1
|
An S, Kim D, Kim J, Kim SK. Excited-state chemistry of the nitromethane anion mediated by the dipole-bound states revealed by photofragment action spectroscopy. Chem Sci 2023; 14:12231-12237. [PMID: 37969601 PMCID: PMC10631229 DOI: 10.1039/d3sc04342h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 10/12/2023] [Indexed: 11/17/2023] Open
Abstract
We report the first experimental observation of the excited dipole-bound state (DBS) of the cryogenically cooled nitromethane anion (CH3NO2-), where the excess electron is loosely attached to the singlet or triplet neutral-core. Photofragment and photodetachment action spectra have been employed for the dynamic exploration of Feshbach resonances located even far above the electron detachment threshold, giving excitation profiles from the ground anionic state (D0) to the DBSs which match quite well with the spectral structures of the photoelectron spectra. This indicates that the electron transfer from the nonvalence orbital (of DBS) to the valence orbital (of anion) is mainly responsible for the anionic fragmentation channels, giving strong evidence for that the DBS plays a dynamic doorway-role in the anionic fragmentation reactions. Photofragment action spectra have also been obtained for the anionic clusters of (CH3NO2)2-, (CH3NO2)3-, or (CH3NO2·H2O)-, giving the relative yields of various fragments as a function of the excitation energy for each cluster. The absorption profiles of the anionic clusters exhibit substantial blue-shifts compared to the bare nitromethane anion as their ground states are much stabilized by solvation. The anionic fragmentation pattern varies among different clusters, giving essential clues for the thorough understanding of the whole anionic dynamics such as the dynamic role of the short-lived nonvalence-bound states of the clusters.
Collapse
Affiliation(s)
- Sejun An
- Department of Chemistry, KAIST Daejeon 34141 Republic of Korea
| | - Dabin Kim
- Department of Chemistry, KAIST Daejeon 34141 Republic of Korea
| | - Junggil Kim
- Department of Chemistry, KAIST Daejeon 34141 Republic of Korea
| | - Sang Kyu Kim
- Department of Chemistry, KAIST Daejeon 34141 Republic of Korea
| |
Collapse
|
2
|
Wong NGK, Sereli M, Anstöter CS, Dessent CEH. Photochemical Degradation of the UV Filter Octyl Methoxy Cinnamate Probed via Laser-Interfaced Mass Spectrometry. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27248796. [PMID: 36557928 PMCID: PMC9780824 DOI: 10.3390/molecules27248796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/06/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022]
Abstract
Octyl methoxycinnamate (OMC) is a common UVA and UVB filter molecule that is widely used in commercial sunscreens. Here, we used gas-phase laser photodissociation spectroscopy to characterise the intrinsic photostability and photodegradation products of OMC by studying the system in its protonated form, i.e., [OMC·H]+. The major photofragments observed were m/z 179, 161, and 133, corresponding to fragmentation on either side of the ether oxygen of the ester group (m/z 179 and 161) or the C-C bond adjacent to the ester carbonyl group. Additional measurements were obtained using higher-energy collisional dissociation mass spectrometry (HCD-MS) to identify fragments that resulted from the breakdown of the vibrationally hot electronic ground state. We found that the m/z 179 and 161 ions were the main fragments produced by this route. Notably, the m/z 133 ion was not observed through HCD-MS, revealing that this product ion is only produced through a photochemical route. Our results demonstrate that UV photoexcitation of OMC is able to access a dissociative excited-state surface that uniquely leads to the rupture of the C-C bond adjacent to the key ester carbonyl group.
