Biomaterials, Bakhtawar Amin Medical and Dental College, Multan 60650, Pakistan;
| | - Emaan Mansoor
- Islamic International Dental College, Riphah International University, Islamabad 44000, Pakistan;
| | - Faaz Ahmad Butt
- Department of Materials Engineering, NED University of Engineering & Technology, Karachi 74200, Pakistan;
| | - Asif Jamal
- Department of Microbiology, Quaid-i-Azam University, Islamabad 45320, Pakistan;
| | - Paulo J. Palma
- Center for Innovation and Research in Oral Sciences (CIROS), Faculty of Medicine, University of Coimbra, 3000-075 Coimbra, Portugal
- Institute of Endodontics, Faculty of Medicine, University of Coimbra, 3000-075 Coimbra, Portugal
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3
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Mubeen M, Khalid MA, Gul T, Mukhtar M, Ul-Hamid A, Iqbal A. Cu-Enhanced Efficient Förster Resonance Energy Transfer in PBSA Sunscreen-Associated Ternary Cu x Cd 1-x S Quantum Dots. ACS OMEGA 2022; 7:35014-35022. [PMID: 36211065 PMCID: PMC9535639 DOI: 10.1021/acsomega.2c03729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 09/08/2022] [Indexed: 06/16/2023]
Abstract
Quantum dots (QDs) are semiconducting nanocrystals that exhibit size- and composition-dependent optical and electronic properties. Recently, Cu-based II-VI ternary Cu x Cd1-x S (CCS) QDs have emerged as a promising class of QDs as compared to their binary counterparts (CuS and CdS). Herein, a series of ternary CCS QDs are synthesized by changing the molar concentration of Cu2+ ions only keeping the 1:1 ratio of the stoichiometric mixture of Cd2+ and S2-. These CCS QDs are attached to 2-phenylbenzimidazole-5-sulfonic acid (PBSA), an eminent UV-B filter widely used in many commercial sunscreen products to avoid skin erythema and DNA mutagenic photolesions. The photoinduced Förster resonance energy transfer (FRET) is investigated from PBSA to CCS QDs as a function of Cu concentration in CCS QDs using the steady-state photoluminescence and time-resolved photoluminescence measurements. A 2-fold increase in the magnitude of non-radiative energy transfer rate (K T(r)) is observed as the molar concentration of Cu in CCS QDs increases from 2 to 10 mM. Our findings suggest that in PBSA-CCS QD dyads, the FRET occurrence from PBSA to QDs is dictated by the dynamic mode of photoluminescence (PL) quenching. The bimolecular PL quenching rate constants (k q) estimated by Stern-Volmer's plots for PBSA-CCS QD dyads are of the order of 1010 M-1 s-1, which signifies that in the PBSA-CCS QD dyad FRET system, the process of PL quenching is entirely diffusion-controlled.
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Affiliation(s)
- Muhammad Mubeen
- Department
of Chemistry, Quaid-I-Azam University, Islamabad 45320, Pakistan
| | | | - Tehreem Gul
- Department
of Chemistry, Quaid-I-Azam University, Islamabad 45320, Pakistan
| | - Maria Mukhtar
- Department
of Chemistry, Quaid-I-Azam University, Islamabad 45320, Pakistan
| | - Anwar Ul-Hamid
- Core
Research Facilities, King Fahd University
of Petroleum & Minerals, Dhahran 31261, Saudi Arabia
| | - Azhar Iqbal
- Department
of Chemistry, Quaid-I-Azam University, Islamabad 45320, Pakistan
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Liang Y, Simaiti A, Xu M, Lv S, Jiang H, He X, Fan Y, Zhu S, Du B, Yang W, Li X, Yu P. Antagonistic Skin Toxicity of Co-Exposure to Physical Sunscreen Ingredients Zinc Oxide and Titanium Dioxide Nanoparticles. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:2769. [PMID: 36014634 PMCID: PMC9414962 DOI: 10.3390/nano12162769] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/04/2022] [Accepted: 08/09/2022] [Indexed: 06/15/2023]
Abstract
Being the main components of physical sunscreens, zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO2 NPs) are often used together in different brands of sunscreen products with different proportions. With the broad use of cosmetics containing these nanoparticles (NPs), concerns regarding their joint skin toxicity are becoming more and more prominent. In this study, the co-exposure of these two NPs in human-derived keratinocytes (HaCaT) and the in vitro reconstructed human epidermis (RHE) model EpiSkin was performed to verify their joint skin effect. The results showed that ZnO NPs significantly inhibited cell proliferation and caused deoxyribonucleic acid (DNA) damage in a dose-dependent manner to HaCaT cells, which could be rescued with co-exposure to TiO2 NPs. Further mechanism studies revealed that TiO2 NPs restricted the cellular uptake of both aggregated ZnO NPs and non-aggregated ZnO NPs and meanwhile decreased the dissociation of Zn2+ from ZnO NPs. The reduced intracellular Zn2+ ultimately made TiO2 NPs perform an antagonistic effect on the cytotoxicity caused by ZnO NPs. Furthermore, these joint skin effects induced by NP mixtures were validated on the epidermal model EpiSkin. Taken together, the results of the current research contribute new insights for understanding the dermal toxicity produced by co-exposure of different NPs and provide a valuable reference for the development of formulas for the secure application of ZnO NPs and TiO2 NPs in sunscreen products.
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Affiliation(s)
- Yan Liang
- Department of Toxicology, and Department of Medical Oncology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Aili Simaiti
- Department of Toxicology, and Department of Medical Oncology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Mingxuan Xu
- Department of Toxicology, and Department of Medical Oncology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Shenchong Lv
- Department of Toxicology, and Department of Medical Oncology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Hui Jiang
- Department of Toxicology, and Department of Medical Oncology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Xiaoxiang He
- Lishui International Travel Health-Care Center, Lishui 323000, China
| | - Yang Fan
- Department of Toxicology, and Department of Medical Oncology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Shaoxiong Zhu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science & Engineering, Zhejiang University, Hangzhou 310027, China
| | - Binyang Du
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science & Engineering, Zhejiang University, Hangzhou 310027, China
| | - Wei Yang
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Xiaolin Li
- Technical Center of Animal, Plant and Food Inspection and Quarantine of Shanghai Customs, Shanghai 200135, China
| | - Peilin Yu
- Department of Toxicology, and Department of Medical Oncology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
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Chang XP, Yu L, Zhang TS, Cui G. Quantum mechanics/molecular mechanics studies on the mechanistic photophysics of sunscreen oxybenzone in methanol solution. Phys Chem Chem Phys 2022; 24:13293-13304. [PMID: 35607908 DOI: 10.1039/d2cp01263d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we have employed the QM(CASPT2//CASSCF)/MM method to explore the photophysical and photochemical mechanism of oxybenzone (OB) in methanol solution. Based on the optimized minima, conical intersections and crossing points, and minimum-energy reaction paths related to excited-state intramolecular proton transfer (ESIPT) and excited-state decay paths in the 1ππ*, 1nπ*, 3ππ*, 3nπ*, and S0 states, we have identified several feasible excited-state relaxation pathways for the initially populated S2(1ππ*) state to decay to the initial enol isomer' S0 state. The major one is the singlet-mediated and stretch-torsion coupled ESIPT pathway, in which the system first undergoes an essentially barrierless 1ππ* ESIPT process to generate the 1ππ* keto species, and finally realizes its ground state recovery through the subsequent carbonyl stretch-torsion facilitating S1 → S0 internal conversion (IC) and the reverse ground-state intramolecular proton transfer (GSIPT) process. The minor ones are related to intersystem crossing (ISC) processes. At the S2(1ππ*) minimum, an S2(1ππ*)/S1(1nπ*)/T2(3nπ*) three-state intersection region helps the S2 system branch into the T1 state through a S2 → S1 → T1 or S2 → T2 → T1 process. Once it has reached the T1 state, the system may relax to the S0 state via direct ISC or via subsequent nearly barrierless 3ππ* ESIPT to yield the T1 keto tautomer and ISC. The resultant S0 keto species significantly undergoes reverse GSIPT and only a small fraction yields the trans-keto form that relaxes back more slowly. However, due to small spin-orbit couplings at T1/S0 crossing points, the ISC to S0 state occurs very slowly. The present work rationalizes not only the ultrafast excited-state decay dynamics of OB but also its phosphorescence emission at low temperature.
