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Amador CK, Vyas S, Strathmann TJ. Kinetic Model for Predicting Perfluoroalkyl Acid Degradation During UV-Sulfite Treatment. Environ Sci Technol 2024; 58:6425-6434. [PMID: 38554136 DOI: 10.1021/acs.est.3c10584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/01/2024]
Abstract
Hydrated electron (eaq-) treatment processes show great potential in remediating recalcitrant water contaminants, including perfluoroalkyl and polyfluoroalkyl substances (PFAS). However, treatment efficacy depends upon many factors relating to source water composition, UV light source characteristics, and contaminant reactivity. Here, we provide critical insights into the complex roles of solution parameters on contaminant abatement through application of a UV-sulfite kinetic model that incorporates first-principles information on eaq- photogeneration and reactivity. The model accurately predicts decay profiles of short-chain perfluoroalkyl acids (PFAAs) during UV-sulfite treatment and facilitates quantitative interpretation of the effects of changing solution composition on PFAS degradation rates. Model results also confirm that the enhanced degradation of PFAAs observed under highly alkaline pH conditions results from changes in speciation of nontarget eaq- scavengers. Reverse application of the model to UV-sulfite data collected for longer chain PFAAs enabled estimation of bimolecular rate constants (k2, M-1 s-1), providing an alternative to laser flash photolysis (LFP) measurements that are not feasible due to the water solubility limitations of these compounds. The proposed model links the disparate means of investigating eaq- processes, namely, UV photolysis and LFP, and provides a framework to estimate UV-sulfite treatment efficacy of PFAS in diverse water sources.
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Affiliation(s)
- Camille K Amador
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Shubham Vyas
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Timothy J Strathmann
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
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2
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Amador CK, Cavalli H, Tenorio R, Tetu H, Higgins CP, Vyas S, Strathmann TJ. Influence of Carbonate Speciation on Hydrated Electron Treatment Processes. Environ Sci Technol 2023; 57:7849-7857. [PMID: 37170785 DOI: 10.1021/acs.est.2c09451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Advanced reduction processes (ARPs) that generate hydrated electrons (eaq-; e.g., UV-sulfite) have emerged as a promising remediation technology for recalcitrant water contaminants, including per- and polyfluoroalkyl substances (PFASs). The effectiveness of ARPs in different natural water matrices is determined, in large part, by the presence of non-target water constituents that act to quench eaq- or shield incoming UV photons from the applied photosensitizer. This study examined the pH-dependent quenching of eaq- by ubiquitous dissolved carbonate species (H2CO3*, HCO3-, and CO32-) and quantified the relative importance of carbonate species to other abundant quenching agents (e.g., H2O, H+, HSO3-, and O2(aq)) during ARP applications. Analysis of laser flash photolysis kinetic data in relation to pH-dependent carbonate acid-base speciation yields species-specific bimolecular rate constants for eaq- quenching by H2CO3*, HCO3-, and CO32- (kH2CO3* = 2.23 ± 0.42 × 109 M-1 s-1, kHCO3- = 2.18 ± 0.73 × 106 M-1 s-1, and kCO32- = 1.05 ± 0.61 × 105 M-1 s-1), with quenching dominated by H2CO3* (which includes both CO2(aq) and H2CO3) at moderately alkaline pH conditions despite it being the minor species. Attempts to apply previously reported rate constants for eaq- quenching by CO2(aq), measured in acidic solutions equilibrated with CO2(g), overpredict quenching observed in this study at higher pH conditions typical of ARP applications. Moreover, kinetic simulations reveal that pH-dependent trends reported for UV-sulfite ARPs that have often been attributed to eaq- quenching by varying [H+] can instead be ascribed to variable acid-base speciation of dissolved carbonate and the sulfite sensitizer.
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Affiliation(s)
- Camille K Amador
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Haden Cavalli
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Raul Tenorio
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Hanna Tetu
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Christopher P Higgins
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Shubham Vyas
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Timothy J Strathmann
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States
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3
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Sierra S, Dalmau D, Alegre-Requena JV, Pop A, Silvestru C, Marín ML, Boscá F, Urriolabeitia EP. Synthesis of Bis(amino acids) Containing the Styryl-cyclobutane Core by Photosensitized [2+2]-Cross-cycloaddition of Allylidene-5(4 H)-oxazolones. Int J Mol Sci 2023; 24:ijms24087583. [PMID: 37108745 PMCID: PMC10140832 DOI: 10.3390/ijms24087583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/15/2023] [Accepted: 04/17/2023] [Indexed: 04/29/2023] Open
Abstract
The irradiation of 2-aryl-4-(E-3'-aryl-allylidene)-5(4H)-oxazolones 1 with blue light (456 nm) in the presence of [Ru(bpy)3](BF4)2 (bpy = 2,2'-bipyridine, 5% mol) gives the unstable cyclobutane-bis(oxazolones) 2 by [2+2]-photocycloaddition of two oxazolones 1. Each oxazolone contributes to the formation of 2 with a different C=C bond, one of them reacting through the exocyclic C=C bond, while the other does so through the styryl group. Treatment of unstable cyclobutanes 2 with NaOMe/MeOH produces the oxazolone ring opening reaction, affording stable styryl-cyclobutane bis(amino acids) 3. The reaction starts with formation of the T1 excited state of the photosensitizer 3[Ru*(bpy)3]2+, which reacts with S0 of oxazolones 1 through energy transfer to give the oxazolone T1 state 3(oxa*)-1, which is the reactive species and was characterized by transient absorption spectroscopy. Measurement of the half-life of 3(oxa*)-1 for 1a, 1b and 1d shows large values for 1a and 1b (10-12 μs), while that of 1d is shorter (726 ns). Density functional theory (DFT) modeling displays strong structural differences in the T1 states of the three oxazolones. Moreover, study of the spin density of T1 state 3(oxa*)-1 provides clues to understanding the different reactivity of 4-allylidene-oxazolones described here with respect to the previously reported 4-arylidene-oxazolones.
