51
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Dong MM, Rosario-Ortiz FL. Photochemical formation of hydroxyl radical from effluent organic matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:3788-94. [PMID: 22352464 DOI: 10.1021/es2043454] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The photochemical formation of hydroxyl radical (HO•) from effluent organic matter (EfOM) was evaluated using three bulk wastewater samples collected at different treatment facilities under simulated sunlight. For the samples studied, the formation rates of HO•(R(HO•)) were obtained from the formation rate of phenol following the hydroxylation of benzene. The values of R(HO•) ranged from 2.3 to 3.8 × 10(-10) M s(-1) for the samples studied. The formation rate of HO• from nitrate photolysis (R(NO3)(HO•)) was determined to be 3.0 × 10(-7) M(HO)• M(NO3)(-1) s(-1). The HO• production rate from EfOM (R(EfOM)(HO•)) ranged from 0.76 to 1.3 × 10(-10) M s(-1). For the wastewater samples studied, R(EfOM)(HO•) varied from 1.5 to 2.4 × 10(-7) M(HO)• M(C)(-1) (s-1) on molarcarbon basis, which was close to HO• production from nitrate photolysis. The apparent quantum yield for the formation of HO• from nitrate (Φ(NO3-HO•)(a)) was determined as 0.010 ± 0.001 for the wavelength range 290-400 nm in ultrapure water. The apparent quantum yield for HO• formation in EfOM (Φ(EfOM-HO•)(a)) ranged from 6.1 to 9.8 × 10(-5), compared to 2.99 to 4.56 × 10(-5) for organic matter (OM) isolates. The results indicate that wastewater effluents could produce significant concentrations of HO•, as shown by potential higher nitrate levels and relatively higher quantum yields of HO• formation from EfOM.
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Affiliation(s)
- Mei Mei Dong
- Department of Civil, Environmental and Architectural Engineering, University of Colorado, Boulder, Boulder, Colorado 80309, United States
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52
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Gombár M, Józsa É, Braun M, Ősz K. Construction of a photochemical reactor combining a CCD spectrophotometer and a LED radiation source. Photochem Photobiol Sci 2012; 11:1592-5. [DOI: 10.1039/c2pp25166c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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53
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Bedini A, De Laurentiis E, Sur B, Maurino V, Minero C, Brigante M, Mailhot G, Vione D. Phototransformation of anthraquinone-2-sulphonate in aqueous solution. Photochem Photobiol Sci 2012; 11:1445-53. [DOI: 10.1039/c2pp25111f] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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54
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55
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Liu N, Sun G. Production of Reactive Oxygen Species by Photoactive Anthraquinone Compounds and Their Applications in Wastewater Treatment. Ind Eng Chem Res 2011. [DOI: 10.1021/ie101423v] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Ning Liu
- Division of Textiles and Clothing, University of California, Davis, California 95616, United States
| | - Gang Sun
- Division of Textiles and Clothing, University of California, Davis, California 95616, United States
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56
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Liu N, Sun G. Photoinduced decolorization of 2, 6-dichloroindophenol by 2-anthraquinone sulfonate treated nylon. ACS APPLIED MATERIALS & INTERFACES 2011; 3:1221-1227. [PMID: 21355579 DOI: 10.1021/am200047a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Photoactive 2-anthraquinone sulfonate sodium (2-AQS) can produce hydroxyl radical and other reactive oxygen species under UVA irradiation. Because of its acid dye like feature, 2-AQS was immobilized onto nylon fibers through an acid dyeing process, and the dyed nylon was employed as a photoactive self-cleaning material. As a model study, decolorization of representative colorants such as 2,6-dichloroindophenol (DCIP) by the material was investigated. The results revealed that DCIP was first absorbed on the fibers and then degraded by hydroxyl radicals and other reactive oxygen species generated by 2-AQS on the surfaces upon UVA exposure. The photo degradation pathway of DCIP was further studied by directly using aqueous 2-AQS solution, and the degraded products in the solutions were analyzed by LC-MS. Different light sources and hydrogen donors were investigated in degradation of DCIP. The photoactive functions on the 2-AQS-dyed nylon fibers were quite durable and maintained similar decolorization effect of DCIP after five repeated tests.
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Affiliation(s)
- Ning Liu
- Fiber and Polymer Science, University of California, Davis, California 95616, USA
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57
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Du Y, Fu QS, Li Y, Su Y. Photodecomposition of 4-chlorophenol by reactive oxygen species in UV/air system. JOURNAL OF HAZARDOUS MATERIALS 2011; 186:491-496. [PMID: 21126819 DOI: 10.1016/j.jhazmat.2010.11.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 11/01/2010] [Accepted: 11/07/2010] [Indexed: 05/30/2023]
Abstract
In this article, the photo-degradation of 4-chlorophenol (4-CP) under UV irradiation was studied with focus on the photodecomposition of 4-CP by reactive oxygen species (ROS). 4-CP underwent much faster and more complete degradation in UV/air system than in UV/N(2) system. In UV/air system, the addition of t-butanol, a well-known (•)OH scavenger, significantly impeded the degradation of 4-CP. In the presence of t-butanol, the tendencies for the degradation of 4-CP and the formation of intermediates in UV/air system were very similar to those in UV/N(2) system. In UV/air system, 4-CP was degraded by two pathways, direct photolysis by absorbing the photons and the oxidation via •OH. The contribution of direct photolysis and the oxidation via •OH to 4-CP decomposition were 17.2% and 82.8%, respectively based on the apparent kinetic constants. Hydrogen peroxide, which could produce •OH through photolysis, was formed in UV/air system. It was shown that dissolved oxygen, organic matter in excited state and hydrogen ion are all necessary for the formation of hydrogen peroxide. The formation mechanism of H(2)O(2) was proposed based on experimental evidence.
