Carbene-Based Lewis Pairs for Hydrogen Activation

Runyon, Jason W.; Steinhof, Oliver; Dias, H. V. Rasika; Calabrese, Joseph C.; Marshall, William J.; Arduengo, Anthony J.

doi:10.1071/ch11246

Cited by 58 publications

(45 citation statements)

References 11 publications

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“…The cyclic nature of NHCs also helps to favour the singlet state by forcing the carbene carbon into a bent, more sp 2 -like arrangement. This ground-state structure is reflected in the C 2 2N bond lengths (1.37 Å ) observed in IAd, which fall in between those of its corresponding imidazolium salt (IAdH 1 , 1.33 Å ) 4 and its C 2 -saturated analogue (IAdH 2 , 1.49 Å ) 10 , signifying that the C 2 2nitrogen bonds possess partial doublebond character.…”

Section: Structure and General Properties Of Nhcsmentioning

confidence: 93%

An overview of N-heterocyclic carbenes

Hopkinson

Richter

Schedler

et al. 2014

Nature

3,552

1,907

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The successful isolation and characterization of an N-heterocyclic carbene in 1991 opened up a new class of organic compounds for investigation. From these beginnings as academic curiosities, N-heterocyclic carbenes today rank among the most powerful tools in organic chemistry, with numerous applications in commercially important processes. Here we provide a concise overview of N-heterocyclic carbenes in modern chemistry, summarizing their general properties and uses and highlighting how these features are being exploited in a selection of pioneering recent studies.

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Section: Structure and General Properties Of Nhcsmentioning

confidence: 93%

An overview of N-heterocyclic carbenes

Hopkinson

Richter

Schedler

et al. 2014

Nature

3,552

1,907

View full text Add to dashboard Cite

show abstract

“…The signals observed by NMR does not correspond exactly to the initial complex (L 2 -AuCl) and could be attributed neither to the imidazolium salt, nor to the imidazoline (aminal). 40 Additional NMR and mass spectroscopy experiments were also inconclusive. Langmuir 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 …”

Section: Nature Of Ag and Au Organometallic Species Formed In The Prementioning

confidence: 96%

Nanocrystals: Why Do Silver and Gold N-Heterocyclic Carbene Precursors Behave Differently?

et al. 2013

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Synthesizing stable Au and Ag nanocrystals of narrow size distribution from metal-N-heterocyclic carbene (NHC) complexes remains a challenge, particularly in the case of Ag and when NHC ligands with no surfactant-like properties are used. The formation of nanocrystals by one-phase reduction of metal-NHCs (metal = Au, Ag) bearing common NHC ligands, namely 1,3-diethylbenzimidazol-2-ylidene (L(1)), 1,3-bis(mesityl)imidazol-2-ylidene (L(2)), and 1,3-bis(2,6-(i)Pr2C6H3)imidazol-2-ylidene (L(3)), is presented herein. We show that both Au and Ag nanocrystals displaying narrow size distribution can be formed by reduction with amine-boranes. The efficiency of the process and the average size and size distribution of the nanocrystals markedly depend on the nature of the metal and NHC ligand, on the sequence in the reactant addition (i.e., presence or absence of thiol during the reduction step), and on the presence or absence of oxygen. Dodecanethiol was introduced to produce stable nanocrystals associated with narrow size distributions. A specific reaction is observed with Ag-NHCs in the presence of thiols whereas Au-NHCs remain unchanged. Therefore, different organometallic species are involved in the reduction step to produce the seeds. This can be correlated to the lack of effect of NHCs on Ag nanocrystal size. In contrast, alteration of Au nanocrystal average size can be achieved with a NHC ligand of great steric bulk (L(3)). This demonstrates that a well-defined route for a given metal cannot be extended to another metal.

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“…At À60 C this combination was shown to activate H 2 , generating the imidazolium tetrafluoroborate salt and triphenylmethane (Scheme 22, bottom) [75].…”

Section: Alternative Lewis Acids and Bases: Carbonmentioning

confidence: 98%

Non-conventional Lewis Acids and Bases in Frustrated Lewis Pair Chemistry

Caputo

Stephan

2015

The Chemical Bond III

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The discovery of frustrated Lewis pairs (FLPs) was based on the reactions of combinations of sterically demanding phosphine donors and electrophilic boranes with dihydrogen. Since these early findings, the range of species that exhibit FLP chemistry has broadened dramatically to include a series of Lewis acids and bases. In this review, we describe a variety of such systems and the corresponding reactivity of FLPs derived from group 13-16 species.

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Carbene-Based Lewis Pairs for Hydrogen Activation

Cited by 58 publications

References 11 publications

An overview of N-heterocyclic carbenes

An overview of N-heterocyclic carbenes

Nanocrystals: Why Do Silver and Gold N-Heterocyclic Carbene Precursors Behave Differently?

Non-conventional Lewis Acids and Bases in Frustrated Lewis Pair Chemistry

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