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Affiliation(s)
- Sonia Sierra
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain
| | - David Dalmau
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain
| | - Juan V Alegre-Requena
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain
| | - Alexandra Pop
- Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC), Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, 400028 Cluj-Napoca, Romania
| | - Cristian Silvestru
- Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC), Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, 400028 Cluj-Napoca, Romania
| | - Maria Luisa Marín
- Instituto Universitario Mixto de Tecnología Química (ITQ-UPV), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, 46022 València, Spain
| | - Francisco Boscá
- Instituto Universitario Mixto de Tecnología Química (ITQ-UPV), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, 46022 València, Spain
| | - Esteban P Urriolabeitia
- Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain
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Becerra R, Cannady JP, Walsh R. Time-resolved, Gas-phase Kinetic and Quantum Chemical Studies of the Reaction of Germylene with Hydrogen Chloride. Chemphyschem 2023; 24:e202200902. [PMID: 36806423 DOI: 10.1002/cphc.202200902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 02/23/2023]
Abstract
Time-resolved studies of germylene, GeH2 , generated by laser flash photolysis of 3,4-dimethyl-1-germacyclopent-3-ene at 193 nm and monitored by laser absorption, have been carried out to obtain rate constants for its bimolecular reaction with HCl. The reaction was studied in the gas phase, mainly at a total pressure of 10 Torr (in SF6 bath gas) at five temperatures in the range 295-558 K. Experiments at other pressures showed that these rate constants were unaffected by pressure. The second-order rate constants at 10 Torr (SF6 bath gas) fitted the Arrhenius equation: log(k/cm3 molecule-1 s-1 )=(-12.06±0.14)+(2.58±1.03 kJ mol-1 )/RTln10 where the uncertainties are single standard deviations. Quantum chemical calculations at G4 level support a mechanism in which an initial weakly bound donor-acceptor complex is formed. This can then rearrange and decompose to give H2 and HGeCl (chlorogermylene). The enthalpy barrier (36 kJ mol-1 ) is too high to allow rearrangement of the complex to GeH3 Cl (chlorogermane).
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Affiliation(s)
- Rosa Becerra
- Instituto de Quimica-Fisica 'Rocasolano' C.S.I.C., C/Serrano 119, 28006, Madrid, Spain
| | - J Pat Cannady
- Dow Chemical Company, 2030 Dow Center, Midland, MI-48674, USA
| | - Robin Walsh
- Department of Chemistry, University of Reading Whiteknights, P.O. Box 224, Reading, RG6 6AD, UK
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5
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Lino V, Manini P, Galeotti M, Salamone M, Bietti M, Crescenzi O, Napolitano A, d'Ischia M. Antioxidant Activities of Hydroxylated Naphthalenes: The Role of Aryloxyl Radicals. Chempluschem 2023; 88:e202200449. [PMID: 36680302 DOI: 10.1002/cplu.202200449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/09/2023] [Indexed: 01/12/2023]
Abstract
Herein is delineated a first systematic framework for the definition of structure-antioxidant property relationships in the dihydroxynaphthalene (DHN) series. The results obtained by a combined experimental and theoretical approach revealed that 1,8-DHN is the best performing antioxidant platform, with its unique hydrogen-bonded peri-hydroxylation pattern contributing to a fast H atom transfer process. Moreover, the comparative analysis of the antioxidant properties of DHNs carried out by performing DPPH and FRAP assays and laser flash photolysis experiments, revealed the higher antioxidant power associated with an α-substitution pattern (i. e. in 1,8- and 1,6-DHN) with respect to DHNs exhibiting a β-substitution pattern (i. e. in 2,6- and 2,7-DHN). DFT calculations and isolation and characterization of the main oligomer intermediates formed during the oxidative polymerization of DHNs supported this evidence by providing unprecedented insight into the generation and fate of the intermediate naphthoxyl radicals, which emerged as the main factor governing the antioxidant activity of DHNs.
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Affiliation(s)
- Valeria Lino
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126, Pisa, Italy.,Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, 80126, Napoli, Italy
| | - Paola Manini
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, 80126, Napoli, Italy
| | - Marco Galeotti
- Dipartimento di Scienze e Tecnologie Chimiche, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Michela Salamone
- Dipartimento di Scienze e Tecnologie Chimiche, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Massimo Bietti
- Dipartimento di Scienze e Tecnologie Chimiche, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Orlando Crescenzi
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, 80126, Napoli, Italy
| | - Alessandra Napolitano
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, 80126, Napoli, Italy
| | - Marco d'Ischia
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, 80126, Napoli, Italy
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6
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Liu Z, Chen Z, Gao J, Yu Y, Men Y, Gu C, Liu J. Accelerated Degradation of Perfluorosulfonates and Perfluorocarboxylates by UV/Sulfite + Iodide: Reaction Mechanisms and System Efficiencies. Environ Sci Technol 2022; 56:3699-3709. [PMID: 35226468 PMCID: PMC9481055 DOI: 10.1021/acs.est.1c07608] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The addition of iodide (I-) in the UV/sulfite system (UV/S) significantly accelerated the reductive degradation of perfluorosulfonates (PFSAs, CnF2n+1SO3-) and perfluorocarboxylates (PFCAs, CnF2n+1COO-). Using the highly recalcitrant perfluorobutane sulfonate (C4F9SO3-) as a probe, we optimized the UV/sulfite + iodide system (UV/S + I) to degrade n = 1-7 PFCAs and n = 4, 6, 8 PFSAs. In general, the kinetics of per- and polyfluoroalkyl substance (PFAS) decay, defluorination, and transformation product formations in UV/S + I were up to three times faster than those in UV/S. Both systems achieve a similar maximum defluorination. The enhanced reaction rates and optimized photoreactor settings lowered the EE/O for PFCA degradation below 1.5 kW h m-3. The relatively high quantum yield of eaq- from I- made the availability of hydrated electrons (eaq-) in UV/S + I and UV/I two times greater than that in UV/S. Meanwhile, the rapid scavenging of reactive iodine species by SO32- made the lifetime of eaq- in UV/S + I eight times longer than that in UV/I. The addition of I- also substantially enhanced SO32- utilization in treating concentrated PFAS. The optimized UV/S + I system achieved >99.7% removal of most PFSAs and PFCAs and >90% overall defluorination in a synthetic solution of concentrated PFAS mixtures and NaCl. We extended the discussion over molecular transformation mechanisms, development of PFAS degradation technologies, and the fate of iodine species.