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Affiliation(s)
- Yingxun Du
- Nanjing Institute of Geography and Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing, China.
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58
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Liu N, Sun G, Zhu J. Photo-induced self-cleaning functions on 2-anthraquinone carboxylic acid treated cotton fabrics. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm12805a] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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59
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Maurino V, Bedini A, Borghesi D, Vione D, Minero C. Phenol transformation photosensitised by quinoid compounds. Phys Chem Chem Phys 2011; 13:11213-21. [DOI: 10.1039/c1cp20355j] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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60
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Görner H. Reduction of 4,4′-Stilbenequinone and 4,4′-Diphenoquinone upon Reaction with Photogenerated Radicals. Photochem Photobiol 2010; 86:1202-7. [DOI: 10.1111/j.1751-1097.2010.00798.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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61
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Sirtori C, Agüera A, Gernjak W, Malato S. Effect of water-matrix composition on Trimethoprim solar photodegradation kinetics and pathways. WATER RESEARCH 2010; 44:2735-2744. [PMID: 20206373 DOI: 10.1016/j.watres.2010.02.006] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 02/03/2010] [Accepted: 02/03/2010] [Indexed: 05/28/2023]
Abstract
Direct photolysis and solar TiO(2) photocatalysis of Trimethoprim (TMP) in different water matrices (demineralised and simulated seawater) have been studied. Direct photolysis yielded a similar, slow TMP degradation rate in both water matrices, and the formation of very stable photo-transformation products. Dissolved organic carbon decreased slightly after prolonged irradiation. The main intermediate identified was a ketone derivative (trimethoxybenzoylpyrimidine), which was proved to be a photosensitizer of TMP degradation. During TiO(2) photocatalysis, TMP was completely eliminated in both water matrices at a similar rate, however, the mineralization rate was appreciably reduced in seawater, which can be explained by the presence of inorganic species acting as hydroxyl radical scavengers, and directly affecting photocatalytic efficiency. Identification of intermediates showed differences between the two processes but hydroxylation, demethylation and cleavage of the original drug molecule were observed in both.
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Affiliation(s)
- Carla Sirtori
- Pesticide Residue Research Group, University of Almería, Carretera Sacramento s/n, La Cañada, Almería, Spain.
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62
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Barbafina A, Latterini L, Carlotti B, Elisei F. Characterization of Excited States of Quinones and Identification of Their Deactivation Pathways. J Phys Chem A 2010; 114:5980-4. [DOI: 10.1021/jp911734x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Arianna Barbafina
- Department of Chemistry and Centro di Eccellenza sui Materiali Innovativi Nanostrutturati (CEMIN), via Elce di Sotto 8, Perugia 06123, Italy
| | - Loredana Latterini
- Department of Chemistry and Centro di Eccellenza sui Materiali Innovativi Nanostrutturati (CEMIN), via Elce di Sotto 8, Perugia 06123, Italy
| | - Benedetta Carlotti
- Department of Chemistry and Centro di Eccellenza sui Materiali Innovativi Nanostrutturati (CEMIN), via Elce di Sotto 8, Perugia 06123, Italy
| | - Fausto Elisei
- Department of Chemistry and Centro di Eccellenza sui Materiali Innovativi Nanostrutturati (CEMIN), via Elce di Sotto 8, Perugia 06123, Italy
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63
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Görner H, Gruen H. Direct and ketone-sensitized photoconversion of 1-nitro-9,10-anthraquinone to 1-amino-9,10-anthraquinone mediated by donor radicals. Chem Phys 2010. [DOI: 10.1016/j.chemphys.2009.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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64
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Maddigapu PR, Bedini A, Minero C, Maurino V, Vione D, Brigante M, Mailhot G, Sarakha M. The pH-dependent photochemistry of anthraquinone-2-sulfonate. Photochem Photobiol Sci 2010; 9:323-30. [DOI: 10.1039/b9pp00103d] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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65
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Gruen H, Görner H. Reduction of the polynuclear quinonoid dyes 16,17-dihydroxy- and dimethoxyviolanthrone with photogenerated radicals. Photochem Photobiol Sci 2009; 8:1164-71. [DOI: 10.1039/b907913k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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66
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67
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Isolation and structure elucidation of the major photodegradation products of seratrodast. J Pharm Biomed Anal 2008; 48:78-84. [DOI: 10.1016/j.jpba.2008.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2008] [Revised: 04/25/2008] [Accepted: 05/05/2008] [Indexed: 11/17/2022]
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68
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Gruen H, Görner H. Photoreduction of 2-methyl-1-nitro-9,10-anthraquinone in the presence of 1-phenylethanol. Photochem Photobiol Sci 2008; 7:1344-52. [PMID: 18958321 DOI: 10.1039/b811372f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photoreactions of 1-nitro-9,10-anthraquinone (N1) and 2-methyl-1-nitro-9,10-anthraquinone (N2) were studied in benzene and acetonitrile in the presence of 1-phenylethanol. For N2, a short-lived 10 ns transient observed upon flash photolysis is attributed to a triplet state, which can be intercepted by 1-phenylethanol to form a monohydro radical of N2 and a spectroscopically not detectable donor-derived radical. The decay of radicals yields the corresponding nitroso compound and eventually 1-amino-2-methyl-9,10-anthraquinone (A2) as photoproduct. The final reduction step requires participation of the anthraquinone carbonyl groups. The yield of radicals and the quantum yield (Phi(NH(2))) of conversion to A2 are small in inert solvents and increase with the donor concentration, approaching Phi(NH(2)) = 0.2. No triplet state was observed in the flash photolysis of N1, but a N1-derived radical and 1-amino-9,10-anthraquinone (A1) as final products were found. Various mechanistic aspects of complete photoreduction of nitroarenes to aminoarenes are discussed.
