Rate constants for the decay and reactions of the lowest electronically excited singlet state of molecular oxygen in solution

Wilkinson, Frances; Brummer, J. G.

doi:10.1063/1.555655

Cited by 443 publications

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“…• OH, CO 33 In the case of 3 CDOM*, it is used a pseudo-first order decay constant determined for aerated aqueous systems, 34 which is higher than for anoxic waters due to reaction (4). This choice is due to the fact that the model 40 applies to the surface water layer that is usually well oxygenated.…”

Section: The Photochemical Model For Surface Watersmentioning

confidence: 99%

APEX (Aqueous Photochemistry of Environmentally occurring Xenobiotics): a free software tool to predict the kinetics of photochemical processes in surface waters

Bodrato¹,

Vione

2014

Environ. Sci.: Processes Impacts

122

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Section: The Photochemical Model For Surface Watersmentioning

confidence: 99%

APEX (Aqueous Photochemistry of Environmentally occurring Xenobiotics): a free software tool to predict the kinetics of photochemical processes in surface waters

Bodrato¹,

Vione

2014

Environ. Sci.: Processes Impacts

122

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“…Equation (14) (Wilkinson and Brummer, 1981). Under the adopted experimental conditions, the initial transformation rate of FFA was R FFA = (1.10±0.08)⋅10 −7 M s −1 .…”

Section: Reaction With 1 Omentioning

confidence: 99%

Phototransformation of the sunlight filter benzophenone-3 (2-hydroxy-4-methoxybenzophenone) under conditions relevant to surface waters

Vione

Caringella

Laurentiis

et al. 2013

Science of The Total Environment

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. Phototransformation of the sunlight filter benzophenone-3 (2-hydroxy-4-methoxybenzophenone) under conditions relevant to surface waters. Sci. Total Environ. 2013, 463-464, 243-251. DOI: 10.1016/j.scitotenv.2013 You may download, copy and otherwise use the AAM for non-commercial purposes provided that your license is limited by the following restrictions:(1) You may use this AAM for non-commercial purposes only under the terms of the CC-BY-NC-ND license.(2) The integrity of the work and identification of the author, copyright owner, and publisher must be preserved in any copy. AbstractThe UV filter benzophenone-3 (BP3) has UV photolysis quantum yield s −1 ), the CO 3 −• degradation process could be somewhat important for DOC < 1 mg C L −1 . The predicted half-life time of BP3 in surface waters under summertime conditions would be of some weeks, and it would increase with increasing depth and DOC. BP3 transformation intermediates were detected upon reaction with • OH. Two methylated derivatives were tentatively identified, and they were probably produced by reaction between BP3 and fragments arising from photodegradation. The other intermediates were benzoic acid (maximum concentration ∼10% of initial BP3) and benzaldehyde (1%).

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“…5 Studies in the literature suggest that the photooxidative mechanisms via singlet oxygen are often more efficient than radical processes due to the higher diffusibility of 1 O 2 and the higher reaction rate constants with substrates. 6,7 Nonetheless, other studies show that photooxidations occur largely by a type I mechanism. 8,9 Some researchers have proposed that the type I mechanism is favored in polar solvents since the radicals generated through electron transfer would be stabilized in solvents with a high dielectric constant.…”

Section: Introductionmentioning

confidence: 99%

Type II photooxidation mechanism of biomolecules using chloro (5,10,15,20-Tetraphenylporphyrinato) indium (III) as a photosensitizer

Silva¹,

Ribeiro²,

Rettori³

et al. 2008

J. Braz. Chem. Soc.

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Foi determinado o mecanismo de fotooxidação de albumina de soro bovino (BSA), L-triptofano (Trp) e células vermelhas do sangue (RBC) por cloro (5,10,15,20-tetrafenilporfirinato) de índio(III) (InTPP). A velocidade de fotooxidação de Trp, BSA e RBC por InTPP foi diminuída na presença de NaN 3 . A presença de D 2 O aumentou a velocidade de fotooxidação de Trp e BSA e diminuiu a de RBC. Esta diminuição provavelmente está correlacionada com a redução da constante de associação entre InTPP e RBC na presença de D 2 O. Não foi observada variação significativa na fluorescência das biomoléculas ou sobre a porcentagem de hemólise quando supressores de radicais (ferricianeto, manitol e superóxido dismutase) foram usados. Experimentos usando espectroscopia de ressonância paramagnética (EPR) mostraram que somente o 1 O 2 foi gerado por InTPP. Foi proposto um modelo cinético para a fotooxidação de Trp e BSA. A concordância entre os resultados experimentais e este modelo corrobora a predominância do mecanismo via 1 O 2 na fotooxidação das biomoléculas pelo InTPP.The photooxidation mechanism of bovine serum albumin (BSA), L-tryptophan (Trp) and red blood cells (RBC) by chloro (5,10,15,20-tetraphenylporphyrinato)indium(III) (InTPP) was investigated. The photooxidation rate of Trp, BSA and RBC by InTPP was decreased in the presence of NaN 3 . The presence of D 2 O increases the photooxidation rate of Trp and BSA and decreases that of RBC. This decrease is probably related to a reduction of the binding constant between InTPP and RBC in the presence of D 2 O. No significant change in biomolecule fluorescence or in the percent of hemolysis was observed when radical quenchers (ferricyanide, mannitol and dismutase superoxide) were used. Experiments using electron paramagnetic resonance (EPR) show that only 1 O 2 was generated by InTPP. A mechanistic model based on the preferential oxidation of Trp and BSA by singlet oxygen is proposed. The agreement between the experimental data and the kinetic model gives additional support to the predominance of a mechanism via 1 O 2 in biomolecule photooxidation by InTPP.Keywords: chloro(5,10,15,20-tetraphenylporphyrinato)indium(III), photodynamic therapy, photooxidation mechanism, cancer, erythrocytes IntroductionPhotodynamic therapy (PDT) is a two-step therapeutic modality in which the topical or systemic delivery of photosensitizing drugs is followed by irradiation with visible light, at doses that are not in themselves harmful. 1 For treatment of cancer the photosensitizer is retained preferentially by the tumor and when excited by irradiation generates reactive oxygen species (ROS) that have a cytotoxic effect to the neoplasm. 2 These ROS can be generated by two mechanisms, known as type I and type II. 3,4 In type I the photosensitizer in the excited triplet state can interact directly with the substrate and/or solvent, through an electron transfer reaction or hydrogen transfer, generating radical ions or neutral radicals, which quickly react with oxygen molecules producing ROS such as supero...

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Rate constants for the decay and reactions of the lowest electronically excited singlet state of molecular oxygen in solution

Cited by 443 publications

References 0 publications

APEX (Aqueous Photochemistry of Environmentally occurring Xenobiotics): a free software tool to predict the kinetics of photochemical processes in surface waters

APEX (Aqueous Photochemistry of Environmentally occurring Xenobiotics): a free software tool to predict the kinetics of photochemical processes in surface waters

Phototransformation of the sunlight filter benzophenone-3 (2-hydroxy-4-methoxybenzophenone) under conditions relevant to surface waters

Type II photooxidation mechanism of biomolecules using chloro (5,10,15,20-Tetraphenylporphyrinato) indium (III) as a photosensitizer

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