Oxidation of an electron-rich olefin induced by singlet oxygen: mechanism for tetraphenylethylene

Machado, Antônio Eduardo da Hora; Andrade, Marcelo Luiz de; Severino, Divinomar

doi:10.1016/1010-6030(95)04116-5

Cited by 9 publications

(3 citation statements)

References 32 publications

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“…Formation of Dioxetanes via Radical Coupling. The radical coupling reaction between the anthracene radical cation and O 2 •- to produce An-O 2 in Scheme can be expanded to the dioxetane formation from olefins. − Visible light irradiation (λ > 430 nm) to an O 2 -saturated MeCN solution of Acr + −Mes (2.0 × 10 -3 M) with tetraphenylethylene or tetramethylethylene (1.0 × 10 -2 M) results in formation of the corresponding radical cation and O 2 •- , followed by the radical coupling to afford the dioxetane as shown in Scheme . The products were analyzed by 1 H NMR (see Experimental Section).…”

Section: Resultsmentioning

confidence: 99%

Photocatalytic Oxygenation of Anthracenes and Olefins with Dioxygen via Selective Radical Coupling Using 9-Mesityl-10-methylacridinium Ion as an Effective Electron-Transfer Photocatalyst

2004

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Visible light irradiation of the absorption band of 9-mesityl-10-methylacridinium ion (Acr+-Mes) in an O2-saturated acetonitrile (MeCN) solution containing 9,10-dimethylanthracene results in formation of oxygenation product, i.e., dimethylepidioxyanthracene (Me2An-O2). Anthracene and 9-methylanthracene also undergo photocatalytic oxygenation with Acr+-Mes to afford the corresponding epidioxyanthracenes under the photoirradiation. In the case of anthracene, the further photoirradiation results in formation of anthraquinone as the final six-electron oxidation product, via 10-hydroxyanthrone, accompanied by generation of H2O2. When anthracene is replaced by olefins (tetraphenylethylene and tetramethylethylene), the photocatalytic oxygenation of olefins affords the corresponding dioxetane, in which the O-O bond is cleaved to yield the corresponding ketones. The photocatalytic oxygenation of anthracenes and olefins is initiated by photoexcitation of Acr+-Mes, which results in formation of the electron-transfer state: Acr*-Mes*+, followed by electron transfer from anthracenes and olefins to the Mes*+ moiety together with electron transfer from the Acr* moiety to O2. The resulting anthracene and olefin radical cations undergo the radical coupling reactions with O2*- to produce the epidioxyanthracene (An-O2) and dioxetane, respectively.

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Section: Resultsmentioning

confidence: 99%

Photocatalytic Oxygenation of Anthracenes and Olefins with Dioxygen via Selective Radical Coupling Using 9-Mesityl-10-methylacridinium Ion as an Effective Electron-Transfer Photocatalyst

2004

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“…In this approach, the reactants are kept apart, allowing for the programmed assembly of heterostructures. The LBL approach has been successfully used for heteroepitaxy, and even lattice-constant mismatches as large as 20% could be overcome. , The availability of such well-defined, crystalline multilayers has allowed us to demonstrate that interesting phenomena occur at such heterointerfaces, including photon excitation and charge carrier transport. , To further explore the potential of MOF-on-MOF heterostructures, we examined photochemically active MOF-on-MOF heterostructures to realize spatial control of photochemical reactions. For this purpose, we designed a heterostructure combining a photosensitizer and a reactant.…”

Section: Introductionmentioning

confidence: 99%

“…27,28 The availability of such well-defined, crystalline multilayers has allowed us to demonstrate that interesting phenomena occur at such heterointerfaces, including photon excitation and charge carrier transport. 29,30 To further explore the potential of MOF-on-MOF heterostructures, we examined photochemically active MOF-on-MOF heterostructures to realize spatial control of photochemical reactions. For this purpose, we designed a heterostructure combining a photosensitizer and a reactant.…”

Section: ■ Introductionmentioning

confidence: 99%

Photoinduced Delamination of Metal–Organic Framework Thin Films by Spatioselective Generation of Reactive Oxygen Species

Liu

Mazel

Marschner

et al. 2021

ACS Appl. Mater. Interfaces

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Metal–organic frameworks (MOFs) built from different building units offer functionalities going far beyond gas storage and separation. In connection with advanced applications, e.g., in optoelectronics, hierarchical MOF-on-MOF structures fabricated using sophisticated methodologies have recently become particularly attractive. Here, we demonstrate that the structural complexity of MOF-based architectures can be further increased by employing highly spatioselective photochemistry. Using a layer-by-layer, quasi-epitaxial synthesis method, we realized a photoactive MOF-on-MOF hetero-bilayer consisting of a porphyrinic bottom layer and a tetraphenylethylene (TPE)-based top layer. Illumination of the monolithic thin film with visible light in the presence of oxygen gas results in the generation of reactive oxygen species (1O2) in the porphyrinic bottom layer, which lead to a photocleavage of the TPE units at the internal interface. We demonstrate that this spatioselective photochemistry can be utilized to delaminate the top layers, yielding two-dimensional (2D) MOF sheets with well-defined thickness. Experiments using atomic force microscopy (AFM) demonstrate that these platelets can be transferred onto other substrates, thus opening up the possibility of fabricating planar MOF structures using photolithography.

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Giant Vesicles under Oxidative Stress Induced by a Membrane-Anchored Photosensitizer

Riske

Sudbrack

Archilha

et al. 2009

Biophysical Journal

128

133

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We have synthesized the amphiphile photosensitizer PE-porph consisting of a porphyrin bound to a lipid headgroup. We studied by optical microscopy the response to light irradiation of giant unilamellar vesicles of mixtures of unsaturated phosphatidylcholine lipids and PE-porph. In this configuration, singlet oxygen is produced at the bilayer surface by the anchored porphyrin. Under irradiation, the PE-porph decorated giant unilamellar vesicles exhibit a rapid increase in surface area with concomitant morphological changes. We quantify the surface area increase of the bilayers as a function of time and photosensitizer molar fraction. We attribute this expansion to hydroperoxide formation by the reaction of the singlet oxygen with the unsaturated bonds. Considering data from numeric simulations of relative area increase per phospholipid oxidized (15%), we measure the efficiency of the oxidative reactions. We conclude that for every 270 singlet oxygen molecules produced by the layer of anchored porphyrins, one eventually reacts to generate a hydroperoxide species. Remarkably, the integrity of the membrane is preserved in the full experimental range explored here, up to a hydroperoxide content of 60%, inducing an 8% relative area expansion.

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Oxidation of an electron-rich olefin induced by singlet oxygen: mechanism for tetraphenylethylene

Cited by 9 publications

References 32 publications

Photocatalytic Oxygenation of Anthracenes and Olefins with Dioxygen via Selective Radical Coupling Using 9-Mesityl-10-methylacridinium Ion as an Effective Electron-Transfer Photocatalyst

Photocatalytic Oxygenation of Anthracenes and Olefins with Dioxygen via Selective Radical Coupling Using 9-Mesityl-10-methylacridinium Ion as an Effective Electron-Transfer Photocatalyst

Photoinduced Delamination of Metal–Organic Framework Thin Films by Spatioselective Generation of Reactive Oxygen Species

Giant Vesicles under Oxidative Stress Induced by a Membrane-Anchored Photosensitizer

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