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Affiliation(s)
- Henry Gruen
- Max-Planck-Institut für Bioanorganische Chemie, Mülheim an der Ruhr, Germany
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69
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Alegria AE, Inostroza Y, Kumar A. Photosensitized oxidation of hypoxanthine and xanthine by aluminum phthalocyanine tetrasulfonate. Role of the alkylating quinone 2,5-dichloro-diaziridinyl-1,4-benzoquinone. Photochem Photobiol 2008; 84:1583-8. [PMID: 18627517 DOI: 10.1111/j.1751-1097.2008.00389.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photoirradiation of nitrogen-saturated aqueous solutions containing aluminum phthalocyanine tetrasulfonate (AlPcS4) at 675 nm in the presence of 2,5-dichloro-diaziridinyl-1,4-benzoquinone (AZDClQ) and hypoxanthine (HX) produces the oxidized HX derivatives, xanthine (X) and uric acid (UA). Concentrations of the AZDClQ semiquinone, X and UA increase at the expense of HX with an increase in irradiation time. Almost negligible decomposition of HX, as well as very low amounts of X, are detected if photolysis occurs under identical conditions but in the absence of AZDClQ. Addition of calf-thymus DNA produces quinone-DNA covalent adducts after photolysis of anaerobic samples containing quinone, DNA and AlPcS4, in the presence or absence of HX and at pH 5.5. However, larger amounts of quinone-DNA adducts are detected if HX is present. The results presented here could have applications in the photodynamic treatment of hypoxic tissues such as solid tumors, under conditions of high HX concentration, where Type-I pathways could be more important than singlet oxygen generation.
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Affiliation(s)
- Antonio E Alegria
- Department of Chemistry, University of Puerto Rico at Humacao, Humacao, Puerto Rico.
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70
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Gan D, Jia M, Vaughan PP, Falvey DE, Blough NV. Aqueous Photochemistry of Methyl-Benzoquinone. J Phys Chem A 2008; 112:2803-12. [DOI: 10.1021/jp710724e] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daqing Gan
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
| | - Min Jia
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
| | - Pamela P. Vaughan
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
| | - Daniel E. Falvey
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
| | - Neil V. Blough
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
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71
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Maurino V, Borghesi D, Vione D, Minero C. Transformation of phenolic compounds upon UVA irradiation of anthraquinone-2-sulfonate. Photochem Photobiol Sci 2008; 7:321-7. [DOI: 10.1039/b709331d] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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72
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Netto-Ferreira JC, Lhiaubet-Vallet V, Bernardes BO, Ferreira ABB, Miranda MÁ. Characterization, reactivity and photosensitizing properties of the triplet excited state of α-lapachone. Phys Chem Chem Phys 2008; 10:6645-52. [DOI: 10.1039/b810413a] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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73
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Sánchez-Polo M, Rivera-Utrilla J, Méndez-Díaz JD, Canonica S, von Gunten U. Photooxidation of naphthalenesulfonic acids: comparison between processes based on O(3), O(3)/activated carbon and UV/H(2)O(2). CHEMOSPHERE 2007; 68:1814-20. [PMID: 17493660 DOI: 10.1016/j.chemosphere.2007.03.050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 03/15/2007] [Accepted: 03/20/2007] [Indexed: 05/15/2023]
Abstract
The aim of the present study was to analyze and compare the efficacy of UV photodegradation with that of different advanced oxidation processes (O(3), UV/H(2)O(2), O(3)/activated carbon) in the degradation of naphthalenesulfonic acids from aqueous solution and to investigate the kinetics and the mechanism involved in these processes. Results obtained showed that photodegradation with UV radiation (254 nm) of 1-naphthalenesulfonic, 1,5-naphthalendisulfonic and 1,3,6-naphthalentrisulfonic acids is not effective. Presence of duroquinone and 4-carboxybenzophenone during UV irradiation (308-410 nm) of the naphthalenesulfonic acids increased the photodegradation rate. Addition of H(2)O(2) during irradiation of naphthalenesulfonic acids accelerated their elimination, due to the generation of ()OH radicals in the medium. Comparison between UV photodegradation 254 m and the advanced oxidation processes (O(3), O(3)/activated carbon and UV/H(2)O(2)) showed the low-efficacy of the former in the degradation of these compounds from aqueous medium. Thus, among the systems studied, those based on the use of UV/H(2)O(2) and O(3)/activated carbon were the most effective in the oxidation of these contaminants from the medium. This is because of the high-reactivity of naphthalenesulfonic acids with the *OH radicals generated by these two systems. This was confirmed by the values of the reaction rate constant of *OH radicals with these compounds k(OH), obtained by competitive kinetics (5.7 x 10(9) M(-1) s(-1), 5.2 x 10(9) M(-1) s(-1) and 3.7 x 10(9) M(-1) s(-1) for NS, NDS and NTS, respectively).
