Aerobic Oxidative Coupling of Amines by Carbon Nitride Photocatalysis with Visible Light

Su, Fangzheng; Mathew, Smitha C.; Möhlmann, Lennart; Antonietti, Markus; Wang, Xinchen; Blechert, Siegfried

doi:10.1002/ange.201004365

Cited by 201 publications

(109 citation statements)

References 32 publications

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“…[5] Recent discoveries demonstrated that surface modification of TiO 2 with noble-metal complexes or nanoparticles rather than bulk doping might be a better strategy in the pursuit of new visible-light-responsive photocatalysts that could prompt the design of efficient redox reactions under visible-light irradiation. In particular, ruthenium-containing dyes [6] and gold nanoparticles [7] supported on TiO 2 have been successfully used for the reduction of nitrobenzene and the oxidation of alcohols under visible-light irradiation.…”

Section: Introductionmentioning

confidence: 99%

Visible‐Light‐Induced Selective Photocatalytic Aerobic Oxidation of Amines into Imines on TiO₂

Lang

Zhao

et al. 2012

Chemistry A European J

187

115

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Imines are important intermediates for the synthesis of fine chemicals, pharmaceuticals, and agricultural chemicals. Selective oxidation of amines into their corresponding imines with dioxygen is one of the most-fundamental chemical transformations. Herein, we report the oxidation of a series of benzylic amines into their corresponding imines with atmospheric dioxygen as the oxidant on a surface of anatase TiO(2) under visible-light irradiation (λ>420 nm). The visible-light response of this system was caused by the formation of a surface complex through the adsorption of a benzylic amine onto the surface of TiO(2). From the analysis of products of specially designed benzylic amines, we demonstrated that a highly selective oxygenation reaction proceeds via an oxygen-transfer mechanism to afford the corresponding carbonyl compound, whose further condensation with an amine would generate the final imine product. We found that when primary benzylic amines (13 examples), were chosen as the substrates, moderate to excellent selectivities for the imine products were achieved (ca. 38-94%) in moderate to excellent conversion rates (ca. 44-95%). When secondary benzylic amines (15 examples) were chosen as the substrates, both the corresponding imines and aldehydes were detected as the main products with moderate to high conversion rates (ca. 18-100%) and lower selectivities for the imine products (ca. 14-69%). When tribenzylamine was chosen as the substrate, imine (27%), dibenzylamine (24%), and benzaldehyde products (39%) were obtained in a conversion of 50%. This report can be viewed as a prototypical system for the activation of C-H bonds adjacent to heteroatoms such as N, O, and S atoms, and oxofuctionalization with air or dioxygen as the terminal oxidant under visible-light irradiation using TiO(2) as the photocatalyst.

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Section: Introductionmentioning

confidence: 99%

Visible‐Light‐Induced Selective Photocatalytic Aerobic Oxidation of Amines into Imines on TiO₂

Lang

Zhao

et al. 2012

Chemistry A European J

187

115

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“…The tri-s-triazine ring structure makes the polymer practically inert to chemical attacks (for example, acid, base, oxygen and organic solvents) and provides an appealing electronic structure as well as surface basicity 24 . These properties have already enabled its use for applications in the energy, catalysis and environmental fields, such as water splitting [25][26][27] , oxygen-reduction reactions 28,29 , selective hydrocarbon oxidation 30,31 , carbon dioxide activation 32 and pollutant control 33 . An improvement to these material functions once this earth-abundant organic semiconductor has been fabricated as a hollow nanostructure with controlled dimensions and surface functionalities can be predicted 34,35 .…”

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confidence: 99%

Bioinspired hollow semiconductor nanospheres as photosynthetic nanoparticles

et al. 2012

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natural photosynthesis occurs in the thylakoid membrane where functional proteins and electron carriers are precisely arranged to efficiently convert sunlight into a chemical potential between the two membrane sides, via charge separation and electron transport chains, for use in oxygen generation and Co 2 fixation. These light-harvesting complexes and cofactors have been actively mimicked using dyes, semiconductors and catalytic nanoparticles. However, the photosynthetic scaffold that optimizes both the capture and distribution of light and separates both the oxidative and reductive species has been mimicked much less often, especially using polymer substances. Here we report the synthesis of hollow nanospheres sized in the optical range and made of a robust semiconductor, melon or carbon-nitride polymer. These hollow nanospheres are shown to function as both light-harvesting antennae and nanostructured scaffolds that improve photoredox catalysis, which was determined to have a 7.5% apparent quantum yield via a hydrogen-generation assay.

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“…Exploiting the high energy electrons and different electronic structures of photocatalysts for useful organic reactions has already enabled the development of several useful photocatalytic transformations18192021222324. Current applications of heterogeneous photocatalysts are mainly focused on photo reduction or oxidation reactions induced by photo generated electrons or holes respectively18192021222324252627282930, whilst other catalytic reactions (including Suzuki coupling reaction) stay essentially untouched from light. Merging electron transfer (ET) of photocatalysts to heterogeneous catalysts (e.g.…”

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confidence: 99%

Facilitating room-temperature Suzuki coupling reaction with light: Mott-Schottky photocatalyst for C-C-coupling

Baar

Blechert

et al. 2013

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The Suzuki coupling reaction is one of the most practiced classes of catalytic C-C bond formation. The development of new means of activating molecules and bonds over old catalysts for C-C bond formation is a fundamental objective for chemists. Here, we report the room-temperature C-C bond formation over heterogeneous Pd catalysts by light-mediated catalyst activation. We employ stimulated electron transfer at the metal-semiconductor interface from optically active mesoporous carbon nitride nanorods to Pd nanoparticles. This photocatalytic pathway is highly efficient for coupling aryl halides with various coupling partners with high activity and selectivity under photo irradiation and very mild conditions.

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Aerobic Oxidative Coupling of Amines by Carbon Nitride Photocatalysis with Visible Light

Cited by 201 publications

References 32 publications

Visible‐Light‐Induced Selective Photocatalytic Aerobic Oxidation of Amines into Imines on TiO₂

Visible‐Light‐Induced Selective Photocatalytic Aerobic Oxidation of Amines into Imines on TiO₂

Bioinspired hollow semiconductor nanospheres as photosynthetic nanoparticles

Facilitating room-temperature Suzuki coupling reaction with light: Mott-Schottky photocatalyst for C-C-coupling

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Aerobic Oxidative Coupling of Amines by Carbon Nitride Photocatalysis with Visible Light

Cited by 201 publications

References 32 publications

Visible‐Light‐Induced Selective Photocatalytic Aerobic Oxidation of Amines into Imines on TiO2

Visible‐Light‐Induced Selective Photocatalytic Aerobic Oxidation of Amines into Imines on TiO2

Bioinspired hollow semiconductor nanospheres as photosynthetic nanoparticles

Facilitating room-temperature Suzuki coupling reaction with light: Mott-Schottky photocatalyst for C-C-coupling

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About

Visible‐Light‐Induced Selective Photocatalytic Aerobic Oxidation of Amines into Imines on TiO₂

Visible‐Light‐Induced Selective Photocatalytic Aerobic Oxidation of Amines into Imines on TiO₂