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Affiliation(s)
- Xue-Ping Chang
- College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang 464000, China.
| | - Li Yu
- College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang 464000, China.
| | - Teng-Shuo Zhang
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
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Mubeen M, Khalid MA, Mukhtar M, Sumreen P, Gul T, Ul Ain N, Shahrum S, Tabassum M, Ul-Hamid A, Iqbal A. Elucidating the Size-dependent FRET Efficiency in Interfacially Engineered Quantum Dots attached PBSA Sunscreen. Photochem Photobiol 2022; 98:1017-1024. [PMID: 35092012 DOI: 10.1111/php.13599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 01/24/2022] [Indexed: 11/30/2022]
Abstract
Applying sunscreen on human skin provides photoprotection against the harmful ultraviolet (UV) radiation of the sun. Sunscreen absorbs UV radiations and dissipates the absorbed energy through various radiative and non-radiative pathways. The attachment of functionalized quantum dots (QDs) to the sunscreen component is a novel idea to enhance the absorption cross-section of UV radiations. Therefore, the attachment of the sunscreen component to the ligand functionalized biocompatible QDs and the absorbed energy transfer from sunscreen to the QDs could work as a model system to overall improve the efficiency of the sunscreen. This study elucidates the mechanism of size-dependent Förster resonance energy transfer (FRET) efficiency and its rate between 2-phenylbenzimidazole-5-sulfonic acid (PBSA) and mercaptoacetic acid (MAA) functionalized CdS QDs. In the PBSA-QDs dyad, the PBSA (donor) dissipates UV-absorbed energy to the CdS QDs (acceptor). Following excitation at 306 nm, the steady-state photoluminescence (SSPL) and time-resolved photoluminescence (TRPL) techniques measurements demonstrate that both the non-radiative energy transfer efficiency and rate are QDs size-dependent in addition to donor-acceptor distance, and suggest that bigger sized-QDs result in an increase of the FRET efficiency.
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Affiliation(s)
- Muhammad Mubeen
- Department of Chemistry, Quaid-I-Azam University Islamabad-45320, Pakistan
| | | | - Maria Mukhtar
- Department of Chemistry, Quaid-I-Azam University Islamabad-45320, Pakistan
| | - Poshmal Sumreen
- Department of Chemistry, Quaid-I-Azam University Islamabad-45320, Pakistan
| | - Tehreem Gul
- Department of Chemistry, Quaid-I-Azam University Islamabad-45320, Pakistan
| | - Noor Ul Ain
- Department of Chemistry, Quaid-I-Azam University Islamabad-45320, Pakistan
| | - Saba Shahrum
- Department of Chemistry, Quaid-I-Azam University Islamabad-45320, Pakistan
| | - Mamoona Tabassum
- Department of Chemistry, Quaid-I-Azam University Islamabad-45320, Pakistan
| | - Anwar Ul-Hamid
- Core Research Facilities, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia
| | - Azhar Iqbal
- Department of Chemistry, Quaid-I-Azam University Islamabad-45320, Pakistan
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Chang XP, Zhang TS, Cui G. Theoretical Studies on the Excited-State Decay Mechanism of Homomenthyl Salicylate in a Gas Phase and an Acetonitrile Solution. J Phys Chem A 2021; 126:16-28. [PMID: 34963284 DOI: 10.1021/acs.jpca.1c07108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Here, we employ the CASPT2//CASSCF and QM(CASPT2//CASSCF)/MM approaches to explore the photochemical mechanism of homomenthyl salicylate (HMS) in vacuum and an acetonitrile solution. The results show that in both cases, the excited-state relaxation mainly involves a spectroscopically "bright" S1(1ππ*) state and the lower-lying T1 and T2 states. In the major relaxation pathway, the photoexcited S1 keto system first undergoes an essentially barrierless excited-state intramolecular proton transfer (ESIPT) to generate the S1 enol minimum, near which a favorable S1/S0 conical intersection decays the system to the S0 state followed by a reverse ground-state intramolecular proton transfer (GSIPT) to repopulate the initial S0 keto species. In the minor one, an S1/T2/T1 three-state intersection in the keto region makes the T1 state populated via direct and T2-mediated intersystem crossing (ISC) processes. In the T1 state, an ESIPT occurs, which is followed by ISC near a T1/S0 crossing point in the enol region to the S0 state and finally back to the S0 keto species. In addition, a T1/S0 crossing point near the T1 keto minimum can also help the system decay to the S0 keto species. However, small spin-orbit couplings between T1 and S0 at these T1/S0 crossing points make ISC to the S0 state very slow and make the system trapped in the T1 state for a while. The present work rationalizes not only the ultrafast excited-state decay dynamics of HMS but also its low quantum yield of phosphorescence at 77 K.
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Affiliation(s)
- Xue-Ping Chang
- College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang 464000, P. R. China
| | - Teng-Shuo Zhang
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, 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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Abiola TT, Auckloo N, Woolley JM, Corre C, Poigny S, Stavros VG. Unravelling the Photoprotection Properties of Garden Cress Sprout Extract. Molecules 2021; 26:molecules26247631. [PMID: 34946713 PMCID: PMC8705737 DOI: 10.3390/molecules26247631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/07/2021] [Accepted: 12/12/2021] [Indexed: 12/03/2022] Open
Abstract
Plants, as with humans, require photoprotection against the potentially damaging effects of overexposure to ultraviolet (UV) radiation. Previously, sinapoyl malate (SM) was identified as the photoprotective agent in thale cress. Here, we seek to identify the photoprotective agent in a similar plant, garden cress, which is currently used in the skincare product Detoxophane nc. To achieve this, we explore the photodynamics of both the garden cress sprout extract and Detoxophane nc with femtosecond transient electronic absorption spectroscopy. With the assistance of liquid chromatography-mass spectrometry, we determine that the main UV-absorbing compound in garden cress sprout extract is SM. Importantly, our studies reveal that the photoprotection properties of the SM in the garden cress sprout extract present in Detoxophane nc are not compromised by the formulation environment. The result suggests that Detoxophane nc containing the garden cress sprout extract may offer additional photoprotection to the end user in the form of a UV filter booster.
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Affiliation(s)
- Temitope T. Abiola
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK; (T.T.A.); (N.A.); (J.M.W.); (C.C.)
| | - Nazia Auckloo
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK; (T.T.A.); (N.A.); (J.M.W.); (C.C.)
- Warwick Integrative Synthetic Biology Centre and School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Jack M. Woolley
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK; (T.T.A.); (N.A.); (J.M.W.); (C.C.)
| | - Christophe Corre
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK; (T.T.A.); (N.A.); (J.M.W.); (C.C.)