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Affiliation(s)
- M Sánchez-Polo
- Departamento de Química Inorgánica, Campus Fuentenueva s/n, Universidad de Granada, 18071 Granada, Spain
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74
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Görner H. Electron transfer from aromatic amino acids to triplet quinones. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2007; 88:83-9. [PMID: 17604179 DOI: 10.1016/j.jphotobiol.2007.05.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Revised: 05/03/2007] [Accepted: 05/03/2007] [Indexed: 10/23/2022]
Abstract
The photoreduction of 1,4-benzoquinone, 1,4-naphthoquinone, 9,10-anthraquinone (AQ) and several methylated or halogenated derivatives in argon-saturated acetonitrile-water mixtures by indole, N-acetyltryptophan and N-acetyltyrosine was studied by time-resolved UV-vis spectroscopy using 20 ns UV laser pulses. The quinone triplet state is quenched by the aromatic amino acids and the rate constants are (1-5)x10(9)M(-1)s(-1). The semiquinone radical anion Q.(-) is the major observable transient after electron transfer from amino acids to the quinone triplet state. Termination of Q.(-) and amino acid derived radicals takes place in the mus-ms range. The effects of structure and other specific properties of quinones and amino acids are discussed. The radicals are subjects of intercept with oxygen, whereby hydrogen peroxide is eventually formed. The quantum yield of oxygen uptake Phi(-O2) as a measure of formation of hydrogen peroxide increases with increasing amino acid concentration, approaching Phi(-O2) for AQ in air-saturated solution.
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Affiliation(s)
- Helmut Görner
- Max-Planck-Institut für Bioanorganische Chemie, D-45413 Mülheim an der Ruhr, Germany.
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75
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Görner H. Photoreduction of 9,10-Anthraquinone Derivatives: Transient Spectroscopy and Effects of Alcohols and Amines on Reactivity in Solution¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2003)0770171poadts2.0.co2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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76
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Görner H. Photoreduction of p-Benzoquinones: Effects of Alcohols and Amines on the Intermediates and Reactivities in Solution¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2003)0780440popeoa2.0.co2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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77
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Görner H. Photoreactions of 1,4-Naphthoquinones: Effects of Substituents and Water on the Intermediates and Reactivity¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb00197.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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78
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Garg S, Rose AL, Waite TD. Production of Reactive Oxygen Species on Photolysis of Dilute Aqueous Quinone Solutions. Photochem Photobiol 2007; 83:904-13. [PMID: 17645662 DOI: 10.1111/j.1751-1097.2007.00075.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have examined the generation of the reactive oxygen species (ROS) superoxide and hydrogen peroxide (H2O2) by irradiation of dilute aqueous solutions of disodium anthraquinone-2-6-disulfonate (AQDS) with simulated sunlight. Irradiating a solution of AQDS in 2 mM NaHCO3 and 0.01 M NaCl produced superoxide and H2O2 at nanomolar concentrations. Experiments in which initial concentrations of dioxygen, H2O2, the superoxide radical trap nitroblue tetrazolium and the electron donor dimethyl sulfoxide were varied suggested that the interaction of solvent water with photo-excited quinone moieties produces dioxygen-reducing radicals, and that these are the primary source of ROS in the system. A kinetic model for ROS production is proposed based on our experimental data.
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Affiliation(s)
- Shikha Garg
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW, Australia
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79
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Theoretical study on the photochemical properties of naphthazarin and halogen substitution. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.theochem.2006.09.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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80
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Tanabe K, Iida H, Haruna KI, Kamei T, Okamoto A, Nishimoto SI. Electrochemical evaluation of alternating duplex-triplex conversion effect on the anthraquinone-photoinjected hole transport through DNA duplex immobilized on a gold electrode. J Am Chem Soc 2006; 128:692-3. [PMID: 16417338 DOI: 10.1021/ja0568244] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Amperometry was employed to characterize the anthraquinone (AQ)-photoinjected hole transport through a 20-mer oligodeoxynucleotide (ODN) duplex, as immobilized on the surface of a gold electrode, and its triplex forms converted by association with several third oligopyrimidine (OPD) short strands. While the cathodic photocurrent was observed upon irradiation at 365 nm of the AQ photosensitizer linked to the end of DNA duplex, a marked lowering of the current density was identified to occur by the triplex formation of a duplex with a given third OPD short strand. The photocurrent through the DNA duplex showed a reversible fall-rise response concomitant with alternating association-dissociation cycle of the OPD short-strand, as regulated by temperature change around the corresponding melting temperature of the DNA triplex. Both the switched photoirradiation and the thermally alternating duplex-triplex conversion could provide tools of regulating the DNA hole transport.
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Affiliation(s)
- Kazuhito Tanabe
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Katsura Campus, Kyoto 615-8510, Japan.
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81
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Görner H. Photoinduced oxygen uptake for 9,10-anthraquinone in air-saturated aqueous acetonitrile in the presence of formate, alcohols, ascorbic acid or amines. Photochem Photobiol Sci 2006; 5:1052-8. [PMID: 17077902 DOI: 10.1039/b606968a] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photolysis of 9,10-anthraquinone (AQ), 2-methyl- and 2,3-dimethyl-AQ was studied in air-saturated acetonitrile-water in the presence of various donors: formate, ascorbic acid, alcohols, e.g. 2-propanol or methanol, and amines, e.g. ethylenediaminetetraacetate (EDTA). The photoreaction is initiated by H-atom or electron transfer from the donor to the AQ triplet state. The conversion of oxygen into hydrogen peroxide occurs via the superoxide radical and its conjugate acid. The quantum yield of oxygen uptake (Phi(-O2)) increases with increasing donor concentration. Phi(-O2) = 0.3-0.6 in the presence of 1 M 2-propanol and 3-10 mM ascorbic acid or EDTA. The properties of the quinone and donor radicals involved and the pH and concentration dependences of Phi(-O2) are described.