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Affiliation(s)
- Zekun Liu
- Department
of Chemical & Environmental Engineering, University of California, Riverside, California 92521, United States
| | - Zhanghao Chen
- State
Key Laboratory of Pollution Control and Resource Reuse, School of
the Environment, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Jinyu Gao
- Department
of Chemical & Environmental Engineering, University of California, Riverside, California 92521, United States
| | - Yaochun Yu
- Department
of Chemical & Environmental Engineering, University of California, Riverside, California 92521, United States
- Department
of Civil & Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yujie Men
- Department
of Chemical & Environmental Engineering, University of California, Riverside, California 92521, United States
- Department
of Civil & Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Cheng Gu
- State
Key Laboratory of Pollution Control and Resource Reuse, School of
the Environment, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Jinyong Liu
- Department
of Chemical & Environmental Engineering, University of California, Riverside, California 92521, United States
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Marciniak B, Bobrowski K. Photo- and Radiation-Induced One-Electron Oxidation of Methionine in Various Structural Environments Studied by Time-Resolved Techniques. Molecules 2022; 27:1028. [PMID: 35164293 DOI: 10.3390/molecules27031028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 11/25/2022] Open
Abstract
Oxidation of methionine (Met) is an important reaction that plays a key role in protein modifications during oxidative stress and aging. The first steps of Met oxidation involve the creation of very reactive and short-lived transients. Application of complementary time-resolved radiation and photochemical techniques (pulse radiolysis and laser flash photolysis together with time-resolved CIDNP and ESR techniques) allowed comparing in detail the one-electron oxidation mechanisms initiated either by ●OH radicals and other one-electron oxidants or the excited triplet state of the sensitizers e.g., 4-,3-carboxybenzophenones. The main purpose of this review is to present various factors that influence the character of the forming intermediates. They are divided into two parts: those inextricably related to the structures of molecules containing Met and those related to external factors. The former include (i) the protection of terminal amine and carboxyl groups, (ii) the location of Met in the peptide molecule, (iii) the character of neighboring amino acid other than Met, (iv) the character of the peptide chain (open vs cyclic), (v) the number of Met residues in peptide and protein, and (vi) the optical isomerism of Met residues. External factors include the type of the oxidant, pH, and concentration of Met-containing compounds in the reaction environment. Particular attention is given to the neighboring group participation, which is an essential parameter controlling one-electron oxidation of Met. Mechanistic aspects of oxidation processes by various one-electron oxidants in various structural and pH environments are summarized and discussed. The importance of these studies for understanding oxidation of Met in real biological systems is also addressed.
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Wan D, Wang J, Dionysiou DD, Kong Y, Yao W, Selvinsimpson S, Chen Y. Photogeneration of Reactive Species from Biochar-Derived Dissolved Black Carbon for the Degradation of Amine and Phenolic Pollutants. Environ Sci Technol 2021; 55:8866-8876. [PMID: 34165300 DOI: 10.1021/acs.est.1c01942] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Due to agricultural waste combustion and large-scale biochar application, biochar-derived dissolved black carbon (DBC) is largely released into surface waters. The photogeneration of reactive species (RS) from DBC plays an important role in organic pollutant degradation. However, the mechanistic interactions between RS and pollutants are poorly understood. Here, we investigated the formation of DBC triplet states (3DBC*), singlet oxygen (1O2), and hydroxyl radical (•OH) in straw biochar-derived DBC solutions and photodegradation of typical pharmaceuticals and personal care products (PPCPs). Laser flash photolysis and electron spin resonance spectrometry showed that DBC exhibited higher RS quantum yields than some well-studied dissolved organic matter. The RS caused rapid degradation of atenolol, diphenhydramine, and propylparaben, selected as target PPCPs in this study. The 3DBC* contributed primarily to the oxidation of selected PPCPs via one-electron-transfer interaction, with average reaction rate constants of 1.15 × 109, 1.41 × 109, and 0.51 × 109 M-1 s-1, respectively. •OH also participated in the degradation and accounted for approximately 2.7, 2.5, and 18.0% of the total removal of atenolol, diphenhydramine, and propylparaben, respectively. Moreover, the photodegradation products were identified using high-resolution mass spectrometry, which further confirmed the electron transfer and •OH oxidation mechanisms. These findings suggest that DBC from the combustion process of agricultural biomass can efficiently induce the photodegradation of organic pollutants under sunlight in aquatic environments.