- Warwick Integrative Synthetic Biology Centre and School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Stéphane Poigny
- Mibelle Group Biochemistry, Mibelle AG, Bolimattstrasse 1, CH-5033 Buchs, Switzerland;
| | - Vasilios G. Stavros
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK; (T.T.A.); (N.A.); (J.M.W.); (C.C.)
- Correspondence:
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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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10
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Rodrigues NDN, Woolley JM, Krokidi KM, Tesa-Serrate MA, Turner MAP, Hine NDM, Stavros VG. Effects of substituent position on aminobenzoate relaxation pathways in solution. Phys Chem Chem Phys 2021; 23:23242-23255. [PMID: 34632473 DOI: 10.1039/d1cp03759e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The negative effects of ultraviolet radiation (UVR) on human skin have led to the widespread use of sunscreens, i.e. skincare products containing UV filters to absorb, reflect or otherwise block UVR. The mechanisms by which UV filters dissipate energy following photoexcitation, i.e. their photodynamics, can crucially determine a molecule's performance as a sunscreen UV filter. In this work, we evaluate the effects of substituent position on the in-solution relaxation pathways of two derivates of methyl anthranilate (an ortho compound that is a precursor to the UV filter meradimate), meta- and para-methyl anthranilate, m-MA and p-MA, respectively. The photodynamics of m-MA were found to be sensitive to solvent polarity: its emission spectra show larger Stokes shifts with increasing polarity, and both the fluorescence quantum yield and lifetimes for m-MA increase in polar solvents. While the Stokes shifts for p-MA are much milder and more independent of solvent environment than those of m-MA, we find its fluorescence quantum yields to be sensitive not only to solvent polarity but to the hydrogen bonding character of the solvent. In both cases (m- and p-MA) we have found common computational methods to be insufficient to appropriately model the observed spectroscopic data, likely due to an inability to account for explicit solvent interactions, a known challenge in computational chemistry. Therefore, apart from providing insight into the photodynamics of anthranilate derivatives, the work presented here also provides a case study that may be of use to theoretical chemists looking to improve and develop explicit solvent computational methods.
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Affiliation(s)
- Natércia D N Rodrigues
- University of Warwick, Department of Chemistry, Coventry, CV4 7AL, UK. .,Lipotec SAU, Calle Isaac Peral, 17 Pol. Ind. Camí Ral, 08850 Barcelona, Spain
| | - Jack M Woolley
- University of Warwick, Department of Chemistry, Coventry, CV4 7AL, UK.
| | | | | | - Matthew A P Turner
- University of Warwick, Department of Chemistry, Coventry, CV4 7AL, UK. .,University of Warwick, Department of Physics, Coventry, CV4 7AL, UK
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Valverde D, de Araújo AVS, Borin AC. Photophysical Deactivation Mechanisms of the Pyrimidine Analogue 1-Cyclohexyluracil. Molecules 2021; 26:5191. [PMID: 34500625 PMCID: PMC8434193 DOI: 10.3390/molecules26175191] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/21/2021] [Accepted: 08/23/2021] [Indexed: 11/17/2022] Open
Abstract
The photophysical relaxation mechanisms of 1-cyclohexyluracil, in vacuum and water, were investigated by employing the Multi-State CASPT2 (MS-CASPT2, Multi-State Complete Active-Space Second-Order Perturbation Theory) quantum chemical method and Dunning's cc-pVDZ basis sets. In both environments, our results suggest that the primary photophysical event is the population of the S11(ππ*) bright state. Afterwards, two likely deactivation pathways can take place, which is sustained by linear interpolation in internal coordinates defined via Z-Matrix scans connecting the most important characteristic points. The first one (Route 1) is the same relaxation mechanism observed for uracil, its canonical analogue, i.e., internal conversion to the ground state through an ethylenic-like conical intersection. The other route (Route 2) is the direct population transfer from the S11(ππ*) bright state to the T23(nπ*) triplet state via an intersystem crossing process involving the (S11(ππ*)/T23(nπ*))STCP singlet-triplet crossing point. As the spin-orbit coupling is not too large in either environment, we propose that most of the electronic population initially on the S11(ππ*) state returns to the ground following the same ultrafast deactivation mechanism observed in uracil (Route 1), while a smaller percentage goes to the triplet manifold. The presence of a minimum on the S11(ππ*) potential energy hypersurface in water can help to understand why experimentally it is noticed suppression of the triplet states population in polar protic solvent.
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Affiliation(s)
- Danillo Valverde
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes, 748, São Paulo 05508-000, SP, Brazil;
| | | | - Antonio Carlos Borin
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes, 748, São Paulo 05508-000, SP, Brazil;
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12
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Toldo JM, do Casal MT, Barbatti M. Mechanistic Aspects of the Photophysics of UVA Filters Based on Meldrum Derivatives. J Phys Chem A 2021; 125:5499-5508. [PMID: 34151555 DOI: 10.1021/acs.jpca.1c03315] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Skin photoprotection against UVA radiation is crucial, but it is hindered by the sparsity of approved commercial UVA filters. Sinapoyl malate (SM) derivatives are promising candidates for a new class of UVA filters. They have been previously identified as an efficient photoprotective sunscreen in plants due to their fast nonradiative energy dissipation. Combining experimental and computational results, in our previous letter (J. Phys. Chem. Lett. 2021, 12, 337-344) we showed that coumaryl Meldrum (CMe) and sinapoyl Meldrum (SMe) are outstanding candidates for UVA filters in sunscreen formulations. Here, we deliver a comprehensive computational characterization of the excited-state dynamics of these molecules. Using reaction pathways and excited-state dynamics simulations, we could elucidate the photodeactivation mechanism of these molecules. Upon photoexcitation, they follow a two-step logistic decay. First, an ultrafast and efficient relaxation stabilizes the excited state alongside a 90° twisting around the allylic double bond, giving rise to a minimum with a twisted intramolecular excited-state (TICT) character. From this minimum, internal conversion to the ground state occurs after overcoming a 0.2 eV barrier. Minor differences in the nonradiative decay and fluorescence of CMe and SMe are associated with an additional minimum present only in the latter.