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Affiliation(s)
- Helmut Görner
- Max-Planck-Institut für Bioanorganische Chemie, D-45413, Mülheim an der Ruhr, Germany
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Görner H. Photoreactions of p-Quinones with Dimethyl Sulfide and Dimethyl Sulfoxide in Aqueous Acetonitrile†. Photochem Photobiol 2006; 82:71-7. [PMID: 16076243 DOI: 10.1562/2005-05-25-ra-540] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The effects of dimethyl sulfide (DMS) and dimethyl sulfoxide (DMSO) on the photoreactions of 1,4-benzoquinone (BQ), 1,4-naphthoquinone (NQ), 9,10-anthraquinone (AQ) and several derivatives in acetonitrile/water were studied. The observed triplet state of the quinones is quenched and the rate constant is close to the diffusion-controlled limit for reactions of most quinones with DMS and lower with DMSO. Semiquinone radical anions (Q*-) produced by electron transfer from sulfur to the triplet quinone were detected. For both DMS and DMSO the yield of Q*- is similar, being generally low for BQ and NQ, substantial for AQ and largest for chloranil. The specific quencher concentrations and the effects of quinone structure and redox potentials on the time-resolved photochemical properties are discussed.
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Affiliation(s)
- Helmut Görner
- Max-Planck-Institut für Bioanorganische Chemie, D-45413 Mülheim an der Ruhr, Germany
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85
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Görner H. Photoreactions of 1,4-Naphthoquinones: Effects of Substituents and Water on the Intermediates and Reactivity¶. Photochem Photobiol 2005. [DOI: 10.1562/2004-08-11-ra-270.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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86
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Latour V, Pigot T, Simon M, Cardy H, Lacombe S. Photo-oxidation of di-n-butylsulfide by various electron transfer sensitizers in oxygenated acetonitrile. Photochem Photobiol Sci 2005; 4:221-9. [PMID: 15696241 DOI: 10.1039/b413865c] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The selective activation of different photosensitizers has been carried out under comparable conditions and their efficiency towards di-n-butylsulfide oxidation in oxygenated acetonitrile compared from the product distribution after 150 minutes of irradiation. As expected, the best selectivity towards sulfoxide is obtained with a conventional energy transfer sensitizer such as Rose Bengal (RB), but also with a quinone with a low-lying triplet state, 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil or CHLO) and with 9,10-dicyanoanthracene (DCA). More significant yields in sulfonic and sulfuric acids are obtained under sensitization with 9,10-anthraquinone (ANT) or a derivative of benzophenone, 4-benzoyl benzoic acid (4-BB), with which additional experiments were carried out in order to discuss the involvement of either singlet oxygen or superoxide radical anion. Triphenyl pyrylium tetrafluoroborate (TPT+) is inefficient under the selected conditions and sulfide photo-oxidation can only be achieved with higher TPT+ concentrations with simultaneous total TPT+ bleaching. With TPT+, 1,2,4,5-tetracyanobenzene (TCNB) and TiO2, the product distribution and the low selectivity as well as the formation of numerous common by-products are indicative of radical mechanisms. All these results are discussed according to the possible formation of activated oxygen species, such as singlet oxygen, superoxide radical anion or alkylperoxy radicals.
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Affiliation(s)
- Virginie Latour
- Laboratoire de Chimie Theorique et de Physico-Chimie Moleculaire, UMR CNRS 5624, Universite de Pau, BP 1155, 64013, Pau cedex, France
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87
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Okamoto A, Kamei T, Tanaka K, Saito I. Photostimulated Hole Transport through a DNA Duplex Immobilized on a Gold Electrode. J Am Chem Soc 2004; 126:14732-3. [PMID: 15535693 DOI: 10.1021/ja0449067] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Photostimulated hole transport through DNA duplexes immobilized on gold electrodes has been investigated. By modifying a gold electrode with a DNA duplex containing a photosensitizer, we have observed a sequence-dependent cathodic photocurrent. DNA acts as a good mediator for cathodic photocurrent when appropriate sequences are selected.
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Affiliation(s)
- Akimitsu Okamoto
- Department of Synthetic Chemistry and Biological Chemistry, Faculty of Engineering, Kyoto University, Kyoto 615-8510, Japan.
