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Sedmidubská B, Kočišek J. Interaction of low-energy electrons with radiosensitizers. Phys Chem Chem Phys 2024; 26:9112-9136. [PMID: 38376461 DOI: 10.1039/d3cp06003a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
We provide an experimentalist's perspective on the present state-of-the-art in the studies of low-energy electron interactions with common radiosensitizers, including compounds used in combined chemo-radiation therapy and their model systems. Low-energy electrons are important secondary species formed during the interaction of ionizing radiation with matter. Their role in the radiation chemistry of living organisms has become an important topic for more than 20 years. With the increasing number of works and reviews in the field, we would like to focus here on a very narrow area of compounds that have been shown to have radio-sensitizing properties on the one hand, and high reactivity towards low-energy electrons on the other hand. Gas phase experiments studying electron attachment to isolated molecules and environmental effects on reaction dynamics are reviewed for modified DNA components, nitroimidazoles, and organometallics. In the end, we provide a perspective on the future directions that may be important for transferring the fundamental knowledge about the processes induced by low-energy electrons into practice in the field of rational design of agents for concomitant chemo-radiation therapy.
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Affiliation(s)
- Barbora Sedmidubská
- J. Heyrovský Institute of Physical Chemistry of the CAS, Dolejškova 3, 182223 Prague, Czech Republic.
- Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Břehová 7, 11519 Prague, Czech Republic
- Institut de Chimie Physique, UMR 8000 CNRS and Faculté des sciences d'Orsay, Université Paris Saclay, F-91405 Orsay Cedex, France
| | - Jaroslav Kočišek
- J. Heyrovský Institute of Physical Chemistry of the CAS, Dolejškova 3, 182223 Prague, Czech Republic.
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2
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Prasanthkumar KP, Valayankadan F, Aravindakumar CT, P A, Babu A, Alvarez-Idaboy JR. Identifying the Transients and Transformation Products in Hydroxyl Radical-Methimazole Reactions Using DFT and UPLC-Q-TOF MS/MS Approaches. J Phys Chem B 2024; 128:1448-1460. [PMID: 38320124 DOI: 10.1021/acs.jpcb.3c07913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Oxidative reactions of the hydroxyl radical (·OH) with methimazole (MMI), an antithyroid drug, are crucial for understanding its fate in oxidizing environments. By synergistically integrating density functional theory and ultraperformance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF MS/MS) techniques, we elucidated the transients and transformation products (TPs) arising from the ·OH-MMI reactions. We probed two hydrogen-atom abstraction (HA) reactions, three radical adduct formation reactions, and single electron transfer (SET) at the M06-2X/6-311++G(d,p)/SMD(water) level. All proposed reaction channels, except for HA from the methyl group and SET, were found to be barrier-free. SET is the dominant oxidation pathway, accounting for 44% of oxidations, as determined by branching ratio analysis. The selenium analogue, MSeI, exhibited minor reactivity differences compared to MMI, yet its overall patterns resembled those of ·OH-MMI reactions. TPs were generated experimentally by reacting MMI with ·OH produced by UV-photolysis of H2O2. Eight TPs were identified from an approximately 24% degradation of MMI using UPLC-Q-TOF MS/MS analysis, and an additional two TPs were identified from the approximately 52% degraded MMI sample. The exact identities of all of the TPs were established through their corresponding fragmentation patterns. This study elucidates the drug's susceptibility to free radical species under physiologically relevant conditions.