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Affiliation(s)
- Josene M Toldo
- Aix Marseille Université, CNRS, ICR, Av. Esc. Normandie-Niemen BJ5-D22, Marseille 13397, France
| | - Mariana T do Casal
- Aix Marseille Université, CNRS, ICR, Av. Esc. Normandie-Niemen BJ5-D22, Marseille 13397, France
| | - Mario Barbatti
- Aix Marseille Université, CNRS, ICR, Av. Esc. Normandie-Niemen BJ5-D22, Marseille 13397, France
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13
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Chang XP, Zhang TS, Fang YG, Cui G. Quantum Mechanics/Molecular Mechanics Studies on the Photophysical Mechanism of Methyl Salicylate. J Phys Chem A 2021; 125:1880-1891. [PMID: 33645980 DOI: 10.1021/acs.jpca.0c10589] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Methyl salicylate (MS) as a subunit of larger salicylates found in commercial sunscreens has been shown to exhibit keto-enol tautomerization and dual fluorescence emission via excited-state intramolecular proton transfer (ESIPT) after the absorption of ultraviolet (UV) radiation. However, its excited-state relaxation mechanism is unclear. Herein, we have employed the quantum mechanics(CASPT2//CASSCF)/molecular mechanics method to explore the ESIPT and excited-state relaxation mechanism of MS in the lowest three electronic states, that is, S0, S1, and T1 states, in a methanol solution. Based on the optimized geometric and electronic structures, conical intersections and crossing points, and minimum-energy paths combined with the computed linearly interpolated Cartesian coordinate paths, the photophysical mechanism of MS has been proposed. The S1 state is a spectroscopically bright 1ππ* state in the Franck-Condon region. From the initially populated S1 state, there exist three nonradiative relaxation paths to repopulate the S0 state. In the first one, the S1 system (i.e., ketoB form) first undergoes an ESIPT path to generate an S1 tautomer (i.e., enol form) that exhibits a large Stokes shift in experiments. The generated S1 enol tautomer further evolves toward the nearby S1/S0 conical intersection and then hops to the S0 state, followed by the backward ground-state intramolecular proton transfer (GSIPT) to the initial ketoB form S0 state. In the second one, the S1 system first hops through the S1 → T1 intersystem crossing (ISC) to the T1 state, which then further decays to the S0 state via T1 → S0 ISC at the T1/S0 crossing point. In the third path, the T1 system that stems from the S1 → T1 ISC process via the S1/T1 crossing point first takes place a T1 ESIPT to generate a T1 enol tautomer, which can further decay to the S0 state via T1-to-S0 ISC. Finally, the GSIPT occurs to back the system to the initial ketoB form S0 state. Our present work could contribute to understanding the photophysics of MS and its derivatives.
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Affiliation(s)
- Xue-Ping Chang
- College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang 464000, P. R. China
| | - Teng-Shuo Zhang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Ye-Guang Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, 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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14
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Abiola TT, Rodrigues NDN, Ho C, Coxon DJL, Horbury MD, Toldo JM, do Casal MT, Rioux B, Peyrot C, Mention MM, Balaguer P, Barbatti M, Allais F, Stavros VG. New Generation UV-A Filters: Understanding Their Photodynamics on a Human Skin Mimic. J Phys Chem Lett 2021; 12:337-344. [PMID: 33353308 DOI: 10.1021/acs.jpclett.0c03004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
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 (S1), these Meldrum-based phenolics undergo fast and efficient nonradiative decay to repopulate the electronic ground state (S0). We propose an initial ultrafast twisted intramolecular charge-transfer mechanism as these systems evolve out of the Franck-Condon region toward an S1/S0 conical intersection, followed by internal conversion to S0 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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Affiliation(s)
| | | | | | - Daniel J L Coxon
- EPSRC Centre for Doctoral Training in Diamond Science and Technology, Coventry, United Kingdom
| | - Michael D Horbury
- School of Electrical and Electronic Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | | | | | - Benjamin Rioux
- URD Agro-Biotechnologies (ABI), CEBB, AgroParisTech, 51110 Pomacle, France
| | - Cédric Peyrot
- URD Agro-Biotechnologies (ABI), CEBB, AgroParisTech, 51110 Pomacle, France
| | - Matthieu M Mention
- URD Agro-Biotechnologies (ABI), CEBB, AgroParisTech, 51110 Pomacle, France
| | | | | | - Florent Allais
- URD Agro-Biotechnologies (ABI), CEBB, AgroParisTech, 51110 Pomacle, France
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15
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Cao CN, Liu CF, Zhao L, Rao GW. New insight into the photoinduced wavelength dependent decay mechanisms of the ferulic acid system on the excited states. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 240:118565. [PMID: 32554260 DOI: 10.1016/j.saa.2020.118565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/28/2020] [Accepted: 05/29/2020] [Indexed: 06/11/2023]
Abstract
The ferulic acid (FA) is a kind of phenolic acid widely exists in nature plants. Apart from its medicinal values, the FA is also widely applied in cosmetic industry. Recently, it was found to have potential applications in commercial sunscreens for its strong photostability and photoprotection property from harmful UV rays. Such excellent property lies in the ultrafast decay process of the FA system when exposure to the UV light, but the underlying detailed relaxation pathway is still less clear-cut. In the current work, high-level ab initio electronic structure calculations and on-the-fly surface hopping dynamics simulations were employed to explore the photoinduced decay mechanism of the FA system both on the S1 and S3 states in the gas phase. The results provide a reasonable explanation for the wavelength dependent decay patterns of FA system. The S1 state decay pathway is driven by a re-emission process to dissipate excess energy. While for the S3 state deactivation process, the pathway is dominated by a non-adiabatic process driven by the internal conversion process through the conical intersection regions. A S3-S1-S0 two step decay pattern is proposed, and the pathways are mainly driven by a puckering distortion motion of the aromatic ring and a twisting motion around the bridging double bond. The calculation results contribute to a better understanding of detailed dynamics behavior of the FA deactivation process, and provide theoretical guidance for further design of efficient and environmentally friendly sunscreens.
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Affiliation(s)
- Cong-Neng Cao
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, PR China; Institute of Drug Development & Chemical Biology, Zhejiang University of Technology, Hangzhou 310014, PR China
| | - Cheng-Fu Liu
- School of Pharmaceutical Sciences, Gannan Medical University, Ganzhou 341000, PR China
| | - Li Zhao
- School of Science, China University of Petroleum (East China), Qingdao 266580, Shandong, PR China
| | - Guo-Wu Rao
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014, PR China; Institute of Drug Development & Chemical Biology, Zhejiang University of Technology, Hangzhou 310014, PR China.
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16
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Krokidi KM, Turner MAP, Pearcy PAJ, Stavros VG. A systematic approach to methyl cinnamate photodynamics. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1811910] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
| | - Matthew A. P. Turner
- Department of Chemistry, University of Warwick, Coventry, UK
- Department of Physics, University of Warwick, Coventry, UK
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17
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Abiola TT, Whittock AL, Stavros VG. Unravelling the Photoprotective Mechanisms of Nature-Inspired Ultraviolet Filters Using Ultrafast Spectroscopy. Molecules 2020; 25:E3945. [PMID: 32872380 PMCID: PMC7504748 DOI: 10.3390/molecules25173945] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/26/2020] [Accepted: 08/27/2020] [Indexed: 02/07/2023] Open
Abstract
There are several drawbacks with the current commercially available ultraviolet (UV) filters used in sunscreen formulations, namely deleterious human and ecotoxic effects. As a result of the drawbacks, a current research interest is in identifying and designing new UV filters. One approach that has been explored in recent years is to use nature as inspiration, which is the focus of this review. Both plants and microorganisms have adapted to synthesize their own photoprotective molecules to guard their DNA from potentially harmful UV radiation. The relaxation mechanism of a molecule after it has been photoexcited can be unravelled by several techniques, the ones of most interest for this review being ultrafast spectroscopy and computational methods. Within the literature, both techniques have been implemented on plant-, and microbial-inspired UV filters to better understand their photoprotective roles in nature. This review aims to explore these findings for both families of nature-inspired UV filters in the hope of guiding the future design of sunscreens.
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Affiliation(s)
- Temitope T. Abiola
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK; (T.T.A.); (A.L.W.)
| | - Abigail L. Whittock
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK; (T.T.A.); (A.L.W.)
- AS CDT, Senate House, University of Warwick, Coventry CV4 7AL, UK
| | - Vasilios G. Stavros
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK; (T.T.A.); (A.L.W.)
