Nonradiative and radiative deactivation of singlet molecular oxygen (O2(a1Δg)) in micellar media and microemulsions

Martínez, Luis A.; Martı́nez, Claudia G.; Klopotek, B. B.; Lang, Josef; Neuner, Annette; Braun, André M.; Oliveros, Esther

doi:10.1016/s1011-1344(00)00109-3

Cited by 54 publications

(65 citation statements)

References 53 publications

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“…The presence of methanol and particularly of water can be responsible for the lower 1 O 2 lifetimes observed in our samples. In fact, t D values in these solvents are among the shortest ones (approximately 4 and 12 ms in water and ethanol, respectively [3,10,11] ), shorter than in our monoliths. Wetzler et al [23] quantified the generation of 1 O 2 by photosensitization using methylene blue (MB) supported on Nafion-Na films by TRPD.…”

Section: Pn-sgmaxmentioning

confidence: 73%

“…The most commonly used method to obtain these values was well described by S. Nonell et al [20] The main features of the time-resolved set-up used in this work for 1 O 2 phosphorescence detection (TRPD) [11] is briefly described below. A Nd-YAG laser [Continuum Surelite II)] equipped with a a frequency tripler (355 nm) was used to irradiate the monoliths.…”

Section: Methodsmentioning

confidence: 99%

“…Many studies provide evidence of 1 O 2 photosensitized generation in a large variety of solvents, [9] as well as in microheterogeneous systems. [10,11] It is important to note that the 1 O 2 lifetime varies considerably depending on its environment [12][13][14] and that the nature of the media may also affect the quantum yields of 1 O 2 production. [15] While the determination of the quantum yields of 1 O 2 production (F D ) is well established in homogeneous systems (usually using a well-known sensitizer as a reference), few studies have dealt with this determination in heterogeneous systems (liquid/solid, gas/solid).…”

Section: Introductionmentioning

confidence: 99%

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Singlet Oxygen in Microporous Silica Xerogel: Quantum Yield and Oxidation at the Gas–Solid Interface

et al. 2007

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The quantum yields of singlet oxygen ((1)O(2)) production (Phi(Delta)) and (1)O(2) lifetimes (tau(Delta)) at the gas-solid interface in silica gel material are determined. Different photosensitizers (PS) are encapsulated in parallelepipedic xerogel monoliths (PS-SG). PS were chosen according to their known photooxidation properties: 9,10-dicyanoanthracene (DCA), 9,10-anthraquinone (ANT), and a benzophenone derivative, 4-benzoyl benzoic acid (4BB). These experiments are mainly based on time-resolved (1)O(2) phosphorescence detection, and the obtained Phi(Delta) and tau(Delta) values are compared with those of a reference sensitizer for (1)O(2) production, 1H-phenalen-1-one (PN), included in the same xerogel. The trend between their ability to oxidize organic pollutants in the gas phase and their efficiency for (1)O(2) production is investigated through photooxidation experiments of a test pollutant dimethylsulfide (DMS). The Phi(Delta) value is high for DCA-SG relative to the PN reference, whereas it is slightly lower for 4BB-SG and for ANT-SG. Phi(Delta) is related to the production of sulfoxide and sulfone as the main oxidation products for DMS photosensitized oxidation. Additional mechanisms, leading to C--S bond cleaveage, appear to mainly occur for the less efficient singlet oxygen sensitizers 4BB-SG and ANT-SG.