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Affiliation(s)
- Dong Wan
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Jie Wang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Dionysios D Dionysiou
- Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Yaqian Kong
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Wanying Yao
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | | | - Yong Chen
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
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9
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Zheng L, Dai X, Su H, Greenberg MM. Independent Generation and Time-Resolved Detection of 2'-Deoxyguanosin-N2-yl Radicals. Angew Chem Int Ed Engl 2020; 59:13406-13413. [PMID: 32365264 PMCID: PMC7395871 DOI: 10.1002/anie.202005300] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 05/01/2020] [Indexed: 12/25/2022]
Abstract
Guanine radicals are important reactive intermediates in DNA damage. Hydroxyl radical (HO. ) has long been believed to react with 2'-deoxyguanosine (dG) generating 2'-deoxyguanosin-N1-yl radical (dG(N1-H). ) via addition to the nucleobase π-system and subsequent dehydration. This basic tenet was challenged by an alternative mechanism, in which the major reaction of HO. with dG was proposed to involve hydrogen atom abstraction from the N2-amine. The 2'-deoxyguanosin-N2-yl radical (dG(N2-H). ) formed was proposed to rapidly tautomerize to dG(N1-H). . We report the first independent generation of dG(N2-H). in high yield via photolysis of 1. dG(N2-H). is directly observed upon nanosecond laser flash photolysis (LFP) of 1. The absorption spectrum of dG(N2-H). is corroborated by DFT studies, and anti- and syn-dG(N2-H). are resolved for the first time. The LFP experiments showed no evidence for tautomerization of dG(N2-H). to dG(N1-H). within hundreds of microseconds. This observation suggests that the generation of dG(N1-H). via dG(N2-H). following hydrogen atom abstraction from dG is unlikely to be a major pathway when HO. reacts with dG.
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Affiliation(s)
- Liwei Zheng
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, 21218, USA
| | - Xiaojuan Dai
- Department of Chemistry, Beijing Normal University, Beijing, 100875, P. R. China
| | - Hongmei Su
- Department of Chemistry, Beijing Normal University, Beijing, 100875, P. R. China
| | - Marc M Greenberg
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, 21218, USA
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10
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Pedzinski T, Bobrowski K, Marciniak B, Filipiak P. Unexpected Reaction Pathway of the Alpha-Aminoalkyl Radical Derived from One-Electron Oxidation of S-Alkylglutathiones. Molecules 2020; 25:E877. [PMID: 32079230 DOI: 10.3390/molecules25040877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 02/11/2020] [Accepted: 02/12/2020] [Indexed: 11/17/2022] Open
Abstract
Laser flash photolysis and high-resolution mass spectrometry were used to investigate the mechanism of one-electron oxidation of two S-alkylglutathiones using 3-carboxybenzophenone (3CB) as a photosensitizer. This report indicates an unexpected reaction pathway of the α-aminoalkyl radical cation (αN+) derived from the oxidation of S-alkylglutathiones. Instead of a common hydrolysis reaction of αN+ reported earlier for methionine and other sulfur-containing aminoacids and peptides, an intramolecular ring-closure reaction was found for S-alkylglutathiones.
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11
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Taras-Goslinska K, Vetica F, Barata-Vallejo S, Triantakostanti V, Marciniak B, Chatgilialoglu C. Converging Fate of the Oxidation and Reduction of 8-Thioguanosine. Molecules 2019; 24:E3143. [PMID: 31470553 DOI: 10.3390/molecules24173143] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 11/16/2022] Open
Abstract
Thione-containing nucleobases have attracted the attention of the scientific community for their application in oncology, virology, and transplantology. The detailed understanding of the reactivity of the purine derivative 8-thioguanosine (8-TG) with reactive oxygen species (ROS) and free radicals is crucial for its biological relevance. An extensive investigation on the fate of 8-TG under both reductive and oxidative conditions is here reported, and it was tested by employing steady-state photooxidation, laser flash photolysis, as well as γ-radiolysis in aqueous solutions. The characterization of the 8-TG T1 excited state by laser flash photolysis and the photooxidation experiments confirmed that singlet oxygen is a crucial intermediate in the formation of the unexpected reduced product guanosine, without the formation of the usual oxygenated sulfinic or sulfonic acids. Furthermore, a thorough screening of different radiolytic conditions upon γ-radiation afforded the reduced product. These results were rationalized by performing control experiments in the predominant presence of each reactive species formed by radiolysis of water, and the mechanistic pathway scenario was postulated on these bases.
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12
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Luo T, Wang Z, Wang Y, Liu Z, P Pozdnyakov I. Different Role of Bisulfite/Sulfite in UVC-S(IV)-O 2 System for Arsenite Oxidation in Water. Molecules 2019; 24:E2307. [PMID: 31234408 PMCID: PMC6631152 DOI: 10.3390/molecules24122307] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 06/12/2019] [Accepted: 06/14/2019] [Indexed: 11/17/2022] Open
Abstract
It is of interest to use UV-sulfite based processes to degrade pollutants in wastewater treatment process. In this work, arsenic (As(III)) has been selected as a target pollutant to verify the efficacy of such a hypothesized process. The results showed that As(III) was quickly oxidized by a UV-sulfite system at neutral or alkaline pH and especially at pH 9.5, which can be mainly attributed to the generated oxysulfur radicals. In laser flash photolysis (LFP) experiments (λex = 266 nm), the signals of SO3•- and eaq- generated by photolysis of sulfite at 266 nm were discerned. Quantum yields for photoionization of HSO3- (0.01) and SO32- (0.06) were also measured. It has been established that eaq- does not react with SO32-, but reacts with HSO3- with a rate constant 8 × 107 M-1s-1.