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18
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Blodgett KN, Fischer JL, Zwier TS, Sibert EL. The missing NH stretch fundamental in S 1 methyl anthranilate: IR-UV double resonance experiments and local mode theory. Phys Chem Chem Phys 2020; 22:14077-14087. [PMID: 32568351 DOI: 10.1039/d0cp01916j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The infrared spectra of jet-cooled methyl anthranilate (MA) and the MA-H2O complex are reported in both S0 and S1 states, recorded using fluorescence-dip infrared (FDIR) spectroscopy under jet-cooled conditions. Using a combination of local mode CH stretch modeling and scaled harmonic vibrational character, a near-complete assignment of the infrared spectra is possible over the 1400-3700 cm-1 region. While the NH stretch fundamentals are easily observed in the S0 spectrum, in the S1 state, the hydrogen bonded NH stretch shift is not readily apparent. Scaled harmonic calculations predict this fundamental at just below 2900 cm-1 with an intensity around 400 km mol-1. However, the experimental spectrum shows no evidence of this transition. A local mode theory is developed in which the NH stretch vibration is treated adiabatically. Minimizing the energy of the corresponding stretch state with one quantum of excitation leads to a dislocation of the H atom where there is equal sharing between N and O atoms. The sharing occurs as a result of significant molecular arrangement due to strong coupling of this NH stretch to other internal degrees of freedom and in particular to the contiguous HNC bend. A two-dimensional model of the coupling between the NH stretch and this bend highlights important nonlinear effects that are not captured by low order vibrational perturbation theory. In particular, the model predicts a dramatic dilution of the NH stretch oscillator strength over many transitions spread over more than 1000 cm-1, making it difficult to observe experimentally.
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Affiliation(s)
- Karl N Blodgett
- Department of Chemistry, Purdue University, West Lafayette, IN 47907-2084, USA.
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19
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Abstract
The skin is constantly exposed to various environmental stresses, in particular to the damage caused by pollution and ultraviolet radiation (UV), and as a consequence, the horny extract can be negatively impacted by the harmful influence of some of its surface components. The mechanisms involved in the degradation processes promoted by UV radiation are driven by the direct absorption of radiation via cellular chromophores, the formation of excited states and the consequent chemical reactions, or even by the photosensitization mechanisms, in which UV light is absorbed by the sensitizers that are excited and their reactions promote the formation of reactive oxygen species (ROS). The mechanisms of polluting agents are not yet fully understood, however, they indicate that one of the main mechanisms involved is oxidative stress by lipid peroxidation, with the ability to promote damage to the composition of sebum, the quality of the stratum corneum and also, promote aging skin. Recent studies demonstrate the potential of antioxidant agents, with an emphasis on products of natural origin, which try to promote the maintenance of the physiological balance of the skin.
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20
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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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21
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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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22
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Bacardit A, Cartoixà X. Revisiting the Role of Irradiance in the Determination of Sunscreens' Sun Protection Factor. J Phys Chem Lett 2020; 11:1209-1214. [PMID: 32075378 DOI: 10.1021/acs.jpclett.9b03437] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The efficacy of a sunscreen tends to be associated with its sun protection factor (SPF) value, a figure determined in a test that relies on the independence of the SPF value to both UV radiation dose and irradiance. We probe these assumptions when photoinduced product degradation is present, and we estimate that the theoretical limit for their validity is when the sunfilter active molecule relaxation time is faster than ∼10 ns. While such threshold relaxation time should be compatible with the expected ultrafast relaxation mechanisms of sunfilter molecules (picoseconds), recent research on sunfilter photodynamics has identified the existence of much longer-lived molecular states. Such long lifetimes could compromise sunscreen performance and make the SPF value very different in natural sun irradiance conditions than in the solar simulated conditions typically used in SPF determination tests.
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Affiliation(s)
| | - Xavier Cartoixà
- Departament d'Enginyeria Electrònica , Universitat Autònoma de Barcelona , 08193 Cerdanyola del Vallès , Spain
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23
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Holt EL, Krokidi KM, Turner MAP, Mishra P, Zwier TS, Rodrigues NDN, Stavros VG. Insights into the photoprotection mechanism of the UV filter homosalate. Phys Chem Chem Phys 2020; 22:15509-15519. [DOI: 10.1039/d0cp02610g] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Homosalate has been found to exhibit favourable photophysics for inclusion in sunscreens, using a combination of spectroscopic and computational approaches.
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Affiliation(s)
- Emily L. Holt
- Department of Chemistry
- University of Warwick
- Coventry
- UK
- Molecular Analytical Science Centre for Doctoral Training
| | | | - Matthew A. P. Turner
- Department of Chemistry
- University of Warwick
- Coventry
- UK
- Molecular Analytical Science Centre for Doctoral Training
| | - Piyush Mishra
- Department of Chemistry
- Purdue University
- West Lafayette
- USA
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24
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Sharma A, Kumar A, Li C, Sharma RK, Swihart MT. Microencapsulated UV filter@ZIF-8 based sunscreens for broad spectrum UV protection. RSC Adv 2020; 10:34254-34260. [PMID: 35519040 PMCID: PMC9056713 DOI: 10.1039/d0ra05828a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/04/2020] [Indexed: 11/21/2022] Open
Abstract
Encapsulation of organic UV filters in ZIF-8 nanoparticles produces a safer, more stable, and more effective sunscreen.
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Affiliation(s)
- Anu Sharma
- Department of Chemistry
- University of Delhi
- India
- Department of Chemical and Biological Engineering
- University at Buffalo (SUNY)
| | - Abhishek Kumar
- Department of Chemical and Biological Engineering
- University at Buffalo (SUNY)
- USA
| | - Changning Li
- Department of Chemical and Biological Engineering
- University at Buffalo (SUNY)
- USA
| | | | - Mark T. Swihart
- Department of Chemical and Biological Engineering
- University at Buffalo (SUNY)
- USA
- RENEW Institute
- University at Buffalo (SUNY)
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25
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Chang XP, Fang YG, Cui G. QM/MM Studies on the Photophysical Mechanism of a Truncated Octocrylene Model. J Phys Chem A 2019; 123:8823-8831. [PMID: 31550143 DOI: 10.1021/acs.jpca.9b07280] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Methyl 2-cyano-3,3-diphenylacrylate (MCDPA) shares the same molecular skeleton with octocrylene (OCR) that is one of the most common molecules used in commercially available sunscreens. However, its excited-state relaxation mechanism is unclear. Herein, we have used the QM(CASPT2//CASSCF)/MM method to explore spectroscopic properties, geometric and electronic structures, relevant conical intersections and crossing points, and excited-state relaxation paths of MCDPA in methanol solution. We found that in the Franck-Condon (FC) region, the V(1ππ*) state is energetically lower than the V'(1ππ*) state only by 2.8 kcal/mol and is assigned to experimentally observed maximum absorption band. From these two initially populated singlet states, there exist three nonradiative relaxation paths to repopulate the S0 state. In the first one, when the V(1ππ*) state is populated in the FC region, the system diabatically evolves along the V(1ππ*) state into its minimum where the internal conversion to S0 occurs. In the second one, the V'(1ππ*) state is populated in the FC region and the system adiabatically overcomes a barrier of ca. 3.0 kcal/mol to approach the V(1ππ*) minimum eventually leading to a V(1ππ*)-to-S0 internal conversion. In the third one, the V'(1ππ*) state first hops via the intersystem crossing to the T2 state, which then decays through the internal conversion to the T1 state. The T1 state is finally converted to the S0 state via the T1/S0 crossing point. Our present work contributes to understanding the photophysics of OCR and its variants.