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Section: Pn-sgmaxmentioning

confidence: 73%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Singlet Oxygen in Microporous Silica Xerogel: Quantum Yield and Oxidation at the Gas–Solid Interface

et al. 2007

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“…The efficiency of the energy transfer processes could be enhanced by the DPA ligand because of the antenna effect and intramolecular energy transfer in the coordinate complex. CL intensity could be improved by SDBS micelles via improving the intermolecular energy transfer efficiencies, reducing the water quenching effect and prolonging the singlet oxygen lifetime …”

Section: Resultsmentioning

confidence: 99%

Fast determination of peroxymonosulfate by flow injection chemiluminescence using the Tb(III) ligand in micelle medium

et al. 2019

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Based on the chemiluminescence (CL) phenomenon of peroxymonosulfate (PMS) and Tb(III) enhanced by its ligand in a micelle microenvironment, a fast and sensitive flow injection CL method for PMS detection was proposed and applied to the analysis of different samples and PMS decomposition. Under the optimized conditions, a linear range was obtained from 4.0 × 10–6 mol L–1 to 2.0 × 10–4 mol L–1 with a high correlation coefficient (r = 0.9997), detection limit of 5.0 × 10–7 mol L–1 (S/N = 3) and relative standard deviation of 2.4% for 1.0 × 10–5 mol L–1 PMS (n = 9). This was successfully applied to the determination of PMS in Virkon powder, tap water, and swimming pool water samples with satisfactory recoveries from 94.8% to 104.8%. In particular, the analytical frequency could be as fast as five samples per minute because there was no reaction step before analysis and the CL phenomenon was instantaneous. Therefore, this CL method has also been successfully applied to investigate the PMS decomposition profiles in carbon material (carbon nanotubes, carbon nanofibres, activated carbon and graphene oxide) catalysis systems, which followed pseudo‐first‐order kinetics with good correlation coefficients (r > 0.9305). Quenching experiments and electron spin resonance spectra verified that the CL phenomenon was due to the formation of singlet oxygen, and that hydroxyl and sulfate radicals might be important in the generation of singlet oxygen. Tb(III) is the luminescent emitter according to the characteristics emission bands of the fluorescence and CL spectra in different media.

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“…Earlier studies have shown the schematic representations for W/O, O/W and bicontinuous microemulsions [21,23]. Unlike micelles, microemulsions have the advantage of the ability to dissolve large amounts of hydrophobic substances and to accommodate long molecules due to the presence of the oil and cofactor [24].…”

Section: Introductionmentioning

confidence: 99%

Peroxyl radical reactions with carotenoids in microemulsions: Influence of microemulsion composition and the nature of peroxyl radical precursor

El‐Agamey

McGarvey

2016

Free Radical Biology and Medicine

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Cite this article as: Ali El-Agamey and David J. Mcgarvey, Peroxyl radical reactions with carotenoids in microemulsions: Influence of microemulsion composition and the nature of peroxyl radical precursor, Free Radical Biology and Medicine, http://dx.doi.org/10.1016/j.freeradbiomed. 2015.10.427 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThe reactions of acetylperoxyl radicals with different carotenoids (7,7'-dihydro-β-carotene and ζ-carotene) in SDS and CTAC microemulsions of different compositions were investigated using laser flash photolysis (LFP) coupled with kinetic absorption spectroscopy. The primary objective of this study was to explore the influence of microemulsion composition and the type of surfactant used on the yields and kinetics of various transients formed from the reaction of acetylperoxyl radicals with carotenoids. Also, the influence of the site (hydrocarbon phases or aqueous phase) of generation of the peroxyl radical precursor was examined by using 4-acetyl-4-phenylpiperidine hydrochloride

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Nonradiative and radiative deactivation of singlet molecular oxygen (O2(a1Δg)) in micellar media and microemulsions

Cited by 54 publications

References 53 publications

Singlet Oxygen in Microporous Silica Xerogel: Quantum Yield and Oxidation at the Gas–Solid Interface

Singlet Oxygen in Microporous Silica Xerogel: Quantum Yield and Oxidation at the Gas–Solid Interface

Fast determination of peroxymonosulfate by flow injection chemiluminescence using the Tb(III) ligand in micelle medium

Peroxyl radical reactions with carotenoids in microemulsions: Influence of microemulsion composition and the nature of peroxyl radical precursor

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