Collapse
|
3
|
Wong NGK, Rankine CD, Anstöter CS, Dessent CEH. Photostability of the deprotonated forms of the UV filters homosalate and octyl salicylate: molecular dissociation versus electron detachment following UV excitation. Phys Chem Chem Phys 2022; 24:17068-17076. [PMID: 35791920 PMCID: PMC9301628 DOI: 10.1039/d2cp01612e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
While common molecular anions show a strong propensity to undergo electron detachment upon UV excitation, this process often occurs in competition with molecular ion dissociation. The factors that affect the balance between these two major possible decay pathways have not been well understood to date. Laser photodissociation spectroscopy of the deprotonated forms of the UV filter molecules, Homosalate (HS) and Octyl Salicylate (OS), i.e. [HS - H]- and [OS - H]-, was used to acquire gas-phase UV absorption spectra for [HS - H]- and [OS - H]-via photodepletion from 3.0-5.8 eV. No photofragmentation (i.e. dissociation of the ionic molecular framework) was observed for either [HS - H]- and [OS - H]- following photoexcitation, revealing that electron loss entirely dominates the electronic decay pathways for these systems. High-level quantum chemical calculations were used to map out the excited states associated with [HS - H]- and [OS - H]-, revealing that the minimum-energy crossing points (MECPs) between the S1 and S0 states are located in elevated regions of the potential energy surface, making internal conversion unlikely. These results are consistent with our experimental observation that electron detachment out-competes hot ground state molecular fragmentation. More generally, our results reveal that the competition between molecular dissociation and electron detachment following anion photoexcitation can be determined by the magnitude of the energy gap between the excitation energy and the MECPs, rather than being a simple function of whether the excitation energy lies above the anion's vertical detachment energy.
Collapse
Affiliation(s)
- Natalie G K Wong
- Department of Chemistry, University of York, Heslington, YO10 5DD, UK.
| | - Conor D Rankine
- Chemistry - School of Natural and Environmental Sciences, Newcastle University, Newcastle, upon Tyne, UK
| | - Cate S Anstöter
- Department of Chemistry, University of York, Heslington, YO10 5DD, UK.
| | | |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Wong NGK, Dessent CEH. Illuminating the Effect of the Local Environment on the Performance of Organic Sunscreens: Insights From Laser Spectroscopy of Isolated Molecules and Complexes. Front Chem 2022; 9:812098. [PMID: 35096773 PMCID: PMC8789676 DOI: 10.3389/fchem.2021.812098] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 12/20/2021] [Indexed: 12/11/2022] Open
Abstract
Sunscreens are essential for protecting the skin from UV radiation, but significant questions remain about the fundamental molecular-level processes by which they operate. In this mini review, we provide an overview of recent advanced laser spectroscopic studies that have probed how the local, chemical environment of an organic sunscreen affects its performance. We highlight experiments where UV laser spectroscopy has been performed on isolated gas-phase sunscreen molecules and complexes. These experiments reveal how pH, alkali metal cation binding, and solvation perturb the geometric and hence electronic structures of sunscreen molecules, and hence their non-radiative decay pathways. A better understanding of how these interactions impact on the performance of individual sunscreens will inform the rational design of future sunscreens and their optimum formulations.
Collapse
Affiliation(s)
- Natalie G K Wong
- Department of Chemistry, University of York, York, United Kingdom
| | | |
Collapse
|
6
|
Marlton SJP, Trevitt A. Laser Photodissocation, Action Spectroscopy and Mass Spectrometry Unite to Detect and Separate Isomers. Chem Commun (Camb) 2022; 58:9451-9467. [DOI: 10.1039/d2cc02101c] [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
The separation and detection of isomers remains a challenge for many areas of mass spectrometry. This article highlights laser photodissociation and ion mobility strategies that have been deployed to tackle...
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
Wong NGK, Rhodes C, Dessent CEH. Photodegradation of Riboflavin under Alkaline Conditions: What Can Gas-Phase Photolysis Tell Us about What Happens in Solution? Molecules 2021; 26:6009. [PMID: 34641554 PMCID: PMC8512791 DOI: 10.3390/molecules26196009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/25/2021] [Accepted: 09/30/2021] [Indexed: 11/16/2022] Open
Abstract
The application of electrospray ionisation mass spectrometry (ESI-MS) as a direct method for detecting reactive intermediates is a technique of developing importance in the routine monitoring of solution-phase reaction pathways. Here, we utilise a novel on-line photolysis ESI-MS approach to detect the photoproducts of riboflavin in aqueous solution under mildly alkaline conditions. Riboflavin is a constituent of many food products, so its breakdown processes are of wide interest. Our on-line photolysis setup allows for solution-phase photolysis to occur within a syringe using UVA LEDs, immediately prior to being introduced into the mass spectrometer via ESI. Gas-phase photofragmentation studies via laser-interfaced mass spectrometry of deprotonated riboflavin, [RF - H]-, the dominant solution-phase species under the conditions of our study, are presented alongside the solution-phase photolysis. The results obtained illustrate the extent to which gas-phase photolysis methods can inform our understanding of the corresponding solution-phase photochemistry. We determine that the solution-phase photofragmentation observed for [RF - H]- closely mirrors the gas-phase photochemistry, with the dominant m/z 241 condensed-phase photoproduct also being observed in gas-phase photodissociation. Further gas-phase photoproducts are observed at m/z 255, 212, and 145. The value of exploring both the gas- and solution-phase photochemistry to characterise photochemical reactions is discussed.