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Affiliation(s)
- Xue-Ping Chang
- College of Chemistry and Chemical Engineering , Xinyang Normal University , Xinyang 464000 , P. R. China
| | - Ye-Guang Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry , Beijing Normal University , Beijing 100875 , 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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26
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Holt EL, Stavros VG. Applications of ultrafast spectroscopy to sunscreen development, from first principles to complex mixtures. INT REV PHYS CHEM 2019. [DOI: 10.1080/0144235x.2019.1663062] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Emily L. Holt
- Molecular Analytical Science Centre for Doctoral Training, Senate House, University of Warwick, Coventry, UK
- Department of Chemistry, University of Warwick, Coventry, UK
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Blodgett KN, Sun D, Fischer JL, Sibert EL, Zwier TS. Vibronic spectroscopy of methyl anthranilate and its water complex: hydrogen atom dislocation in the excited state. Phys Chem Chem Phys 2019; 21:21355-21369. [PMID: 31531502 DOI: 10.1039/c9cp04556b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Laser-induced fluorescence (LIF) excitation, dispersed fluorescence (DFL), UV-UV-hole burning, and UV-depletion spectra have been collected on methyl anthranilate (MA, methyl 2-aminobenzoate) and its water-containing complex (MA-H2O), under jet-cooled conditions in the gas phase. As a close structural analog of a sunscreen agent, MA has a strong absorption due to the S0-S1 transition that begins in the UV-A region, with the electronic origin at 28 852 cm-1 (346.6 nm). Unlike most sunscreens that have fast non-radiative pathways back to the ground state, MA fluoresces efficiently, with an excited state lifetime of 27 ns. Relative to methyl benzoate, inter-system crossing to the triplet manifold is shut off in MA by the strong intramolecular NHO[double bond, length as m-dash]C H-bond, which shifts the 3nπ* state well above the 1ππ* S1 state. Single vibronic level DFL spectra are used to obtain a near-complete assignment of the vibronic structure in the excited state. Much of the vibrational structure in the excitation spectrum is Franck-Condon activity due to three in-plane vibrations that modulate the distance between the NH2 and CO2Me groups, ν33 (421 cm-1), ν34 (366 cm-1), and ν36 (179 cm-1). Based on the close correspondence between experiment and theory at the TD-DFT B3LYP-D3BJ/def2TZVP level of theory, the major structural changes associated with electronic excitation are evaluated, leading to the conclusion that the major motion is a reorientation and constriction of the 6-membered H-bonded ring closed by the intramolecular NHO[double bond, length as m-dash]C H-bond. This leads to a shortening of the NHO[double bond, length as m-dash]C H-bond distance from 1.926 Å to 1.723 Å, equivalent to about a 25% reduction in the HO distance compared to full H-atom transfer. As a result, the excited state process near the S1 origin is a hydrogen atom dislocation that is brought about primarily by heavy atom motion, since the shortened H-bond distance results from extensive heavy-atom motion, with only a 0.03 Å increase in the NH bond length relative to its ground state value.
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Affiliation(s)
- Karl N Blodgett
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA.
| | - Dewei Sun
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA.
| | - Joshua L Fischer
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA.
| | - Edwin L Sibert
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Timothy S Zwier
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA.
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28
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Kinoshita SN, Inokuchi Y, Onitsuka Y, Kohguchi H, Akai N, Shiraogawa T, Ehara M, Yamazaki K, Harabuchi Y, Maeda S, Ebata T. The direct observation of the doorway 1nπ* state of methylcinnamate and hydrogen-bonding effects on the photochemistry of cinnamate-based sunscreens. Phys Chem Chem Phys 2019; 21:19755-19763. [PMID: 31259349 DOI: 10.1039/c9cp02914a] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electronic states and photochemistry including nonradiative decay (NRD) and trans(E) → cis(Z) isomerization of methylcinnamate (MC) and its hydrogen-bonded complex with methanol have been investigated under jet-cooled conditions. S1(1nπ*) and S2(1ππ*) are directly observed in MC. This is the first direct observation of S1(1nπ*) in cinnamate derivatives. Surprisingly, the order of the energies between the nπ* and ππ* states is opposite to substituted cinnamates. TD-DFT and SAC-CI calculations support the observed result and show that the substitution to the benzene ring largely lowers the 1ππ* energy while the effect on 1nπ* is rather small. The S2(ππ*) state lifetime of MC is determined to be equal to or shorter than 10 ps, and the production of the transient T1 state is observed. The T1(ππ*) state is calculated to have a structure in which propenyl C[double bond, length as m-dash]C is twisted by 90°, suggesting the trans → cis isomerization proceeds via T1. The production of the cis isomer is confirmed by low-temperature matrix-isolated FTIR spectroscopy. The effect of H-bonding is examined for the MC-methanol complex. The S2 lifetime of MC-methanol is determined to be 180 ps, indicating that the H-bonding to the C[double bond, length as m-dash]O group largely prohibits the 1ππ* → 1nπ* internal conversion. This lifetime elongation in the methanol complex also describes well a higher fluorescence quantum yield of MC in methanol solution than in cyclohexane, while such a solvent dependence is not observed in para-substituted MC. Determination of the photochemical reaction pathways of MC and MC-methanol will help us to design photofunctional cinnamate derivatives.
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Affiliation(s)
- Shin-Nosuke Kinoshita
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.
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29
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Zhao X, Luo J, Liu Y, Pandey P, Yang S, Wei D, Han K. Substitution Dependent Ultrafast Ultraviolet Energy Dissipation Mechanisms of Plant Sunscreens. J Phys Chem Lett 2019; 10:5244-5249. [PMID: 31436992 DOI: 10.1021/acs.jpclett.9b02175] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
An ultraviolet energy dissipation mechanism plays a critical role in the photoprotection effect of sunscreens. In this work, we discovered substitution dependent UV energy dissipation mechanisms of model plant sunscreen methyl sinapate (MS). We found that the initially populated V(ππ*) states of MS and p-OMeMS relax to the ground state nonradiatively along an ultrafast trans-cis photoisomerization in tens of picoseconds. However, for p-HMS, an internal conversion from V(ππ*) to a relative dark V'(ππ*) state occurs in less than 1 ps, leading to a branching of the excited-state relaxations. The V (ππ*) state still relaxes nonradiatively as in the case of MS and p-OMeMS. In contrast, the V'(ππ*) state decays to the ground state mainly by emitting photons, exhibiting a lifetime as long as 5 ns. It is the first time to definitely distinguish the dynamics between V(ππ*) and V'(ππ*) states in the study of sinapates and cinnamates. These results indicate the anticipation of the V'(ππ*) state should be avoided when designing sunscreens.
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Affiliation(s)
- Xi Zhao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
- University of Chinese Academy of Sciences, Beijing 10049, China
| | - Jian Luo
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
| | - Yan Liu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
| | - Pramod Pandey
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
| | - Songqiu Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
| | - Donghui Wei
- College of Chemistry and Molecular Engineering, Zhengzhou University, 100 Science Avenue, Zhengzhou, People's Republic of China
| | - Keli Han
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
- Institute of Molecular Sciences and Engineering, Shandong University, Qingdao 266237, P. R. China
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30
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Balevičius V, Wei T, Di Tommaso D, Abramavicius D, Hauer J, Polívka T, Duffy CDP. The full dynamics of energy relaxation in large organic molecules: from photo-excitation to solvent heating. Chem Sci 2019; 10:4792-4804. [PMID: 31183032 PMCID: PMC6521204 DOI: 10.1039/c9sc00410f] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 03/29/2019] [Indexed: 01/04/2023] Open
Abstract
In some molecular systems, such as nucleobases, polyenes or sunscreens, substantial amounts of photo-excitation energy are dissipated on a sub-picosecond time scale. Where does this energy go or among which degrees of freedom it is being distributed at such early times?