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Affiliation(s)
- Tao Luo
- Department of Environmental Science and Engineering, School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China.
| | - Zhenhua Wang
- Department of Environmental Science and Engineering, School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China.
| | - Yi Wang
- School of Civil Engineering, Engineering Research Center of Urban Disasters Prevention and Fire Rescue Technology of Hubei Province, Wuhan University, Wuhan 430072, China.
| | - Zizheng Liu
- School of Civil Engineering, Engineering Research Center of Urban Disasters Prevention and Fire Rescue Technology of Hubei Province, Wuhan University, Wuhan 430072, China.
| | - Ivan P Pozdnyakov
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, 630090 Novosibirsk, Russia.
- Novosibirsk State University, Pirogova str. 2, 630090 Novosibirsk, Russia.
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Miro P, Gomez-Mendoza M, Sastre G, Cuquerella MC, Miranda MA, Marin ML. Generation of the Thymine Triplet State by Through-Bond Energy Transfer. Chemistry 2019; 25:7004-7011. [PMID: 30920069 DOI: 10.1002/chem.201900830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Indexed: 01/12/2023]
Abstract
Benzophenone (BP) and drugs containing the BP chromophore, such as the non-steroidal anti-inflammatory drug ketoprofen, have been widely reported as DNA photosensitizers through triplet-triplet energy transfer (TTET). In the present work, a direct spectroscopic fingerprint for the formation of the thymine triplet (3 Thy*) by through-bond (TB) TTET from 3 BP* has been uncovered. This has been achieved in two new systems that have been designed and synthesized with one BP and one thymine (Thy) covalently linked to the two ends of the rigid skeleton of the natural bile acids cholic and lithocholic acid. The results shown here prove that it is possible to achieve triplet energy transfer to a Thy unit even when the photosensitizer is at a long (nonbonding) distance.
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Affiliation(s)
- Paula Miro
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior, de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022, Valencia, Spain
| | - Miguel Gomez-Mendoza
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior, de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022, Valencia, Spain
- Present address: Photoactivated Processes Unit, IMDEA Energy Institute, Avda Ramon de la Sagra 3, 28935 Mostoles, Madrid, Spain
| | - Germán Sastre
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior, de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022, Valencia, Spain
| | - M Consuelo Cuquerella
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior, de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022, Valencia, Spain
| | - Miguel A Miranda
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior, de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022, Valencia, Spain
| | - M Luisa Marin
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior, de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022, Valencia, Spain
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14
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Rodriguez-Muñiz GM, Miranda MA, Marin ML. A Time-Resolved Study on the Reactivity of Alcoholic Drinks with the Hydroxyl Radical. Molecules 2019; 24:E234. [PMID: 30634584 PMCID: PMC6359750 DOI: 10.3390/molecules24020234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 12/28/2018] [Accepted: 01/07/2019] [Indexed: 01/19/2023] Open
Abstract
Reactive oxygen species (ROS) can provoke damage to cells, where their concentrations are regulated by antioxidants. As the hydroxyl radical (•OH) is the most oxidizing ROS, we have focused our attention on the use of a mechanistically based time-resolved methodology, such as laser flash photolysis, to determine the relative reactivity of alcoholic beverages towards •OH as an indicator of their antioxidant potential. The selected drinks were of two different origins: (i) those derived from grapes such as red wine, white wine, white vermouth, marc and brandy and (ii) spirits not derived from grapes: triple sec, gin, whisky, and rum. Initially, we determined the quenching rate constant of ethanol with •OH and then we explored the reactivity of the different beverages, which was higher than expected based on their alcoholic content. This can be attributed to the presence of antioxidants and was especially remarkable for the grape-derived drinks.
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Affiliation(s)
- Gemma M Rodriguez-Muñiz
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avda. de los Naranjos s/n, E-46022 Valencia, Spain.
| | - Miguel A Miranda
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avda. de los Naranjos s/n, E-46022 Valencia, Spain.
| | - M Luisa Marin
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avda. de los Naranjos s/n, E-46022 Valencia, Spain.
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15
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Subervie D, Graff B, Nerkar S, Curran DP, Lalevée J, Lacôte E. Difluorination at Boron Leads to the First Electrophilic Ligated Boryl Radical (NHC-BF 2. ). Angew Chem Int Ed Engl 2018; 57:10251-10256. [PMID: 29928777 DOI: 10.1002/anie.201806476] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Indexed: 11/10/2022]
Abstract
1,3-Dimethylimidazol-2-ylidene difluoroborane (NHC-BF2 H) was prepared in a one-pot, two-step reaction from the parent ligated borane (NHC-BH3 ). The derived difluoroboryl radical (NHC-BF2. ) was generated by laser flash photolysis experiments and characterized by UV spectroscopy and rate-constant measurements. It is transient and reacts quickly with O2 . Unusually, it also reacts more rapidly with ethyl vinyl ether than with methyl acrylate. By this measure, it is the first electrophilic ligated boryl radical. Both NHC-BH3 and NHC-BF2 H serve as co-initiators in bulk photopolymerizations, converting both electron-poor and electron-rich monomers at roughly similar rates. However, the difluorinated coinitiator provides polymers with dramatically increased chain lengths from both monomers.