Collapse
Affiliation(s)
| | | | - Caroline E. H. Dessent
- Department of Chemistry, University of York, Heslington YO10 5DD, UK; (N.G.K.W.); (C.R.)
| |
Collapse
|
9
|
Wong NK, Rankine CD, Dessent CEH. Measurement of the Population of Electrosprayed Deprotomers of Coumaric Acids Using UV-Vis Laser Photodissociation Spectroscopy. J Phys Chem A 2021; 125:6703-6714. [PMID: 34342453 PMCID: PMC8389988 DOI: 10.1021/acs.jpca.1c04880] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/08/2021] [Indexed: 01/05/2023]
Abstract
The measurement of deprotonation sites in multifunctional molecules following electrospray ionization is important to better inform a wide range of spectroscopic and photophysical studies that use electrospray to prepare molecular species for study in the gas phase. We demonstrate that low-resolution UV-vis laser photodissociation spectroscopy can be applied in situ to identify the deprotomers of three coumaric acids, trans-para-coumaric acid (CMA), trans-caffeic acid (CA), and trans-ferulic acid (FA), formed via electrospray. Electronic absorption spectra of the deprotonated coumaric acids are recorded via photodepletion and photofragmentation following electrospray from solutions of ethanol and acetonitrile. By comparing the experimental spectra to wave function theory calculations, we are able to confirm the presence of phenoxide and carboxylate deprotomers upon electrospray for all three coumaric acids, when sprayed from both protic and aprotic solvents. Ratios of the phenoxide:carboxylate deprotomers are obtained by generating summed theoretical absorption spectra that reproduce the experimental spectra. We find that choice of electrospray solvent has little effect on the ratio of deprotomers obtained for deprotonated CMA and CA but has a greater impact for FA. Our results are in excellent agreement with previous work conducted on deprotonated CMA using IR spectroscopy and demonstrate that UV photodissociation spectroscopy of electrosprayed ions has potential as a diagnostic tool for identifying deprotomeric species.
Collapse
Affiliation(s)
- Natalie
G. K. Wong
- Department
of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
| | - Conor D. Rankine
- School
of Natural and Environmental Sciences, Newcastle
University, Newcastle-upon-Tyne NE1 7RU, U.K.
| | | |
Collapse
|
10
|
Wong NK, Rankine CD, Dessent CEH. Linking Electronic Relaxation Dynamics and Ionic Photofragmentation Patterns for the Deprotonated UV Filter Benzophenone-4. J Phys Chem Lett 2021; 12:2831-2836. [PMID: 33719458 PMCID: PMC8041369 DOI: 10.1021/acs.jpclett.1c00423] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Understanding how deprotonation impacts the photophysics of UV filters is critical to better characterize how they behave in key alkaline environments including surface waters and coral reefs. Using anion photodissociation spectroscopy, we have measured the intrinsic absorption electronic spectroscopy (400-214 nm) and numerous accompanying ionic photofragmentation pathways of the benzophenone-4 anion ([BP4-H]-). Relative ion yield plots reveal the locations of the bright S1 and S3 excited states. For the first time for an ionic UV filter, ab initio potential energy surfaces are presented to provide new insight into how the photofragment identity maps the relaxation pathways. These calculations reveal that [BP4-H]- undergoes excited-state decay consistent with a statistical fragmentation process where the anion breaks down on the ground state after nonradiative relaxation. The broader relevance of the results in providing a basis for interpreting the relaxation dynamics of a wide range of gas-phase ionic systems is discussed.