In some molecular systems, such as nucleobases, polyenes or the active ingredients of sunscreens, substantial amounts of photo-excitation energy are dissipated on a sub-picosecond time scale, raising questions such as: where does this energy go or among which degrees of freedom it is being distributed at such early times? Here we use transient absorption spectroscopy to track excitation energy dispersing from the optically accessible vibronic subsystem into the remaining vibrational subsystem of the solute and solvent. Monitoring the flow of energy during vibrational redistribution enables quantification of local molecular heating. Subsequent heat dissipation away from the solute molecule is characterized by classical thermodynamics and molecular dynamics simulations. Hence, we present a holistic approach that tracks the internal temperature and vibronic distribution from the act of photo-excitation to the restoration of the global equilibrium. Within this framework internal vibrational redistribution and vibrational cooling are emergent phenomena. We demonstrate the validity of the framework by examining a highly controversial example, carotenoids. We show that correctly accounting for the local temperature unambiguously explains their energetically and temporally congested spectral dynamics without the ad hoc postulation of additional ‘dark’ states. An immediate further application of this approach would be to monitor the excitation and thermal dynamics of pigment–protein systems.
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Affiliation(s)
- Vytautas Balevičius
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
| | - Tiejun Wei
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
| | - Devis Di Tommaso
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
| | - Darius Abramavicius
- Institute of Chemical Physics , Vilnius University , Sauletekio av. 9 , Vilnius , LT-10222 , Lithuania
| | - Jürgen Hauer
- Fakultät für Chemie , Technical University of Munich , Lichtenbergstraße 4 , D-85748 Garching , Germany.,Photonics Institute , TU Wien , Gußhausstraße 27 , 1040 Vienna , Austria
| | - Tomas Polívka
- Institute of Physics and Biophysics , Faculty of Science , University of South Bohemia , Branišovská 1760 , 37005 České Budějovice , Czech Republic
| | - Christopher D P Duffy
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
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Tuttle WD, Gardner AM, Whalley LE, Kemp DJ, Wright TG. Effects of symmetry, methyl groups and serendipity on intramolecular vibrational energy dispersal. Phys Chem Chem Phys 2019; 21:14133-14152. [DOI: 10.1039/c8cp02757a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Intramolecular vibrational dispersal of vibrational energy is more efficient in the symmetrically-substituted p-xylene molecule than in p-fluorotoluene, p-chlorofluorobenzene or p-difluorobenzene.
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Affiliation(s)
- William D. Tuttle
- School of Chemistry, University of Nottingham, University Park
- Nottingham
- UK
| | - Adrian M. Gardner
- School of Chemistry, University of Nottingham, University Park
- Nottingham
- UK
| | - Laura E. Whalley
- School of Chemistry, University of Nottingham, University Park
- Nottingham
- UK
| | - David J. Kemp
- School of Chemistry, University of Nottingham, University Park
- Nottingham
- UK
| | - Timothy G. Wright
- School of Chemistry, University of Nottingham, University Park
- Nottingham
- UK
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32
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Wong NGK, Berenbeim JA, Hawkridge M, Matthews E, Dessent CEH. Mapping the intrinsic absorption properties and photodegradation pathways of the protonated and deprotonated forms of the sunscreen oxybenzone. Phys Chem Chem Phys 2019; 21:14311-14321. [PMID: 30680382 DOI: 10.1039/c8cp06794e] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sunscreens provide vital protection against the photodamaging effects of UV radiation, however, many fundamental questions remain about the detailed mechanisms by which they dissipate UV energy. One such issue is the extent to which the pH environment of an organic sunscreen molecule alters its effectiveness, both in terms of ability to absorb UV radiation, and also its potential to photodegrade. Here, we use gas-phase laser photodissociation spectroscopy for the first time to measure the intrinsic UVA-UVC absorption spectra and associated photodegradation products of protonated and deprotonated oxybenzone, away from the complications of bulk mixtures. Our results reveal that protonation state has a dramatic effect on the absorption and photodissociation properties of this sunscreen. While the UV absorption profile of oxybenzone is only modestly affected by protonation across the range from 400-216 nm, deprotonated oxybenzone displays a significantly modified absorption spectrum, with very low photoabsorption between 370-330 nm. Protonated oxybenzone primarily photofragments by rupture of the bonds on either side of the central carbonyl group, producing cationic fragments with m/z 151 and 105. Additional lower mass photofragments (e.g. m/z 95 and 77) are also observed. The production spectra for the photofragments from protonated oxybenzone fall into two distinct categories, which we discuss in the context of different excited state decay pathways. For deprotonated oxybenzone, the major photofragments observed are m/z 211 and 212, which are associated with the ejection of methane and the methyl free radical from the parent ion, respectively. Implications for the suitability of oxybenzone in its protonated and deprotonated forms as an optimum sunscreen molecule are discussed.
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Affiliation(s)
- Natalie G K Wong
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
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33
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Wavepacket insights into the photoprotection mechanism of the UV filter methyl anthranilate. Nat Commun 2018; 9:5188. [PMID: 30518753 PMCID: PMC6281654 DOI: 10.1038/s41467-018-07681-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 11/16/2018] [Indexed: 12/23/2022] Open
Abstract
Meradimate is a broad-spectrum ultraviolet absorber used as a chemical filter in commercial sunscreens. Herein, we explore the ultrafast photodynamics occurring in methyl anthranilate (precursor to Meradimate) immediately after photoexcitation with ultraviolet radiation to understand the mechanisms underpinning Meradimate photoprotection. Using time-resolved photoelectron spectroscopy, signal from the first singlet excited state of methyl anthranilate shows an oscillatory behavior, i.e., quantum beats. Our studies reveal a dependence of the observed beating frequencies on photoexcitation wavelength and photoelectron kinetic energy, unveiling the different Franck-Condon overlaps between the vibrational levels of the ground electronic, first electronic excited, and ground cationic states of methyl anthranilate. By evaluating the behavior of these beats with increasing photon energy, we find evidence for intramolecular vibrational energy redistribution on the first electronic excited state. Such energy redistribution hinders efficient relaxation of the electronic excited state, making methyl anthranilate a poor choice for an efficient, efficacious sunscreen chemical filter. Here, the authors explore the ultrafast photodynamics of methyl anthranilate. From the quantum beat behavior, the authors find evidence for ultrafast energy redistribution processes which hinder excited state relaxation, making methyl anthranilate a poor choice for a sunscreen chemical filter.