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Affiliation(s)
- Daniel Subervie
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, CNES, ArianeGroup, LHCEP, Bât. Raulin, 2 rue Victor Grignard, 69622, Villeurbanne, France
| | - Bernadette Graff
- Institut de Science des Matériaux de Mulhouse (IS2M), UMR CNRS 7361, Université de Haute Alsace, 15 rue Jean Starcky, 68057, Mulhouse, France
| | - Swapnil Nerkar
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Dennis P Curran
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Jacques Lalevée
- Institut de Science des Matériaux de Mulhouse (IS2M), UMR CNRS 7361, Université de Haute Alsace, 15 rue Jean Starcky, 68057, Mulhouse, France
| | - Emmanuel Lacôte
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, CNES, ArianeGroup, LHCEP, Bât. Raulin, 2 rue Victor Grignard, 69622, Villeurbanne, France
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Abstract
Photodegradation is one of the most important abiotic transformations for pesticides in the aquatic environment, and the high energy of sunlight causes characteristic reactions such as bond scission, cyclization, and rearrangement, which are scarcely observed in hydrolysis and microbial degradation. This review deals with direct photolysis via excitation of a pesticide by absorbing natural or artificial sunlight in order to know its basic photochemistry, and indirect photolysis meaning either sensitization by dissolved organic matters or oxidation by reactive oxygen species is basically excluded. Several experimental approaches including spectroscopic techniques together with theoretical calculations are first discussed from the viewpoint of the reaction mechanisms in direct photolysis. Then, the typical photoreactions of pesticides are summarized by chemical classes and/or functional groups and discussed as far as possible in relation to their mechanisms.
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Affiliation(s)
- Toshiyuki Katagi
- Environmental Health Science Laboratory, Sumitomo Chemical Co., Ltd
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17
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Nuin E, Pérez-Sala D, Lhiaubet-Vallet V, Andreu I, Miranda MA. Photosensitivity to Triflusal: Formation of a Photoadduct with Ubiquitin Demonstrated by Photophysical and Proteomic Techniques. Front Pharmacol 2016; 7:277. [PMID: 27621705 PMCID: PMC5002410 DOI: 10.3389/fphar.2016.00277] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 08/12/2016] [Indexed: 11/13/2022] Open
Abstract
Triflusal is a platelet aggregation inhibitor chemically related to acetylsalicylic acid, which is used for the prevention and/or treatment of vascular thromboembolisms, which acts as a prodrug. Actually, after oral administration it is absorbed primarily in the small intestine, binds to plasma proteins (99%) and is rapidly biotransformed in the liver into its deacetylated active metabolite 2-hydroxy-4-trifluoromethylbenzoic acid (HTB). In healthy humans, the half-life of triflusal is ca. 0.5 h, whereas for HTB it is ca. 35 h. From a pharmacological point of view, it is interesting to note that HTB is itself highly active as a platelet anti-aggregant agent. Indeed, studies on the clinical profile of both drug and metabolite have shown no significant differences between them. It has been evidenced that HTB displays ability to induce photoallergy in humans. This phenomenon involves a cell-mediated immune response, which is initiated by covalent binding of a light-activated photosensitizer (or a species derived therefrom) to a protein. In this context, small proteins like ubiquitin could be appropriate models for investigating covalent binding by means of MS/MS and peptide fingerprint analysis. In previous work, it was shown that HTB forms covalent photoadducts with isolated lysine. Interestingly, ubiquitin contains seven lysine residues that could be modified by a similar reaction. With this background, the aim of the present work is to explore adduct formation between the triflusal metabolite and ubiquitin as model protein upon sunlight irradiation, combining proteomic and photophysical (fluorescence and laser flash photolysis) techniques. Photophysical and proteomic analysis demonstrates monoadduct formation as the major outcome of the reaction. Interestingly, addition can take place at any of the ε-amino groups of the lysine residues of the protein and involves replacement of the trifluoromethyl moiety with a new amide function. This process can in principle occur with other trifluoroaromatic compounds and may be responsible for the appearance of undesired photoallergic side effects.
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Affiliation(s)
- Edurne Nuin
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas Valencia, Spain
| | - Dolores Pérez-Sala
- Departamento de Biología Físico-Química, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas Madrid, Spain
| | - Virginie Lhiaubet-Vallet
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas Valencia, Spain
| | - Inmaculada Andreu
- Unidad Mixta de Investigación IIS La Fe-UPV, Hospital Universitari i Politècnic La Fe Valencia, Spain
| | - Miguel A Miranda
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas Valencia, Spain
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18
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Gozzi F, Oliveira SC, Dantas RF, Silva VO, Quina FH, Machulek A. Kinetic studies of the reaction between pesticides and hydroxyl radical generated by laser flash photolysis. J Sci Food Agric 2016; 96:1580-1584. [PMID: 25974279 DOI: 10.1002/jsfa.7258] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 04/07/2015] [Accepted: 05/11/2015] [Indexed: 06/04/2023]
Abstract
BACKGROUND Due to contamination of the environment by pesticides and their mishandling, there is the need for treatment of contaminated sites and correct disposal of materials containing them. Thus, studies with advanced oxidation processes are expanding and can determine the rate constant of the hydroxyl radical with organic compounds of great importance in environmental contamination. In this context, the use of laser flash photolysis has been shown to be viable for the determination of these constants. RESULTS The reaction rate constants of different pesticides with HO(•) in degassed acetonitrile have been determined. They were 1.6 × 10(9) M(-1) s(-1), 0.6 × 10(9) M(-1) s(-1), 1.2 × 10(9) M(-1) s(-1), 2.4 × 10(9) M(-1) s(-1) and 2.2 × 10(9) M(-1) s(-1) for the pesticides carbaryl, propoxur, fenoxycarb, ethoxysulfuron and chlorimuron-ethyl, respectively. These values are about an order of magnitude smaller than the diffusion controlled rate and correlate with the relative rates of disappearance of the pesticides in the photo-Fenton reaction in water. CONCLUSION The correlation of the relative rate constants determined by laser flash photolysis with the relative rates of photo-Fenton degradation of the pesticides is compelling evidence for the participation of the hydroxyl radical in the degradation of these pesticides in the latter system.