Collapse
Affiliation(s)
- Natalie
G. K. Wong
- Department
of Chemistry, University of York, Heslington, York, YO10 5DD, U.K.
| | - Conor D. Rankine
- School
of Natural and Environmental Sciences, Newcastle
University, Newcastle-upon-Tyne, NE1 7RU, U.K.
| | | |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Xing J, Yuan D, Xie H, Wang N, Liu H, Yang L, Xu Y, Liu Z. Preparation of Efficient Ultraviolet-Protective Transparent Coating by Using a Titanium-Containing Hybrid Oligomer. ACS APPLIED MATERIALS & INTERFACES 2021; 13:5592-5601. [PMID: 33476118 DOI: 10.1021/acsami.0c20862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ultraviolet (UV) radiation is closely related to people's lives, but excess UV exposure has led to a series of problems. UV protection technology plays a vital role in our life. The most commonly adopted UV protection technology is to use UV-absorbing materials to make protective coatings, including sunscreen cream for human skin and sunscreen coating for materials. Conventional organic UV-protective coatings have low stability and are sensitive to heat, while inorganic UV-protective coating with highly efficient UV-protective performance usually need high processing temperatures and exhibit low transparency. Here, we report a Ti-PEG-Si cross-linked inorganic-organic hybrid material, which exhibits good UV-absorbing performance. By using these UV-absorbing materials, an efficient transparent UV-absorbing coating could be easily prepared at room temperature (298 K). The UV-absorbing coating is mainly composed of titanium and silicon connected by PEG200. PEG200 as a cross-linker can improve the UV-absorption performance of the coating and increase its visible light transmittance. At the same time, the existence of PEG200 can effectively increase the stability and elasticity of the coating and maintain its mechanical properties after UV irradiation. Furthermore, the coating could maintain highly UV-protective performance and could be transparent even after thermal treatment at high temperature (973 K). From this point of view, the hybrid materials have considerable application potential in next-generation UV protective coatings, especially with their utilization in heat-sensitive substrates or under high-temperature conditions.
Collapse
Affiliation(s)
- Jiacheng Xing
- National Engineering Laboratory for Methanol to Olefins, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Danhua Yuan
- National Engineering Laboratory for Methanol to Olefins, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Hua Xie
- National Engineering Laboratory for Methanol to Olefins, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Nan Wang
- National Engineering Laboratory for Methanol to Olefins, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hanbang Liu
- National Engineering Laboratory for Methanol to Olefins, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liping Yang
- National Engineering Laboratory for Methanol to Olefins, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunpeng Xu
- National Engineering Laboratory for Methanol to Olefins, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Zhongmin Liu
- National Engineering Laboratory for Methanol to Olefins, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
13
|
Kinoshita SN, Harabuchi Y, Inokuchi Y, Maeda S, Ehara M, Yamazaki K, Ebata T. Substitution effect on the nonradiative decay and trans → cis photoisomerization route: a guideline to develop efficient cinnamate-based sunscreens. Phys Chem Chem Phys 2021; 23:834-845. [PMID: 33284297 DOI: 10.1039/d0cp04402d] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Cinnamate derivatives are very useful as UV protectors in nature and as sunscreen reagents in daily life. They convert harmful UV energy to thermal energy through effective nonradiative decay (NRD) including trans → cis photoisomerization. However, the mechanism is not simple because different photoisomeirzation routes have been observed for different substituted cinnamates. Here, we theoretically examined the substitution effects at the phenyl ring of methylcinnamate (MC), a non-substituted cinnamate, on the electronic structure and the NRD route involving trans → cis isomerization based on time-dependent density functional theory. A systematic reaction pathway search using the single-component artificial force-induced reaction method shows that the very efficient photoisomerization route of MC can be essentially described as "1ππ* (trans) → 1nπ* → T1 (3ππ*) → S0 (trans or cis)". We found that for efficient 1ππ* (trans) → 1nπ* internal conversion (IC), MC should have the substituent at the appropriate position of the phenyl ring to stabilize the highest occupied π orbital. Substitution at the para position of MC slightly lowers the 1ππ* state energy and photoisomerization occurs via a slightly less efficient "1ππ* (trans) → 3nπ* → T1 (3ππ*) → S0 (trans or cis)" pathway. Substitution at the meta or ortho positions of MC significantly lowers the 1ππ* state energy so that the energy barrier of IC (1ππ* → 1nπ*) becomes very high. This substitution leads to a much longer 1ππ* state lifetime than that of MC and para-substituted MC, and a change in the dominant photoisomerization route to "1ππ* (trans) → C[double bond, length as m-dash]C bond twisting on 1ππ* → S0 (trans or cis)". As a whole, the "1ππ* → 1nπ*" IC observed in MC is the most important initial step for the rapid change of UV energy to thermal energy. We also found that the stabilization of the π orbital (i) minimizes the energy gap between 1ππ* and 1nπ* at the 1ππ* minimum and (ii) makes the 0-0 level of 1ππ* higher than 1nπ* as observed in MC. These MC-like relationships between the 1ππ* and 1nπ* energies should be ideal to maximize the "1ππ* → 1nπ*" IC rate constant according to Marcus theory.