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88
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Brezová V, Dvoranová D, Kost'álová D. Oxygen activation by photoexcited protoberberinium alkaloids fromMahonia aquifolium. Phytother Res 2004; 18:640-6. [PMID: 15476305 DOI: 10.1002/ptr.1512] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Protoberberinium salts, i.e. berberine (I), palmatine (II) and jatrorrhizine (III) prepared from Mahonia aquifolium (Pursh) Nutt. belong to isoquinoline alkaloids possessing interesting biological activity (e.g. antibacterial, antimalarial, antitumor). The characteristic UV/Vis absorption band maxima of I-III iodide salts were found in regions 350 and 425 nm in dimethylsulfoxide (DMSO) and ethanol solvents, and were only negligibly influenced by substitution changes on the C-2 and C-3 positions. The fluorescence intensity of protoberberinium salts monitored in ethanol solutions was significantly lowered by iodide counter-ions, and decreased in the order berberine > palmatine > jatrorrhizine. EPR spectroscopy supplied evidence of the formation of super-oxide anion radicals and singlet oxygen upon irradiation of berberine in oxygenated DMSO solvent. The photochemical generation of O(2) (.-) and (1)O(2) in DMSO solutions of palmatine and jatrorrhizine was substantially lower, and probably reflected the replacement of a photolabile methylenedioxy group at C-2 and C-3 positions in the berberine molecule by two methoxy groups in palmatine, and methoxyl (C-2) and hydroxyl (C-3) substitution in jatrorrhizine. Additionally, the powder EPR spectra of protoberberinium iodides I-III measured at 290 K revealed the presence of single-line EPR signals (g(eff) = 2.0044), which were attributed to hydroperoxidic structures produced by the autoxidation process. The photochemical reactions of protoberbenium salts producing reactive oxygen species after UVA excitation should be integrated in biological activity investigations, as well as in their applications in skin disorder treatment.
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Affiliation(s)
- Vlasta Brezová
- Department of Physical Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37 Bratislava, Slovak Republic.
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Mothilal K, Johnson Inbaraj J, Gandhidasan R, Murugesan R. Photosensitization with anthraquinone derivatives: optical and EPR spin trapping studies of photogeneration of reactive oxygen species. J Photochem Photobiol A Chem 2004. [DOI: 10.1016/s1010-6030(03)00290-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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92
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Görner H. Photoreactions of p-benzo-, p-naphtho- and p-anthraquinones with ascorbic acid. Photochem Photobiol Sci 2004; 3:933-8. [PMID: 15480484 DOI: 10.1039/b410386f] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photoreduction of 1,4-benzoquinone (BQ), 1,4-naphthoquinone (NQ), 9,10-anthraquinone (AQ) and several derivatives, e.g. dimethylBQ, trimethylBQ, duroquinone, bromoNQ, methoxyNQ, methylAQ and dimethylAQ in acetonitrile-water by ascorbate was studied by time-resolved UV-vis spectroscopy using 20 ns laser pulses at 308 nm and continuous 254 nm irradiation. The semiquinone radical (*QH/Q*(-)) is formed after H-atom transfer from ascorbate to the quinone triplet state. The rate constant for quenching is k(q)=(2-9) x 10(9) M(-1) s(-1). Termination of the radicals takes place in the micros-ms range. The results are compared with those initiated by electron transfer from DABCO under similar conditions, where the k(q) values are similar, but the termination of Q*(-) takes place by electron back transfer not yielding hydroquinones. Specific properties of the quinone triplet state, e.g. self-quenching, nucleophilic water addition and the effects of structure are discussed.
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Affiliation(s)
- Helmut Görner
- Max-Planck-Institut für Bioanorganische Chemie, D-45413 Mülheim an der Ruhr, Germany
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93
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Gorner H. Photoprocesses of p-naphthoquinones and vitamin K(1): effects of alcohols and amines on the reactivity in solution. Photochem Photobiol Sci 2003; 3:71-8. [PMID: 14743282 DOI: 10.1039/b306670n] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photochemistry of 1,4-naphthoquinone (NQ), the 2-methyl, 2,3-dichloro and 2-bromo derivatives, and vitamin K(1) was studied in non-aqueous solvents by time-resolved UV-vis spectroscopy after ns laser pulses at 248 and 308 nm. The triplet state of the NQs reacts with alcohols and amines, e.g. triethylamine (TEA) and DABCO, yielding semiquinone radicals (HQ(*)/Q (*)(-)). They are the major intermediates and their second-order decay kinetics depend on the properties of the additives and the medium. Transient conductivity measurements suggest the occurrence of photoinduced electron transfer from amines to the triplet state of NQs in acetonitrile. The photoconversion lambda (irr)= 254 nm) of NQs to the 1,4-dihydroxynaphthalenes (H(2)Q) was measured in the absence and presence of varying concentrations of electron and H-atom donors, and the quantum yield was found to increase with increasing electron- or proton-donor concentration. The mechanisms of photoreduction of NQs by propan-2-ol and TEA in acetonitrile exhibit a number of similarities. Oxygen quenches the triplet state, thereby forming singlet molecular oxygen. Oxygen also reacts with the semiquinone radical, thereby forming HO(2)(*)/O(2) (*) (-) radicals, and reacts with H(2)Q, thereby re-forming the quinone. A different pattern, involving intramolecular H-atom transfer, holds for vitamin K(1), where 1,3-quinone methide (1,3-QM) diradicals were observed in acetonitrile prior to formation of two 1,2-QM tautomers, but a triplet was not. The decay of the 1,3-QM intermediates becomes faster in the presence of alcohols and amines due to proton-transfer reactions.