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Affiliation(s)
- Kavanal P Prasanthkumar
- Post Graduate and Research Department of Chemistry, Maharaja's College, Ernakulam 682 011, India
| | - Faseelath Valayankadan
- Post Graduate and Research Department of Chemistry, Maharaja's College, Ernakulam 682 011, India
| | - Charuvila T Aravindakumar
- School of Environmental Sciences, Mahatma Gandhi University, Kottayam 686 560, India
- Inter-University Instrumentation Centre, Mahatma Gandhi University, Kottayam 686 560, India
| | - Arun P
- Inter-University Instrumentation Centre, Mahatma Gandhi University, Kottayam 686 560, India
| | - Aswathy Babu
- Post Graduate and Research Department of Chemistry, Maharaja's College, Ernakulam 682 011, India
| | - Juan R Alvarez-Idaboy
- Departamento de Física y Química Teórica, Facultad de Química, Universidad Nacional Autónoma de México, México D. F. 04510, Mexico
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Cao Y, Liu J, Ma Q, Zhang C, Zhang P, Chen T, Wang Y, Chu B, Zhang X, Francisco JS, He H. Photoactivation of Chlorine and Its Catalytic Role in the Formation of Sulfate Aerosols. J Am Chem Soc 2024; 146:1467-1475. [PMID: 38186050 DOI: 10.1021/jacs.3c10840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
We present a novel mechanism for the formation of photocatalytic oxidants in deliquescent NaCl particles, which can greatly promote the multiphase photo-oxidation of SO2 to produce sulfate. The photoexcitation of the [Cl--H3O+-O2] complex leads to the generation of Cl and OH radicals, which is the key reason for enhancing aqueous-phase oxidation and accelerating SO2 oxidation. The mass normalization rate of sulfate production from the multiphase photoreaction of SO2 on NaCl droplets could be estimated to be 0.80 × 10-4 μg·h-1 at 72% RH and 1.33 × 10-4 μg·h-1 at 81% RH, which is equivalent to the known O3 liquid-phase oxidation mechanism. Our findings highlight the significance of multiphase photo-oxidation of SO2 on NaCl particles as a non-negligible source of sulfate in coastal areas. Furthermore, this study underscores the importance of Cl- photochemistry in the atmosphere.
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Affiliation(s)
- Yiqun Cao
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiarong Liu
- Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Qingxin Ma
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Chunyan Zhang
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Peng Zhang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Tianzeng Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yonghong Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Biwu Chu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Xiuhui Zhang
- Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Joseph S Francisco
- Department of Earth and Environmental Science and Department of Chemistry, University of Pennsylvania, Philadelphia,Pennsylvania 19104, United States
| | - Hong He
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
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Liu J, Liang D, Liu L, Ning A, Zhang X. Catalytic sulfate formation mechanism influenced by important constituents of cloud water via the reaction of SO 2 oxidized by hypobromic acid in marine areas. Phys Chem Chem Phys 2021; 23:15935-15949. [PMID: 34296723 DOI: 10.1039/d1cp01981c] [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
Comprehensive investigations of the possible formation pathways of sulfate, the main composition of atmospheric aerosol in marine areas, continue to challenge atmospheric chemists. As one of the most important oxidation routes of S(iv) contributing to sulfate formation, the reaction process of S(iv) oxidized by hypobromic acid, which is ubiquitous with the gas-phase mixing ratios of ∼310 ppt and has a well-known oxidative capacity, has attracted wide attention. However, little information is available about the detailed reaction mechanism. Especially, due to the abundant species in cloud water, the potential effect of these compositions on these reaction processes and the corresponding effect mechanism are also uncertain. Using high-level quantum chemical calculations, we theoretically elucidate the two-step mechanism of Br+ transfer proposed by experiment through the verification of the key BrSO3- intermediate formation and subsequent hydrolysis reaction or the uncovered reaction of BrSO3- intermediate with OH-. Further, the novel and more competitive mechanisms (OH+ or O atom transfer pathways) that have not been considered in previous studies, leading to sulfate formation directly, have been found. Furthermore, it should be mentioned that we revealed the effect mechanism of constituents catalyzed in cloud water, especially the important H2O-catalyzed mechanism. In addition, all the above pathways follow this catalytic mechanism. This finding indicates a linkage between the complex nature of the atmospheric constituents and related atmospheric reaction, as well as the enhanced occurrence of atmospheric secondary sulfate formation in the atmosphere. Hence, this exploration of sulfate formation related to hypobromic acid could provide a better understanding about the sources of sulfate in marine areas.
