A sterically demanding nucleophilic carbene: 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene). Thermochemistry and catalytic application in olefin metathesis

Jafarpour, Laleh; Stevens, Edwin D.; Nolan, Steven P.

doi:10.1016/s0022-328x(00)00260-6

Cited by 311 publications

(212 citation statements)

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“…Solvents were dried by standard methods and freshly distilled prior to use. The compounds 2-bromo-1,3-diethyl-1,3,2-benzodiazaborole (1), 16 4-dimesitylborylphenylacetylene (2), 30 4-cyanophenylacetylene (4), 31 (2-trimethylsilylethynyl)thiophene (8), 32 dimesityl fluoroborane (9) 33 and 1,3-bis(2´,6´-diisopropylphenyl)imidazolium chloride 34 were prepared according to literature methods. 4-Bromobenzonitrile (6), 2-bromoaniline, pphenylenediamine, boron tribromide, sodium tetrahydridoborate, palladium acetate and tetrabutylammonium fluoride trihydrate (TBAF·3H 2 O) were purchased commercially.…”

Section: Methodsmentioning

confidence: 99%

Diazaborolyl-boryl push–pull systems with ethynylene–arylene bridges as ‘turn-on’ fluoride sensors

et al. 2012

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. (2012) 'Diazaborolyl-boryl push pull systems with ethynylene arylene bridges as`turn-on' uoride sensors. ', Dalton transactions., 41 (34). pp. 10328-10346. Further information on publisher's website:http://dx.doi.org/10.1039/c2dt30438dPublisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. IntroductionConjugated organic molecules and polymers with three-coordinate boron units as building blocks have attracted considerable interest because of their linear and non-linear optical and electronic properties, which make them potentially useful in functional materials. 1 Three-coordinate boron generally behaves as a π-acceptor due to its vacant p-orbital, which stabilizes the LUMO of an adjacent conjugated π-electron system and thus lowers the HOMO-LUMO gap of these molecules. This field of research has been dominated by the use of the dimesitylboryl group (BMes 2 , Mes = 2,4,6-Me 3 C 6 H 2 ), in which the unsaturated boron centre is stabilized towards oxidation and hydrolysis by the steric shielding of the four orthomethyl groups. [2][3][4][5] The BMes 2 group is considered to have an acceptor strength between that of NO 2 -and CN-groups. 6,7 Such electron-deficient compounds are efficient electron-transporting and/or emitting layers in organic light emitting diodes (OLEDs). 5 Compounds with BMes 2 groups are often strongly coloured and/or luminescent, 8 which renders them useful as colorimetric or luminescent sensors for fluoride ions. [9][10][11][12][13]

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Section: Methodsmentioning

confidence: 99%

Diazaborolyl-boryl push–pull systems with ethynylene–arylene bridges as ‘turn-on’ fluoride sensors

et al. 2012

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“…Solvents were dried by standard methods and freshly distilled prior to use. The starting materials, H 2 Si(OTf) 2 [22], H 3 Si(OTf) [26] and NHC [27] were prepared according to literature procedures. H 2 SiCl 2 (ABCR) was commercially available and used as received.…”

Section: General Considerationsmentioning

confidence: 99%

Coordination of N-Heterocyclic Carbene to H₂SiX₂ (X = Cl, OTf) and H₃SiOTf (OTf = OSO₂CF₃): Synthesis of Donor-stabilized Parent Silylium Salts with Four- and Five-coordinate Silicon Atoms

Xiong

Yao

Drieß

2013

Zeitschrift Für Naturforschung B

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The reactivity of the N-heterocyclic carbene (NHC) 1,3-bis (2,6-diisopropylphenyl) (5); the latter represent the first NHC adducts of the parent silylium cation (H 3 Si + ). The multinuclear NMR and IR spectroscopic data of the products reflect the characteristics of four-, five-, and six-coordinate silane complexes. All new compounds were structurally characterized by single-crystal X-ray diffraction analyses.

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“…An important role on the catalytic activity is also played by the bulkiness of N-aryl substituents, as generally reported for Ru complex, even with backbone unsubstituted NHCs [41][42][43][44][45]. Phosphine-containing Ru catalysts bearing N-o-isopropylphenyl groups in place of N-o-tolyl (8-synGII and 8-antiGII, Figure 6) can be prepared in good yields (60%-65%) with the same procedures adopted for 7-synGII and 7-antiGII [27].…”

Section: -Gii Antimentioning

confidence: 71%

“…Figure 6) can be prepared in good yields (60%-65%) with the same procedures adopted for 7-synGII and 7-antiGII [27]. As expected by the increased catalyst bulkiness, 8-synGII and 8-antiGII exhibited higher activity in the RCM of substrates 1 and 9 [41][42][43][44][45] with respect to the corresponding o-tolyl N-substituted catalysts (Tables 1 and 2), whereas the RCM of the more encumbered 11 appeared slowed down (Table 3). The increase of catalyst bulkiness was counterproductive also in the ROMP of 13 (Scheme 2), where 8-antiGII gave lower conversion to polymer (8%) with respect to its analogous with N-o-tolyl groups, 7-antiGII (44%) [40].…”

Section: -Gii Antimentioning

confidence: 78%

NHC Backbone Configuration in Ruthenium-Catalyzed Olefin Metathesis

2016

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Abstract:The catalytic properties of olefin metathesis ruthenium complexes bearing N-heterocyclic carbene ligands with stereogenic centers on the backbone are described. Differences in catalytic behavior depending on the backbone configurations of symmetrical and unsymmetrical NHCs are discussed. In addition, an overview on asymmetric olefin metathesis promoted by chiral catalysts bearing C 2 -symmetric and C 1 -symmetric NHCs is provided.

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A sterically demanding nucleophilic carbene: 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene). Thermochemistry and catalytic application in olefin metathesis

Cited by 311 publications

References 28 publications

Diazaborolyl-boryl push–pull systems with ethynylene–arylene bridges as ‘turn-on’ fluoride sensors

Diazaborolyl-boryl push–pull systems with ethynylene–arylene bridges as ‘turn-on’ fluoride sensors

Coordination of N-Heterocyclic Carbene to H₂SiX₂ (X = Cl, OTf) and H₃SiOTf (OTf = OSO₂CF₃): Synthesis of Donor-stabilized Parent Silylium Salts with Four- and Five-coordinate Silicon Atoms

NHC Backbone Configuration in Ruthenium-Catalyzed Olefin Metathesis

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A sterically demanding nucleophilic carbene: 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene). Thermochemistry and catalytic application in olefin metathesis

Cited by 311 publications

References 28 publications

Diazaborolyl-boryl push–pull systems with ethynylene–arylene bridges as ‘turn-on’ fluoride sensors

Diazaborolyl-boryl push–pull systems with ethynylene–arylene bridges as ‘turn-on’ fluoride sensors

Coordination of N-Heterocyclic Carbene to H2SiX2 (X = Cl, OTf) and H3SiOTf (OTf = OSO2CF3): Synthesis of Donor-stabilized Parent Silylium Salts with Four- and Five-coordinate Silicon Atoms

NHC Backbone Configuration in Ruthenium-Catalyzed Olefin Metathesis

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Coordination of N-Heterocyclic Carbene to H₂SiX₂ (X = Cl, OTf) and H₃SiOTf (OTf = OSO₂CF₃): Synthesis of Donor-stabilized Parent Silylium Salts with Four- and Five-coordinate Silicon Atoms