Collapse
Affiliation(s)
- Shin-Nosuke Kinoshita
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.
| | - Yu Harabuchi
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan and Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan
| | - Yoshiya Inokuchi
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.
| | - Satoshi Maeda
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan and Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan
| | - Masahiro Ehara
- SOKENDAI, the Graduate University for Advanced Studies, Myodaiji, Okazaki 444-8585, Japan and Institute for Molecular Science and Research Center for Computational Science, 38, Myodaiji, Okazaki 444-8585, Japan
| | - Kaoru Yamazaki
- Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai, 980-8577, Japan.
| | - Takayuki Ebata
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.
| |
Collapse
|
14
|
Cercola R, Wong NGK, Rhodes C, Olijnyk L, Mistry NS, Hall LM, Berenbeim JA, Lynam JM, Dessent CEH. A “one pot” mass spectrometry technique for characterizing solution- and gas-phase photochemical reactions by electrospray mass spectrometry. RSC Adv 2021; 11:19500-19507. [PMID: 35479237 PMCID: PMC9033567 DOI: 10.1039/d1ra02581c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/17/2021] [Indexed: 12/28/2022] Open
Abstract
The characterization of new photochemical pathways is important to progress the understanding of emerging areas of light-triggered inorganic and organic chemistry. In this context, the development of platforms to perform routine characterization of photochemical reactions remains an important goal for photochemists. Here, we demonstrate a new instrument that can be used to characterise both solution-phase and gas-phase photochemical reactions through electrospray ionisation mass spectrometry (ESI-MS). The gas-phase photochemistry is studied by novel laser-interfaced mass spectrometry (LIMS), where the molecular species of interest is introduced to the gas-phase by ESI, mass-selected and then subjected to laser photodissociation in the ion-trap. On-line solution-phase photochemistry is initiated by LEDs prior to ESI-MS in the same instrument with ESI-MS again being used to monitor photoproducts. Two ruthenium metal carbonyls, [Ru(η5-C5H5)(PPh3)2CO][PF6] and [Ru(η5-C5H5)(dppe)CO][PF6] (dppe = 1,2-bis(diphenylphosphino)ethane) are studied using this methodology. We show that the gas-phase photofragmentation pathways observed for the ruthenium complexes via LIMS (i.e. loss of CO + PPh3 ligands from [Ru(η5-C5H5)(PPh3)2CO]+ and loss of just CO from [Ru(η5-C5H5)(dppe)CO]+) mirror the solution-phase photochemistry at 3.4 eV. The advantages of performing the gas-phase and solution-phase photochemical characterisations in a single instrument are discussed. The solution and gas-phase dissociative photochemistry of two ruthenium half-sandwich complexes are analysed with electrospray ionisation mass spectrometry in a novel instrument.![]()
Collapse
Affiliation(s)
| | | | - Chris Rhodes
- Department of Chemistry
- University of York
- York YO10 5DD
- UK
| | - Lorna Olijnyk
- Department of Chemistry
- University of York
- York YO10 5DD
- UK
| | | | - Lewis M. Hall
- Department of Chemistry
- University of York
- York YO10 5DD
- UK
| | | | - Jason M. Lynam
- Department of Chemistry
- University of York
- York YO10 5DD
- UK
| | | |
Collapse
|
15
|
Furlan C, Berenbeim JA, Dessent CEH. Photoproducts of the Photodynamic Therapy Agent Verteporfin Identified via Laser Interfaced Mass Spectrometry. Molecules 2020; 25:molecules25225280. [PMID: 33198255 PMCID: PMC7696214 DOI: 10.3390/molecules25225280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/08/2020] [Accepted: 11/09/2020] [Indexed: 12/12/2022] Open
Abstract
Verteporfin, a free base benzoporphyrin derivative monoacid ring A, is a photosensitizing drug for photodynamic therapy (PDT) used in the treatment of the wet form of macular degeneration and activated by red light of 689 nm. Here, we present the first direct study of its photofragmentation channels in the gas phase, conducted using a laser interfaced mass spectrometer across a broad photoexcitation range from 250 to 790 nm. The photofragmentation channels are compared with the collision-induced dissociation (CID) products revealing similar dissociation pathways characterized by the loss of the carboxyl and ester groups. Complementary solution-phase photolysis experiments indicate that photobleaching occurs in verteporfin in acetonitrile; a notable conclusion, as photoinduced activity in Verteporfin was not thought to occur in homogenous solvent conditions. These results provide unique new information on the thermal break-down products and photoproducts of this light-triggered drug.