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Affiliation(s)
- Jiarong Liu
- Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
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Deng Y, Liu X, Zhao Y, Xue J, Zheng X. Resonance Raman spectroscopic and density functional theoretical study on microsolvated 2-Thiocytosine clusters with polar solvents. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 230:118043. [PMID: 31951865 DOI: 10.1016/j.saa.2020.118043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 12/31/2019] [Accepted: 01/05/2020] [Indexed: 06/10/2023]
Abstract
Microsolvation effects on the excited state deactivation dynamics of 2-thiocytosine (2tC) were studied in hydrogen-bonded 2tC clusters with protic solvents using resonance Raman, FT-IR, FT-Raman, UV-vis spectroscopy combining with density functional theoretical calculation. Two protic solvents, water (H2O) and methanol (MeOH), and one aprotic solvent, acetonitrile (MeCN), were used to investigate the 2tC(H2O)1-5, 2tC(MeOH)1-5, and 2tC(MeCN)1-3 microsolvated clusters. In CH3OH and H2O solvents, most of the Raman shifts were due to the vibration modes of 2tC(solvent)n (solvent = H2O, CH3OH; n = 1-4) clusters via intermolecular NH⋯O hydrogen bonds (HB). The intermolecular >NH⋯O hydrogen bond interactions, which are the key constituents of stable thione structure of 2tC, revealed the spectra difference of 2tC in CH3CN, CH3OH and H2O. With the aid of electronic structural and vibration frequency calculations, the observed Raman spectra were assigned to the low energy isomers of 2tC(solvent)2 (solvent = H2O, CH3OH) clusters in water and methanol and 2tC(CH3CN) in acetonitrile solvents. 2tC(solvent)2 clusters in water and methanol may prohibit or promote excited state proton transfer reaction from sulfur atom to neighbor nitrogen atom due to the hydrogen bonding chain between 2tC and protic solvent molecules. Our experimental and theoretical studies confirmed that the hydrogen bond sites were located on the specified functional group SCNH of 2tC with solvent molecules.
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Affiliation(s)
- Yaoliang Deng
- Department of Chemistry and Engineering Research Center for Eco-dyeing and Finishing of Textiles, Key Laboratory of Advanced Textiles Materials and Manufacture Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Xin Liu
- Department of Chemistry and Engineering Research Center for Eco-dyeing and Finishing of Textiles, Key Laboratory of Advanced Textiles Materials and Manufacture Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Yanying Zhao
- Department of Chemistry and Engineering Research Center for Eco-dyeing and Finishing of Textiles, Key Laboratory of Advanced Textiles Materials and Manufacture Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Jiadan Xue
- Department of Chemistry and Engineering Research Center for Eco-dyeing and Finishing of Textiles, Key Laboratory of Advanced Textiles Materials and Manufacture Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Xuming Zheng
- Department of Chemistry and Engineering Research Center for Eco-dyeing and Finishing of Textiles, Key Laboratory of Advanced Textiles Materials and Manufacture Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018, China
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Skotnicki K, Taras-Goslinska K, Janik I, Bobrowski K. Radiation Induced One-Electron Oxidation of 2-Thiouracil in Aqueous Solutions. Molecules 2019; 24:E4402. [PMID: 31810289 PMCID: PMC6930642 DOI: 10.3390/molecules24234402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 11/27/2019] [Accepted: 11/27/2019] [Indexed: 11/17/2022] Open
Abstract
