A Triplet Carbene Surviving a Week in Solution at Room Temperature

Iwamoto, Eri; Hirai, Katsuyuki; Tomioka, Hideo

doi:10.1021/ja038423z

Cited by 54 publications

(33 citation statements)

References 15 publications

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“…Thorough understanding of the chemical behavior of the radical ions and the related reactive intermediates would, thus, be indispensable in designing and constructing actual artificial photosynthetic systems. Amazingly long lifetimes of reactive intermediates, carbenes, have been reported recently [16]. These reports strongly encourage workers in the field of reactive intermediates to take on the challenge of actively controlling these unstable intermediates, which is one of the most desirable targets to be reached.…”

Section: Control Of Chemical Behavior Of Ion Radicalsmentioning

confidence: 90%

Artificial photosynthesis via two-electron conversion: Photochemical oxygenation sensitized by ruthenium porphyrins with water as both electron and oxygen atom donor

Inoue

Funyu

Shimada

et al. 2005

Pure and Applied Chemistry

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Recent progress in the field of artificial photosynthesis is reviewed. Among various approaches to oxidizing the water molecule, attention has been focused on the two-electron chemical conversion processes mediated by metallo-porphyrins upon visible light irradiation. Photochemical oxygenation reactions such as the epoxidation of alkenes sensitized by ruthenium(II) porphyrins with water as both electron and oxygen atom donor have been found. Ru porphyrin induces highly efficient two-electron oxidation of water with a quantum yield of 60 % to form an epoxide from the alkene with high selectivity. The water molecule serves as both an efficient electron and oxygen atom donor in the reaction, in which the oxygen atom of water is incorporated in a useful product, i.e., epoxide.

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Section: Control Of Chemical Behavior Of Ion Radicalsmentioning

confidence: 90%

Artificial photosynthesis via two-electron conversion: Photochemical oxygenation sensitized by ruthenium porphyrins with water as both electron and oxygen atom donor

Inoue

Funyu

Shimada

et al. 2005

Pure and Applied Chemistry

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“…In contrast to persistent triplet carbenes, 191 which upon appropriate substitution with bulky aryl groups can be stable for a week at room temperature in benzene solution, 192 neither isolable nor persistent triplet silylenes have ever been reported. The unavailability of triplet silylenes can be explained by taking into account the following considerations.…”

Section: Triplet Species: Generation and Identificationmentioning

confidence: 99%

Heavy Analogs of Carbenes: Silylenes, Germylenes, Stannylenes and Plumbylenes

Lee

Sekiguchi

2010

Organometallic Compounds of Low‐Coordinate Si, Ge, Sn and Pb

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The Si-Si bonds of the oligo-or polysilanes chains can be cleaved upon photolysis in two ways, forming either silylenes or silyl radicals. 2 Thus, photolysis of both poly(di-nbutylsilane) and poly(di-n-hexylsilane) with shorter wavelength light [248 nm (pulsed) or 254 nm (CW)] resulted in both extrusion of silylenes R 2 Si • • (R = n-butyl or n-hexyl) trapped with Et 3 SiH and homolytic Si-Si bond cleavage, whereas only polysilyl radicals were observed upon irradiation with longer wavelength light (λ > 300 nm). 3 Among the most frequently used precursors for the photochemical generation of silylenes are trisilanes RR Si(SiMe 3 ) 2 , which readily eliminate hexamethyldisilane Me 3 Si-SiMe 3 to form the corresponding silylenes RR Si • •. Thus, diphenylsilylene Ph 2 Si • • was produced by irradiation of Ph 2 Si(SiMe 3 ) 2 along with the by-products formed from the isomeric silatriene (Scheme 4.1). 4

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“…On the other hand, although triplet carbenes have two unpaired electrons on one carbon atom and have the potential of application as organic magnetic materials, triplet carbenes are much more difficult to stabilize relative to their singlet counterparts. Therefore, the synthesis of isolable triplet carbenes is a worthwhile challenge …”

Section: Introductionmentioning

confidence: 99%

Generation of triplet carbenes by oxidation of an allene compound

Fuku-en

Yamaguchi

Kojima

et al. 2011

J of Physical Organic Chem

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Computational analysis on the dicationic species generated upon two‐electron oxidation of the corresponding allenic compounds bearing two thioxanthene (7a) or two acridene (7b) moieties indicated that the ground‐state multiplicity would be of the triplet state (ΔEST = ECS − ET = 12.6 and 14 kcal/mol, respectively). Under this premise, oxidation reactions of 7a and 7b were carried out. In the case of 7b, oxidation with (p‐BrC6H4)3N•+SbCl6− gave a dimer (13), which could be presumed to have formed by dimerization of the corresponding carbene. Oxidation of 7b in the presence of tetramethylpiperidine N‐oxide afforded the corresponding ketone derivative (14), thus implying the likelihood of a triplet carbene being the reactive intermediate. These results suggest that double oxidation of heterocyclic allene compounds is viable as a new approach for generating triplet carbenes. Copyright © 2011 John Wiley & Sons, Ltd.

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A Triplet Carbene Surviving a Week in Solution at Room Temperature

Cited by 54 publications

References 15 publications

Artificial photosynthesis via two-electron conversion: Photochemical oxygenation sensitized by ruthenium porphyrins with water as both electron and oxygen atom donor

Artificial photosynthesis via two-electron conversion: Photochemical oxygenation sensitized by ruthenium porphyrins with water as both electron and oxygen atom donor

Heavy Analogs of Carbenes: Silylenes, Germylenes, Stannylenes and Plumbylenes

Generation of triplet carbenes by oxidation of an allene compound

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