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Affiliation(s)
- Fábio Gozzi
- Institute of Chemistry, Federal University of Mato Grosso do Sul, Av. Senador Filinto Muller 1555, CP 549, Campo Grande, MS, 79074-460, Brazil
| | - Silvio C Oliveira
- Institute of Chemistry, Federal University of Mato Grosso do Sul, Av. Senador Filinto Muller 1555, CP 549, Campo Grande, MS, 79074-460, Brazil
| | - Renato F Dantas
- School of Technology, University of Campinas UNICAMP, Paschoal Marmo 188, 13484-332, Limeira, SP, Brazil
| | - Volnir O Silva
- Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, CP 26077, São Paulo, SP, 05513-970, Brazil
| | - Frank H Quina
- Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, CP 26077, São Paulo, SP, 05513-970, Brazil
| | - Amilcar Machulek
- Institute of Chemistry, Federal University of Mato Grosso do Sul, Av. Senador Filinto Muller 1555, CP 549, Campo Grande, MS, 79074-460, Brazil
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19
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Lin SH, Fujitsuka M, Majima T. Dynamics of Excess-Electron Transfer through Alternating Adenine:Thymine Sequences in DNA. Chemistry 2015; 21:16190-4. [PMID: 26398266 DOI: 10.1002/chem.201503115] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Indexed: 12/16/2022]
Abstract
This paper presents the results of an investigation into the sequence-dependent excess-electron transfer (EET) dynamics in DNA, which plays an important role in DNA damage/repair. There are many published studies on EET in consecutive adenine:thymine (A:T) sequences (Tn), but those in alternating A:T sequences (ATn) remain limited. Here, two series of functionalized DNA oligomers, Tn and ATn, were synthesized with a strongly electron-donating photosensitizer, a trimer of ethylenedioxythiophene (3 E), and an electron acceptor, diphenylacetylene (DPA). Laser flash photolysis experiments showed that the EET rate constant of AT3 is two times lower than that of T3 due to the lack of π-stacking of Ts in AT3. Thus, it was indicated that excess-electron hopping is affected by the interaction between LUMOs of nucleotides.
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Affiliation(s)
- Shih-Hsun Lin
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047 (Japan), Fax: (+81) 6-6879-8499
| | - Mamoru Fujitsuka
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047 (Japan), Fax: (+81) 6-6879-8499.
| | - Tetsuro Majima
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047 (Japan), Fax: (+81) 6-6879-8499.
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20
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Ye J, Fujiwara Y, Abe M. Substituent effect on the energy barrier for σ-bond formation from π-single-bonded species, singlet 2,2-dialkoxycyclopentane-1,3-diyls. Beilstein J Org Chem 2013; 9:925-33. [PMID: 23766808 PMCID: PMC3678856 DOI: 10.3762/bjoc.9.106] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 04/22/2013] [Indexed: 11/23/2022] Open
Abstract
Background: Localized singlet diradicals are in general quite short-lived intermediates in processes involving homolytic bond-cleavage and formation reactions. In the past decade, long-lived singlet diradicals have been reported in cyclic systems such as cyclobutane-1,3-diyls and cyclopentane-1,3-diyls. Experimental investigation of the chemistry of singlet diradicals has become possible. The present study explores the substituents and the effect of their substitution pattern at the C(1)–C(3) positions on the lifetime of singlet octahydropentalene-1,3-diyls to understand the role of the substituents on the reactivity of the localized singlet diradicals. Results: A series of singlet 2,2-dialkoxy-1,3-diaryloctahydropentalene-1,3-diyls DR were generated in the photochemical denitrogenation of the corresponding azoalkanes AZ. The ring-closed products CP, i.e., 3,3-dialkoxy-2,4-diphenyltricyclo[3.3.0.02,4]octanes, were quantitatively obtained in the denitrogenation reaction. The first-order decay process (k = 1/τ) was observed for the fate of the singlet diradicals DR (λmax ≈ 580–590 nm). The activation parameters, ΔH‡ and ΔS‡, for the ring-closing reaction (σ-bond formation process) were determined by the temperature-dependent change of the lifetime. The energy barrier was found to be largely dependent upon the substituents Ar and Ar’. The singlet diradical DRf (Ar = 3,5-dimethoxyphenyl, OCH2Ar’ = OCH2(3,5-dimethoxyphenyl)) was the longest-lived, τ293 = 5394 ± 59 ns, among the diradicals studied here. The lifetime of the parent diradical DR (Ar = Ph, OCH2Ar’ = OCH3) was 299 ± 2 ns at 293 K. Conclusion: The lifetimes of the singlet 1,3-diyls are found to be largely dependent on the substituent pattern of Ar and Ar’ at the C(1)–C(3) positions. Both the enthalpy and entropy effect were found to play crucial roles in increasing the lifetime.
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Affiliation(s)
- Jianhuai Ye
- Department of Chemistry, Graduate School of Science, Hiroshima University, Japan
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21
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Nuin E, Jiménez MC, Sastre G, Andreu I, Miranda MA. Drug-Drug Interactions within Protein Cavities Probed by Triplet-Triplet Energy Transfer. J Phys Chem Lett 2013; 4:1603-7. [PMID: 26282966 DOI: 10.1021/jz400640s] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A new direct and noninvasive methodology based on transient absorption spectroscopy has been developed to probe the feasibility of drug-drug interactions within a common protein binding site. The simultaneous presence of (R)-cinacalcet (CIN) and (S)-propranolol (PPN) within human or bovine α1-acid glycoproteins (AAGs) is revealed by detection of (3)CIN* as the only transient species after laser flash photolysis of CIN/PPN/AAG mixtures at 308 nm. This is the result of triplet-triplet energy transfer from (3)PPN* to CIN, which requires close contact between the two drugs within the same biological compartment. Similar results are obtained with nabumetone and CIN as donor/acceptor partners. This new methodology can, in principle, be extended to a variety of drug/drug/biomolecule combinations.