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Affiliation(s)
- Helmut Gorner
- Max-Planck-Institut fur Bioanorganische Chemie, D-45413 Mulheim an der Ruhr, Germany
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Horiuchi H, Ishibashi S, Tobita S, Uchida M, Sato M, Toriba KI, Otaguro K, Hiratsuka H. Photodegradation Processes of Cyanine Dyes in the Film State Induced by Singlet Molecular Oxygen. J Phys Chem B 2003. [DOI: 10.1021/jp027299n] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hiroaki Horiuchi
- Department of Chemistry, Gunma University, Kiryu, Gunma 376-8515, Japan, and R&D, Taiyo Yuden Co. Ltd., Takasaki, Gunma 370-0024, Japan
| | - Sachiko Ishibashi
- Department of Chemistry, Gunma University, Kiryu, Gunma 376-8515, Japan, and R&D, Taiyo Yuden Co. Ltd., Takasaki, Gunma 370-0024, Japan
| | - Seiji Tobita
- Department of Chemistry, Gunma University, Kiryu, Gunma 376-8515, Japan, and R&D, Taiyo Yuden Co. Ltd., Takasaki, Gunma 370-0024, Japan
| | - Mamoru Uchida
- Department of Chemistry, Gunma University, Kiryu, Gunma 376-8515, Japan, and R&D, Taiyo Yuden Co. Ltd., Takasaki, Gunma 370-0024, Japan
| | - Masanori Sato
- Department of Chemistry, Gunma University, Kiryu, Gunma 376-8515, Japan, and R&D, Taiyo Yuden Co. Ltd., Takasaki, Gunma 370-0024, Japan
| | - Ken-ichi Toriba
- Department of Chemistry, Gunma University, Kiryu, Gunma 376-8515, Japan, and R&D, Taiyo Yuden Co. Ltd., Takasaki, Gunma 370-0024, Japan
| | - Kunihiko Otaguro
- Department of Chemistry, Gunma University, Kiryu, Gunma 376-8515, Japan, and R&D, Taiyo Yuden Co. Ltd., Takasaki, Gunma 370-0024, Japan
| | - Hiroshi Hiratsuka
- Department of Chemistry, Gunma University, Kiryu, Gunma 376-8515, Japan, and R&D, Taiyo Yuden Co. Ltd., Takasaki, Gunma 370-0024, Japan
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Görner H. Photoreduction of 9,10-anthraquinone derivatives: transient spectroscopy and effects of alcohols and amines on reactivity in solution. Photochem Photobiol 2003; 77:171-9. [PMID: 12785056 DOI: 10.1562/0031-8655(2003)077<0171:poadts>2.0.co;2] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The photoreduction of 9,10-anthraquinone (AQ), the 2-methyl, 2-ethyl, 2,3-dimethyl, 1,4-difluoro, 1-chloro and 1,8-dichloro derivatives as well as 1,4,4a,9a-tetrahydroanthraquinone, 1,2-benzanthraquinone and 6,13-pentacenequinone in nonaqueous solution at room temperature was studied by time-resolved UV-visible spectroscopy. Upon 308 nm excitation of AQ the triplet state reacts with alcohols and triethylamine (TEA). The rate constant of triplet quenching by amines is close to the diffusion-controlled limit. The semiquinone radical *QH/ Q*- is the main intermediate, and the half-life of the second-order decay kinetics depends significantly on the donor and the medium. Photoinduced charge separation after electron transfer from amines to the triplet state of AQ in acetonitrile and the subsequent charge recombination or neutralization also were measured by transient conductivity. The maximum quantum yield, lambdairr = 254 nm, of photoconversion into the strongly fluorescing 9,10-dihydroxyanthracenes is close to unity. The fluorescence with maximum at 460-480 nm and a lifetime of 20-30 ns disappears as a result of a complete recovery into AQ, when the dihydroxyanthracenes are exposed to oxygen. The mechanisms of photoreduction of parent AQ in acetonitrile by 2-propanol and in benzene and acetonitrile by TEA are discussed. The effects of AQ follow essentially the same pattern. The various functions of oxygen, e.g. (1) quenching of the triplet state; (2) quenching of the semiquinone radical, thereby forming HO2*/O2*- radicals; and (3) trapping of the dihydroxyanthracenes are outlined.
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Affiliation(s)
- Helmut Görner
- Max-Planck-Institut für Strahlenchemie, D-45413 Mülheim an der Ruhr, Germany.
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96
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Görner H. Photoreduction of 9,10-Anthraquinone Derivatives: Transient Spectroscopy and Effects of Alcohols and Amines on Reactivity in Solution¶. Photochem Photobiol 2003. [DOI: 10.1562/0031-8655(2003)077%3c0171:poadts%3e2.0.co;2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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97
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Görner H. Photoreduction of p-Benzoquinones: Effects of Alcohols and Amines on the Intermediates and Reactivities in Solution¶. Photochem Photobiol 2003; 78:440-8. [PMID: 14653574 DOI: 10.1562/0031-8655(2003)078<0440:popeoa>2.0.co;2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The photochemistry of 1,4-benzoquinone (BQ) and alkyl-, Cl- and related derivatives, e.g. methyl-, 2,6-dimethyl-, chloro-, 2,5-dichloro-1,4-benzoquinone, duroquinone and chloranil, was studied in nonaqueous solvents by UV-vis spectroscopy using nanosecond laser pulses at 308 nm. The reactivity of the triplet state (3Q*) of the quinones with 2-propanol in the absence of water is largest for BQ and depends mainly on the quinone structure, whereas the rate constant of electron transfer from amines, such as triethylamine (TEA) or 1,4-diazabicyclo[2.2.2]octane, is close to the diffusion-controlled limit for BQ and most derivatives. Photoinduced charge separation after electron transfer from amines to 3Q* and the subsequent charge recombination or neutralization are supported by time-resolved conductivity measurements. The half-life of the decay kinetics of the semiquinone radical (*QH/Q*-) depends significantly on the donor and the medium. The photoconversion into the hydroquinones was measured under various conditions, the quantum yield, lambda(irr) = 254 nm, increases with increasing 2-propanol and TEA concentrations. The effects of quenching of 3Q*, the *QH/Q*- radicals and the photoconversion are outlined. The mechanisms of photoreduction of quinones in acetonitrile by 2-propanol are compared with those by TEA in benzene and acetonitrile, and the specific properties of substitution are discussed.