Oxidative damage to 2-thiouracil (2-TU) by hydroxyl (•OH) and azide (●N3) radicals produces various primary reactive intermediates. Their optical absorption spectra and kinetic characteristics were studied by pulse radiolysis with UV-vis spectrophotometric and conductivity detection and by time-dependent density functional theory (TD-DFT) method. The transient absorption spectra recorded in the reactions of •OH with 2-TU depend on the concentration of 2-TU, however, only slightly on pH. At low concentrations, they are characterized by a broad absorption band with a weakly pronounced maxima located at λ = 325, 340 and 385 nm, whereas for high concentrations, they are dominated by an absorption band with λmax ≈ 425 nm. Based on calculations using TD-DFT method, the transient absorption spectra at low concentration of 2-TU were assigned to the ●OH-adducts to the double bond at C5 and C6 carbon atoms (3●, 4●) and 2c-3e bonded ●OH adduct to sulfur atom (1…●OH) and at high concentration of 2-TU also to the dimeric 2c-3e S-S-bonded radical in neutral form (2●). The dimeric radical (2●) is formed in the reaction of thiyl-type radical (6●) with 2-TU and both radicals are in an equilibrium with Keq = 4.2 × 103 M-1. Similar equilibrium (with Keq = 4.3 × 103 M-1) was found for pH above the pKa of 2-TU which involves admittedly the same radical (6●) but with the dimeric 2c-3e S-S bonded radical in anionic form (2●-). In turn, ●N3-induced oxidation of 2-TU occurs via radical cation with maximum spin location on the sulfur atom which subsequently undergoes deprotonation at N1 atom leading again to thiyl-type radical (6●). This radical is a direct precursor of dimeric radical (2●).
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Affiliation(s)
- Konrad Skotnicki
- Centre of Radiation Research and Technology, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland;
| | | | - Ireneusz Janik
- Notre Dame Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Krzysztof Bobrowski
- Centre of Radiation Research and Technology, Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland;
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Shinde RG, Khan AA, Barik A. Formation of two centre three electron bond by hydroxyl radical induced reaction of thiocoumarin: evidence from experimental and theoretical studies. Free Radic Res 2019; 53:629-640. [PMID: 31072168 DOI: 10.1080/10715762.2019.1617417] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Radiation chemical studies of thioesculetin (1), a thioketone derivative of coumarin, were performed by both pulse radiolysis technique and DFT calculations. Hydroxyl (•OH) radical reaction with 1 resulted transients absorbing at 320, 360 and 500 nm. To identify the nature of the transients, the reaction was studied with specific one-electron oxidant (N3•) radical, where 360 nm band was absent. The transient absorption at 500 nm was concentration-dependent. The overall impression for •OH radical reaction was that the transient absorbing at 320, 360 and 500 nm was due to sulphur centred monomer radical, hydroxysulfuranyl and dimer radical of 1 respectively. The equilibrium constant between the monomer to dimer radical was 3.75 × 104 M-1. From the transients' redox nature, it was observed that 57 and 24% of •OH radical yielded to oxidising and reducing products respectively. Further, the product analysis by HPLC suggested that the dimer radical disproportionate to esculetin and thioesculetin. DFT energy calculation for all the possible transients revealed that dimer radical has the lowest energy. The HOMO of 1 and its monomer radical suggested that the electron density was localised on the sulphur atom. The bond length between the two sulphur atoms in dimer radical was 2.88 Å which was less than the van der Waals distance. Bond order between the two sulphur atoms was 0.55, suggesting that the bond was two centre three electron (2c-3e). From TD-DFT calculation, the electronic transition of dimer radical was at 479 nm which was in close agreement with the experimental value. The nature of the electronic transition was σ → σ* from a 2c - 3e bond.
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Affiliation(s)
- Rupali G Shinde
- a Department of Chemistry , Savitribai Phule Pune University , Pune , India.,b Radiation and Photochemistry Division , Bhabha Atomic Research Centre , Mumbai , India
| | - Ayesha A Khan
- a Department of Chemistry , Savitribai Phule Pune University , Pune , India
| | - Atanu Barik
- b Radiation and Photochemistry Division , Bhabha Atomic Research Centre , Mumbai , India
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