Collapse
|
16
|
Berenbeim JA, Wong NGK, Cockett MCR, Berden G, Oomens J, Rijs AM, Dessent CEH. Sodium cationization can disrupt the intramolecular hydrogen bond that mediates the sunscreen activity of oxybenzone. Phys Chem Chem Phys 2020; 22:19522-19531. [PMID: 32840272 DOI: 10.1039/d0cp03152f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A key decay pathway by which organic sunscreen molecules dissipate harmful UV energy involves excited-state hydrogen atom transfer between proximal enol and keto functional groups. Structural modifications of this molecular architecture have the potential to block ultrafast decay processes, and hence promote direct excited-state molecular dissociation, profoundly affecting the efficiency of an organic sunscreen. Herein, we investigate the binding of alkali metal cations to a prototype organic sunscreen molecule, oxybenzone, using IR characterization. Mass-selective IR action spectroscopy was conducted at the free electron laser for infrared experiments, FELIX (600-1800 cm-1), on complexes of Na+, K+ and Rb+ bound to oxybenzone. The IR spectra reveal that K+ and Rb+ adopt binding positions away from the key OH intermolecular hydrogen bond, while the smaller Na+ cation binds directly between the keto and enol oxygens, thus breaking the intramolecular hydrogen bond. UV laser photodissociation spectroscopy was also performed on the series of complexes, with the Na+ complex displaying a distinctive electronic spectrum compared to those of K+ and Rb+, in line with the IR spectroscopy results. TD-DFT calculations reveal that the origin of the changes in the electronic spectra can be linked to rupture of the intramolecular bond in the sodium cationized complex. The implications of our results for the performance of sunscreens in mixtures and environments with high concentrations of metal cations are discussed.
Collapse
Affiliation(s)
- Jacob A Berenbeim
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
| | - Natalie G K Wong
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
| | - Martin C R Cockett
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
| | - Giel Berden
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, Nijmegen, The Netherlands
| | - Jos Oomens
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, Nijmegen, The Netherlands
| | - Anouk M Rijs
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, Nijmegen, The Netherlands
| | | |
Collapse
|
17
|
Cercola R, Fischer KC, Sherman SL, Garand E, Wong NGK, Hammerback LA, Lynam JM, Fairlamb IJS, Dessent CEH. Direct Measurement of the Visible to UV Photodissociation Processes for the PhotoCORM TryptoCORM. Chemistry 2020; 26:10297-10306. [PMID: 32275091 PMCID: PMC7496620 DOI: 10.1002/chem.202001077] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/08/2020] [Indexed: 11/22/2022]
Abstract
PhotoCORMs are light-triggered compounds that release CO for medical applications. Here, we apply laser spectroscopy in the gas phase to TryptoCORM, a known photoCORM that has been shown to destroy Escherichia coli upon visible-light activation. Our experiments allow us to map TryptoCORM's photochemistry across a wide wavelength range by using novel laser-interfaced mass spectrometry (LIMS). LIMS provides the intrinsic absorption spectrum of the photoCORM along with the production spectra of all of its ionic photoproducts for the first time. Importantly, the photoproduct spectra directly reveal the optimum wavelengths for maximizing CO ejection, and the extent to which CO ejection is compromised at redder wavelengths. A series of comparative studies were performed on TryptoCORM-CH3 CN which exists in dynamic equilibrium with TryptoCORM in solution. Our measurements allow us to conclude that the presence of the labile CH3 CN facilitates CO release over a wider wavelength range. This work demonstrates the potential of LIMS as a new methodology for assessing active agent release (e.g. CO, NO, H2 S) from light-activated prodrugs.