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34
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Rodrigues ND, Cole-Filipiak NC, Turner MA, Krokidi K, Thornton GL, Richings GW, Hine ND, Stavros VG. Substituent position effects on sunscreen photodynamics: A closer look at methyl anthranilate. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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35
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Kinoshita SN, Miyazaki Y, Sumida M, Onitsuka Y, Kohguchi H, Inokuchi Y, Akai N, Shiraogawa T, Ehara M, Yamazaki K, Harabuchi Y, Maeda S, Taketsugu T, Ebata T. Different photoisomerization routes found in the structural isomers of hydroxy methylcinnamate. Phys Chem Chem Phys 2018; 20:17583-17598. [PMID: 29693100 DOI: 10.1039/c8cp00414e] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
An experimental and theoretical study has been carried out to elucidate the nonradiative decay (NRD) and trans(E) → cis(Z) isomerization from the S1 (1ππ*) state of structural isomers of hydroxy methylcinnamate (HMC); ortho-, meta- and para-HMC (o-, m- and p-HMC). A low temperature matrix-isolation Fourier Transform Infrared (FTIR) spectroscopic study revealed that all the HMCs are cis-isomerized upon UV irradiation. A variety of laser spectroscopic methods have been utilized for jet-cooled gas phase molecules to investigate the vibronic structure and lifetimes of the S1 state, and to detect the transient state appearing in the NRD process. In p-HMC, the zero-point level of the S1 state decays as quickly as 9 ps. A transient electronic state reported by Tan et al. (Faraday Discuss. 2013, 163, 321-340) was reinvestigated by nanosecond UV-tunable deep UV pump-probe spectroscopy and was assigned to the T1 state. For m- and o-HMC, the lifetime at the zero-point energy level of S1 is 10 ns and 6 ns, respectively, but it becomes substantially shorter at an excess energy higher than 1000 cm-1 and 600 cm-1, respectively, indicating the onset of NRD. Different from p-HMC, no transient state (T1) was observed in m- nor o-HMC. These experimental results are interpreted with the aid of TDDFT calculations by considering the excited-state reaction pathways and the radiative/nonradiative rate constants. It is concluded that in p-HMC, the trans → cis isomerization proceeds via a [trans-S1 → 1nπ* → T1 → cis-S0] scheme. On the other hand, in o- and m-HMC, the isomerization proceeds via a [trans-S1 → twisting along the C[double bond, length as m-dash]C double bond by 90° on S1 → cis-S0] scheme. The calculated barrier height along the twisting coordinate agrees well with the observed onset of the NRD channel for both o- and m-HMC.
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Affiliation(s)
- Shin-Nosuke Kinoshita
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.
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36
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Woolley JM, Staniforth M, Horbury MD, Richings GW, Wills M, Stavros VG. Unravelling the Photoprotection Properties of Mycosporine Amino Acid Motifs. J Phys Chem Lett 2018; 9:3043-3048. [PMID: 29751729 DOI: 10.1021/acs.jpclett.8b00921] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Photoprotection from harmful ultraviolet (UV) radiation exposure is a key problem in modern society. Mycosporine-like amino acids found in fungi, cyanobacteria, macroalgae, phytoplankton, and animals are already presenting a promising form of natural photoprotection in sunscreen formulations. Using time-resolved transient electronic absorption spectroscopy and guided by complementary ab initio calculations, we help to unravel how the core structures of these molecules perform under UV irradiation. Through such detailed insight into the relaxation mechanisms of these ubiquitous molecules, we hope to inspire new thinking in developing next-generation photoprotective molecules.
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Affiliation(s)
- Jack M Woolley
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , U.K
| | - Michael Staniforth
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , U.K
| | - Michael D Horbury
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , U.K
| | - Gareth W Richings
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , U.K
| | - Martin Wills
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , U.K
| | - Vasilios G Stavros
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , U.K
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37
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Baker LA, Staniforth M, Flourat AL, Allais F, Stavros VG. Gas-Solution Phase Transient Absorption Study of the Plant Sunscreen Derivative Methyl Sinapate. CHEMPHOTOCHEM 2018. [DOI: 10.1002/cptc.201800060] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Lewis A. Baker
- Department of Chemistry; University of Warwick; Gibbet Hill Road Coventry CV4 7AL United Kingdom
- Present address: Department of Science; George Abbot School; Woodruff Avenue Guildford, Surrey GU1 1XX United Kingdom
| | - Michael Staniforth
- Department of Chemistry; University of Warwick; Gibbet Hill Road Coventry CV4 7AL United Kingdom
| | - Amandine L. Flourat
- Chaire Agro-Biotechnologies Industrielles (ABI); AgroParisTech; CEBB 3 rue des Rouges Terres F-51110 Pomacle France
| | - Florent Allais
- Chaire Agro-Biotechnologies Industrielles (ABI); AgroParisTech; CEBB 3 rue des Rouges Terres F-51110 Pomacle France
| | - Vasilios G. Stavros
- Department of Chemistry; University of Warwick; Gibbet Hill Road Coventry CV4 7AL United Kingdom
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Abstract
Despite the pivotal role of ultraviolet (UV) radiation in sustaining life on Earth, overexposure to this type of radiation can have catastrophic effects, such as skin cancer. Sunscreens, the most common form of artificial protection against such harmful effects, absorb UV radiation before it reaches vulnerable skin cells. Absorption of UV radiation prompts ultrafast molecular events in sunscreen molecules which, ideally, would allow for fast and safe dissipation of the excess energy. However, our knowledge of these mechanisms remains limited. In this article, we will review recent advances in the field of ultrafast photodynamics (light induced molecular processes occurring within femtoseconds, fs, 10-15 s to picoseconds, ps, 10-12 s) of sunscreens. We follow a bottom-up approach to common sunscreen active ingredients, analysing any emerging trends from the current literature on the subject. Moreover, we will identify the main questions that remain unanswered, pinpoint some of the main challenges and finally comment on the outlook of this exciting field of research.
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39
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Rodrigues N, Cole-Filipiak N, Horbury M, Staniforth M, Karsili T, Peperstraete Y, Stavros V. Photophysics of the sunscreen ingredient menthyl anthranilate and its precursor methyl anthranilate: A bottom-up approach to photoprotection. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2017.11.042] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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40
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Gardner AM, Tuttle WD, Whalley LE, Wright TG. Direct observation of vibrational energy dispersal via methyl torsions. Chem Sci 2018; 9:2270-2283. [PMID: 29719700 PMCID: PMC5897844 DOI: 10.1039/c7sc05309f] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 01/24/2018] [Indexed: 01/01/2023] Open
Abstract
Explicit evidence for the role of methyl rotor levels in promoting energy dispersal is reported. A set of coupled zero-order vibration/vibration-torsion (vibtor) levels in the S1 state of para-fluorotoluene (pFT) are investigated. Two-dimensional laser-induced fluorescence (2D-LIF) and two-dimensional zero-kinetic-energy (2D-ZEKE) spectra are reported, and the assignment of the main features in both sets of spectra reveals that the methyl torsion is instrumental in providing a route for coupling between vibrational levels of different symmetry classes. We find that there is very localized, and selective, dissipation of energy via doorway states, and that, in addition to an increase in the density of states, a critical role of the methyl group is a relaxation of symmetry constraints compared to direct vibrational coupling.
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Affiliation(s)
- Adrian M Gardner
- School of Chemistry , University of Nottingham , University Park , Nottingham NG7 2RD , UK .
| | - William D Tuttle
- School of Chemistry , University of Nottingham , University Park , Nottingham NG7 2RD , UK .
| | - Laura E Whalley
- School of Chemistry , University of Nottingham , University Park , Nottingham NG7 2RD , UK .
| | - Timothy G Wright
- School of Chemistry , University of Nottingham , University Park , Nottingham NG7 2RD , UK .
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QUINA FRANKH, BASTOS ERICKL. Chemistry Inspired by the Colors of Fruits, Flowers and Wine. ACTA ACUST UNITED AC 2018; 90:681-695. [DOI: 10.1590/0001-3765201820170492] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 08/25/2017] [Indexed: 11/22/2022]
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