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Affiliation(s)
- Helmut Görner
- Max-Planck-Institut für Bioanorganische Chemie, Mülheim an der Ruhr, Germany.
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98
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Dong S, Fu PP, Shirsat RN, Hwang HM, Leszczynski J, Yu H. UVA light-induced DNA cleavage by isomeric methylbenz[a]anthracenes. Chem Res Toxicol 2002; 15:400-7. [PMID: 11896688 DOI: 10.1021/tx015567n] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
UVA light-induced DNA single strand cleavage by a set of 12 monomethyl substituted benz[a]anthracenes (MBAs) along with their parent compound, benz[a]anthracene (BA), and the potent carcinogen, 7,12-dimethylbenz[a]anthracene (DMBA), was studied. On the basis of the relative DNA single strand photocleavage efficiency of the fourteen compounds, they are divided into three groups: (1) strong DNA cleavers, 4-MBA, 5-MBA, 6-MBA, 8-MBA, 9-MBA, 10-MBA, and BA; (2) medium DNA cleavers, 1-MBA, 2-MBA, 3-MBA, and 11-MBA; and (3) weak DNA cleavers, 7-MBA, 12-MBA, and DMBA. The relative DNA photocleavage efficiency parallels very well with the energy gap between the highest-occupied-molecular-orbital (HOMO) and the lowest-unoccupied-molecular-orbital (LUMO) of each MBA, indicating that the DNA cleavage is related to their excited-state properties. The 7 and 12 positions of BA are two unique sites. Methyl substitution at either 7 or 12 (or both) positions lowers the HOMO-LUMO gap and greatly diminishes the DNA photocleavage efficiency. UVA light-induced photodegradation of selected MBAs reveals that methyl substitution at either 7 or 12 (or both) positions greatly enhances the degradation rate. Photodegradation of 7-MBA, 12-MBA, and DMBA yields products that are much less effective in mediating DNA cleavage. Photodegradation of other MBAs, exemplified by 5-MBA, yields a photooxidation product 5-MBA-7,12-quinone which is relatively stable under light and is a stronger DNA photocleaver than 5-MBA itself. The higher efficiency of DNA photocleavage for MBAs with methyl substitution at positions other than 7 or 12 is due, at least in part, to the formation of 7,12-quinone. Light-induced DNA single strand cleavage efficiency for several MBAs parallels the light-induced toxicity observed by other research groups, suggesting that light-induced DNA cleavage of MBAs are the source for phototoxicity. Since some PAHs such as coal tar are used commercially as creams, therapeutic agents, or ointments, or those roofers and asphalt workers that are subject to contamination with PAHs, the combination of PAHs and light (in the skin) may present a greater health risk to humans.
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Affiliation(s)
- Shiming Dong
- Department of Chemistry, Jackson State University, Jackson, Mississippi 39217, USA
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Johnson TW, Zybailov B, Jones AD, Bittl R, Zech S, Stehlik D, Golbeck JH, Chitnis PR. Recruitment of a foreign quinone into the A1 site of photosystem I. In vivo replacement of plastoquinone-9 by media-supplemented naphthoquinones in phylloquinone biosynthetic pathway mutants of Synechocystis sp. PCC 6803. J Biol Chem 2001; 276:39512-21. [PMID: 11470786 DOI: 10.1074/jbc.m104040200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interruption of the phylloquinone (PhQ) biosynthetic pathway by interposon mutagenesis of the menA and menB genes in Synechocystis sp. PCC 6803 results in plastoquinone-9 (PQ-9) occupying the A(1) site and functioning in electron transfer from A(0) to the FeS clusters in photosystem (PS) I (Johnson, T. W., Shen, G., Zybailov, B., Kolling, D., Reategui, R., Beauparlant, S., Vassiliev, I. R., Bryant, D. A., Jones, A. D., Golbeck, J. H., and Chitnis, P. R. (2000) J. Biol. Chem. 275, 8523-8530. We report here the isolation of menB26, a strain of the menB mutant that grows in high light by virtue of a higher PS I to PS II ratio. PhQ can be reincorporated into the A(1) site of the menB26 mutant strain by supplementing the growth medium with authentic PhQ. The reincorporation of PhQ also occurs in cells that have been treated with protein synthesis inhibitors, consistent with a displacement of PQ-9 from the A(1) site by mass action. The doubling time of the menB26 mutant cells, but not the menA mutant cells, approaches the wild type when the growth medium is supplemented with naphthoquinone (NQ) derivatives such as 2-CO(2)H-1,4-NQ and 2-CH(3)-1,4-NQ. Since PhQ replaces PQ-9 in the supplemented menB26 mutant cells, but not in the menA mutant cells, the phytyl tail accompanies the incorporation of these quinones into the A(1) site. Studies with menB26 mutant cells and perdeuterated 2-CH(3)-1,4-NQ shows that phytylation occurs at position 3 of the NQ ring because the deuterated 2-methyl group remains intact. Therefore, the specificity of the phytyltransferase enzyme is selective with respect to the group present at ring positions 2 and 3. Supplementing the growth medium of menB26 mutant cells with 1,4-NQ also leads to its incorporation into the A(1) site, but typically without either the phytyl tail or the methyl group. These findings open the possibility of biologically incorporating novel quinones into the A(1) site by supplementing the growth medium of menB26 mutant cells.
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Affiliation(s)
- T W Johnson
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
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