Collapse
Affiliation(s)
- Rosaria Cercola
- Department of ChemistryUniversity of YorkHeslingtonYorkYO10 5DDUK
| | | | - Summer L. Sherman
- Department of ChemistryUniversity of Wisconsin-MadisonMadisonWI53706USA
| | - Etienne Garand
- Department of ChemistryUniversity of Wisconsin-MadisonMadisonWI53706USA
| | | | | | - Jason M. Lynam
- Department of ChemistryUniversity of YorkHeslingtonYorkYO10 5DDUK
| | | | | |
Collapse
|
18
|
Observation of Enhanced Dissociative Photochemistry in the Non-Native Nucleobase 2-Thiouracil. Molecules 2020; 25:molecules25143157. [PMID: 32664261 PMCID: PMC7397253 DOI: 10.3390/molecules25143157] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/30/2020] [Accepted: 07/08/2020] [Indexed: 12/12/2022] Open
Abstract
We present the first study to measure the dissociative photochemistry of 2-thiouracil (2-TU), an important nucleobase analogue with applications in molecular biology and pharmacology. Laser photodissociation spectroscopy is applied to the deprotonated and protonated forms of 2-TU, which are produced in the gas-phase using electrospray ionization mass spectrometry. Our results show that the deprotonated form of 2-thiouracil ([2-TU-H]−) decays predominantly by electron ejection and hence concomitant production of the [2-TU-H]· free-radical species, following photoexcitation across the UVA-UVC region. Thiocyanate (SCN−) and a m/z 93 fragment ion are also observed as photodecay products of [2-TU-H]− but at very low intensities. Photoexcitation of protonated 2-thiouracil ([2-TU·H]+) across the same UVA-UVC spectral region produces the m/z 96 cationic fragment as the major photofragment. This ion corresponds to ejection of an HS· radical from the precursor ion and is determined to be a product of direct excited state decay. Fragment ions associated with decay of the hot ground state (i.e., the ions we would expect to observe if 2-thiouracil was behaving like UV-dissipating uracil) are observed as much more minor products. This behaviour is consistent with enhanced intersystem crossing to triplet excited states compared to internal conversion back to the ground state. These are the first experiments to probe the effect of protonation/deprotonation on thionucleobase photochemistry, and hence explore the effect of pH at a molecular level on their photophysical properties.
Collapse
|
19
|
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.
Collapse
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
| | | |
Collapse
|
20
|
Deng Z, Sun S, Zhou M, Huang G, Pang J, Dang L, Li MD. Revealing Ultrafast Energy Dissipation Pathway of Nanocrystalline Sunscreens Oxybenzone and Dioxybenzone. J Phys Chem Lett 2019; 10:6499-6503. [PMID: 31589456 DOI: 10.1021/acs.jpclett.9b02592] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Two widely used ultraviolet filters, oxybenzone and dioxybenzone, are applied in a variety of areas, particularly in sunscreen cosmetics. Ultrafast femtosecond transient absorption is utilized to trace the excited states and transient states of the nanocrystalline suspension and solution phase of these two molecules. The analysis reveals the intriguing discovery that the transient species of the oxybenzone nanocrystalline suspension have shorter lifetimes than that in solution. The energy dissipation mechanism of these molecules is simulated by density functional theory calculations, and the potential energy surface calculations and the single-crystal structure can well explain the fast decay dynamics of the nanocrystalline transient states of these two molecules.
Collapse
Affiliation(s)
- Ziqi Deng
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structure Materials of Guangdong Providence , Shantou University , Shantou 515063 , China
| | - Shanshan Sun
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structure Materials of Guangdong Providence , Shantou University , Shantou 515063 , China
| | - Miaomiao Zhou
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structure Materials of Guangdong Providence , Shantou University , Shantou 515063 , China
| | - Guanheng Huang
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structure Materials of Guangdong Providence , Shantou University , Shantou 515063 , China
| | - Junhong Pang
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structure Materials of Guangdong Providence , Shantou University , Shantou 515063 , China
| | - Li Dang
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structure Materials of Guangdong Providence , Shantou University , Shantou 515063 , China
| | - Ming-De Li
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structure Materials of Guangdong Providence , Shantou University , Shantou 515063 , China
- Chemistry and Chemical Engineering Guangdong Laboratory , Shantou 515031 , China
| |
Collapse
|
21
|
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
| | | |
Collapse
|
22
|
Direct Observation of Photochemical Free Radical Production from the Sunscreen 2‐Phenylbenzimidazole‐5‐Sulfonic Acid via Laser‐Interfaced Mass Spectrometry. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900149] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|