N-Heterocyclic Carbenes

Arduengo, Anthony J.

doi:10.1071/ch11249

Cited by 6 publications

(4 citation statements)

References 26 publications

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“…Since the discovery of “bottleable” 1,3-diadamantyl imidazol-2-ylidene, a representative of nowadays so-called N-heterocyclic carbenes (NHC’s), carbene chemistry has received enormous attention in coordination chemistry, stabilization of highly reactive main group molecules, homogeneous catalysis, and beyond . So far most of the frequently employed (unsaturated) imidazol-2-ylidene typically form metal complexes via the carbene carbon (C 2 position), while the C 4 and C 5 positions remain unsubstituted or bear only alkyl and/or aryl groups (the numbering of elements in the imidazole ring follows the IUPAC recommendation).…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Backbone P-Functionalized Imidazol-2-ylidene Complexes: En Route to Novel Functional Ionic Liquids

et al. 2012

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1-Alkyl-3-methyl-4-diphenylphosphoryl-imidazolium hydrogensulfate (4a,b) (a: R(1) = R(2) = Me; b: R(1) = (i)Pr, R(2) = Me) and 1-alkyl-3-methyl-4,5-bis(diphenylphosphoryl)imidazolium hydrogensulfate (6a,c) (c: R(1) = (n)Bu, R(2) = Me) were obtained selectively and in good yields by oxidative desulfurization of 1-alkyl-3-methyl-4-diphenylphosphino-imidazole-2-thiones (2a,b) and 1-n-butyl-3-methyl-4,5-bis(diphenylphosphoryl)imidazole-2-thione (3c) or 1,3-dimethyl-4-diphenylthiophosphoryl-5-diphenylphosphino-imidazole-2-thione (5a), respectively, with hydrogen peroxide. Synthesis of phosphoryl functionalized imidazol-2-ylidene complexes of group VI metal pentacarbonyls (7a-9a) and (10b-12b) and bis(phosphoryl) functionalized imidazol-2-ylidene complexes of group VI metal pentacarbonyls (13c-15c) and (16a) with low steric demand (methyl, isopropyl, n-butyl) at both N-centers was achieved through deprotonation of imidazolium salts (4a,b) and (6a,c), respectively,-having HSO(4)(-) as a counterion-with potassium tert-butoxide followed by rapid addition of metal pentacarbonyl acetonitrile complexes [M(CO)(5)(CH(3)CN)] (M = Cr, Mo, W). The products were unambiguously characterized by elemental analyses, spectroscopic and spectrometric methods, and in addition, by single-crystal X-ray structure studies in the cases of 4b, 8a, 15c, and 16a; the latter two reveal imidazole ring bond distance alternation in contrast to 8a.

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Section: Introductionmentioning

confidence: 99%

Synthesis of Backbone P-Functionalized Imidazol-2-ylidene Complexes: En Route to Novel Functional Ionic Liquids

et al. 2012

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“…The present chelated bis-NHC-Pd complex catalysts attain both stability and activity in the Suzuki-Miyaura reaction of aryl chlorides. It is also noted that, compared to some palladium complexes of monocarbene ligands, 1,12 the structures of bis-NHC ligands still need modification to further improve the catalytic activity.…”

Section: Catalytic Studiesmentioning

confidence: 99%

“…Various palladiumNHC complex catalysts have been successfully employed in this reaction. 1,12 Herein, we turned our interest to investigate the catalytic activity of the biphenyl-linked cis-chelated bisNHCPd(II) complexes 7a and 7b in the SuzukiMiyaura cross-coupling reactions of aryl chlorides which are more attractive from the view of economic cost, but more challenging due to the less active nature of the carbonchlorine bond. We chose to examine the coupling of 1-chloro-4-methoxybenzene with phenylboronic acid for the survey of the reaction parameters.…”

Section: Catalytic Studiesmentioning

confidence: 99%

“…1 The reactivity and stability of NHCmetal complexes largely rely on the electronic and steric characteristics of the NHC ligands, which can be controlled by modifying the structures of NHC ligands. Among various NHC ligands, chelate bis-NHCs with a biaryl backbone not only yield more stable metal complexes, but also give interesting features that can provide fine-tuning of topological properties such as steric hindrance, bite angles and chirality.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and catalytic activity of cis-chelated palladium(II) complexes of biphenyl-linked bis(imidazolin-2-ylidene)

Luo¹,

Guo²,

Rao³

2010

Arkivoc

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A new type of biaryl-linked bis(imidazolin-2-ylidene) ligand precursor and corresponding cischelated bis-N-heterocyclic carbenePd(II) complexes have been synthesized starting from 6,6-dimethyl-2,2-dinitro-1,1-biphenyl. The catalytic activity of these NHCPd(II) complexes in the SuzukiMiyaura reactions of aryl chlorides has also been investigated affording biaryls in good to excellent yields.

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Investigating intermediates in the CCC–NHC pincer ligand metalation/transmetalation to Rh sequence, an improved stoichiometric synthesis of CCC–NHC pincer Rh complexes

Amoateng

Zamora‐Moreno

Kuchenbeiser

et al. 2022

Journal of Organometallic Chemistry

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N-Heterocyclic Carbenes

Cited by 6 publications

References 26 publications

Synthesis of Backbone P-Functionalized Imidazol-2-ylidene Complexes: En Route to Novel Functional Ionic Liquids

Synthesis of Backbone P-Functionalized Imidazol-2-ylidene Complexes: En Route to Novel Functional Ionic Liquids

Synthesis and catalytic activity of cis-chelated palladium(II) complexes of biphenyl-linked bis(imidazolin-2-ylidene)

Investigating intermediates in the CCC–NHC pincer ligand metalation/transmetalation to Rh sequence, an improved stoichiometric synthesis of CCC–NHC pincer Rh complexes

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