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Affiliation(s)
- Edurne Nuin
- †Departamento de Química-Instituto de Tecnología Química UPV-CSIC, Universidad Politécnica de Valencia, Camino de Vera s/n, Valencia, Spain
| | - M Consuelo Jiménez
- †Departamento de Química-Instituto de Tecnología Química UPV-CSIC, Universidad Politécnica de Valencia, Camino de Vera s/n, Valencia, Spain
| | - Germán Sastre
- †Departamento de Química-Instituto de Tecnología Química UPV-CSIC, Universidad Politécnica de Valencia, Camino de Vera s/n, Valencia, Spain
| | - Inmaculada Andreu
- ‡Unidad mixta de investigación IIS La Fe-UPV, Hospital La Fe, Avda. Campanar 21, 46009 Valencia, Spain
| | - Miguel A Miranda
- †Departamento de Química-Instituto de Tecnología Química UPV-CSIC, Universidad Politécnica de Valencia, Camino de Vera s/n, Valencia, Spain
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22
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Abstract
Cyanine fluorophores exhibit greatly improved photostability when covalently linked to stabilizers, such as cyclooctatetraene (COT), nitrobenzyl alcohol (NBA) or Trolox. However, the mechanism by which photostabilization is mediated has yet to be determined. Here we present spectroscopic evidence that COT, when covalently linked to Cy5, substantially reduces the lifetime of the Cy5 triplet state, and that the degree of triplet state quenching correlates with enhancements in photostability observed in single-molecule fluorescence measurements. By contrast, NBA and Trolox did not quench the Cy5 triplet state under our conditions suggesting that their mechanism of photostabilization is different from COT and does not target the fluorophore triplet state directly. These findings provide insights into the mechanisms of fluorophore photostabilization that may lead to improved fluorophore designs for biological imaging applications.
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Affiliation(s)
- Qinsi Zheng
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
- Tri-Institutional Training Program in Chemical Biology, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
| | - Steffen Jockusch
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Zhou Zhou
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
| | - Roger B. Altman
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
| | - J. David Warren
- Department of Biochemistry, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
| | - Nicholas J. Turro
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Scott C. Blanchard
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
- Tri-Institutional Training Program in Chemical Biology, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
- Department of Biochemistry, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
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Bose A, Dey D, Basu S. Laser flash photolysis and magnetic-field-effect studies on interaction of thymine and thymidine with menadione: role of sugar in controlling reaction pattern. Sci Technol Adv Mater 2008; 9:024205. [PMID: 27877956 PMCID: PMC5099713 DOI: 10.1088/1468-6996/9/2/024205] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 05/20/2008] [Accepted: 12/17/2007] [Indexed: 06/06/2023]
Abstract
The magnetic field effect (MFE) in conjunction with laser flash photolysis has been used for the study of the interaction of one of the small drug like quinone molecules, 2-methyl, 1,4-naphthoquinone, commonly known as menadione (MQ), with one of the DNA bases, thymine (THN), and its corresponding nucleoside, thymidine (THDN), in acetonitrile (ACN) and sodium dodecylsulfate (SDS) micelles. It has been observed that THN undergoes electron transfer (ET) and hydrogen (H) abstraction with MQ, while THDN undergoes only H abstraction in both the media. However, our earlier studies showed that a purine base, adenine (ADN), and its nucleoside, 2'-deoxyadenosine (ADS), undergo ET in ACN and H abstraction in SDS. Here we have attempted to explain the differences in the reactions of these DNA bases with MQ. We also reveal the crucial role of a sugar unit in altering the behavior of purine and pyrimidine bases with respect to ET and H abstraction.
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Affiliation(s)
| | | | - Samita Basu
- Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata – 700 064, India
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Dad S, Bisby R, Clark I, Parker A. Identification and reactivity of the triplet excited state of 5-hydroxytryptophan. J Photochem Photobiol B 2005; 78:245-51. [PMID: 15708522 PMCID: PMC1890304 DOI: 10.1016/j.jphotobiol.2004.11.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Revised: 11/22/2004] [Accepted: 11/22/2004] [Indexed: 11/28/2022]
Abstract
Both the neurotransmitter serotonin and the unnatural amino acid 5-hydroxytryptophan (5HT), contain the 5-hydroxyindole chromophore. The photochemistry of 5HT is being investigated in relation to the multiphoton excitation of this chromophore to produce a characteristic photoproduct with green fluorescence ('hyperluminescence'). Laser flash photolysis (308 nm) of 5HT in aqueous solution at neutral pH produces both the neutral 5-indoloxyl radical (lambda(max) 400-420 nm) and another transient absorption with lambda(max) 480 nm and lifetime of 2 micros in deaerated solutions. Based on quenching by oxygen and beta-carotene, the species at 480 nm is identified as the triplet excited state of 5HT. In acidic solution a new oxygen-insensitive intermediate with lambda(max) 460 is assigned to the radical cation of 5HT. Time-resolved measurements of luminescence at 1270 nm have shown that the triplet state of 5HT is able to react with oxygen to form singlet excited oxygen (1O2*) with a quantum yield of approximately 0.1. However, 5HT has also been found to be an effective quencher of singlet oxygen with a second order rate constant of 1.3 x 10(8) dm3 mol(-1) s(-1). The results are discussed in the light of recent observations on the multiphoton-excited photochemistry of serotonin.
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Affiliation(s)
- S. Dad
- Biosciences Research Institute, University of Salford, Salford M5 4WT, UK
| | - R.H. Bisby
- Biosciences Research Institute, University of Salford, Salford M5 4WT, UK
| | - I.P. Clark
- Lasers for Science Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK
| | - A.W. Parker
- Lasers for Science Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK
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