Nickel Carbon π- Bonded Complexes

Chetcuti, Michael J.

doi:10.1016/b978-008046519-7.00078-2

Cited by 4 publications

(3 citation statements)

References 597 publications

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“…It is well-known that nickel forms a complex with alkenes and alkynes, and complex 8 will be the initial intermediate of this reaction. 4 Considering the result of the experiment using deuterated acid for workup and the results obtained by Hoberg et al, 2 it is reasonable to postulate a nickelacycle 9 as the important intermediate in the next step. The mechanistic rationale of this reaction will then become quite similar to that proposed by Dun ˜ach et al, 3 though the regioselectivity is completely different.…”

Section: Discussionmentioning

confidence: 87%

“…It is well-known that nickel forms a complex with alkenes and alkynes, and complex 8 will be the initial intermediate of this reaction . Considering the result of the experiment using deuterated acid for workup and the results obtained by Hoberg et al, it is reasonable to postulate a nickelacycle 9 as the important intermediate in the next step.…”

Section: Discussionmentioning

confidence: 94%

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Nickel-Mediated Regio- and Chemoselective Carboxylation of Alkynes in the Presence of Carbon Dioxide

et al. 1999

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Alkynes are carboxylated in a highly regio- and chemoselective manner in the presence of Ni(cod)2, DBU, and CO2 to give the carboxylated products in good yields. The reaction was carried out under very mild conditions (CO2 1 atm, 0 °C) in the presence of a stoichiometric amount of alkynes, conjugated enynes, or diynes. The high selectivity observed in the reaction would be explained in terms of the stability and the reactivity of the intermediates.

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Section: Discussionmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 94%

Nickel-Mediated Regio- and Chemoselective Carboxylation of Alkynes in the Presence of Carbon Dioxide

et al. 1999

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“…Use of an excess of (allyl)MgCl was, however, required in order to achieve complete transformation ( 31 P NMR monitoring). This is probably due to Ni-catalyzed C−C coupling side reactions of allylic fragments . On the basis of the high 2+3 J PP value of 117 Hz in the 31 P{ 1 H} NMR spectrum of 6 (see above) and by analogy with the structure of the Fe−Pd and Fe−Pt analogues of 6 , it is proposed that the allyl ligand adopts an η 3 coordination mode, resulting in the absence of a SiO bridge between the Fe and Ni centers (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Reactivity of Heterodinuclear Fe−Ni Complexes with a Bridging Alkoxysilyl Ligand. Crystal Structure of [(OC)₃Fe{μ-Si(OMe)₂(OMe)}(μ-dppm)NiMe]

2001

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The new heterobimetallic complex (1) was obtained in 95% yield by reaction of [NiCl2(PPh3)2] in THF with K[Fe{Si(OMe)3}(CO)3(dppm-P)] at −78 °C. The analogous bromo and iodo complexes were also obtained; the latter is, however, less stable and could not be isolated pure. They display the first examples of a bridging alkoxysilyl ligand between Fe and Ni, and the μ2-η2-SiO bridge is also present in the methyl complex (4) and its phenyl analogue 5. The presence of the four-membered rings was confirmed by a crystal structure determination of 4. Treatment of 1 with excess (allyl)MgCl led to the expected bimetallic allyl complex (6). The rapid η3-allyl → η1-allyl → η3-allyl rearrangement is potentially assisted through stabilization of the coordinatively unsaturated Ni center by a SiO→Ni interaction. The bimetallic benzyl derivative 7 was also isolated. Purging a THF or benzene solution of 4 at room temperature with CO yielded after a few seconds the acyl complex (8), which readily decarbonylates. Its reaction with norbornadiene leads to the insertion product, which is thought to exist as an isomeric mixture with terminal or chelating acyl group (11 ⇌ 11‘). When complex 4 was reacted with t BuNC, rapid insertion occurred and further coordination of a terminal t BuNC ligand to Ni led to the iminoacyl complex (12). Complex 1 proved to be a more efficient catalyst (TON = 4100) for the dehydrogenative coupling of Ph3SnH than its mononuclear counterpart [NiCl2(PPh3)2] (TON = 1050). The maximum turnover frequency (TOF) was ca. 9800 h-1.

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Tritopic NHC Precursors: Unusual Nickel Reactivity and Ethylene Insertion into a C(sp³)–H Bond

et al. 2017

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The imidazolium chloride [C3H3N(C3H6NMe2)N{C(Me)(=NDipp)}]Cl (1; Dipp=2,6‐diisopropyl phenyl), a potential precursor to a tritopic NimineCNHCNamine pincer‐type ligand, reacted with [Ni(cod)2] to give the NiI‐NiI complex 2, which contains a rare cod‐derived η3‐allyl‐type bridging ligand. The implied intermediate formation of a nickel hydride through oxidative addition of the imidazolium C−H bond did not occur with the symmetrical imidazolium chloride [C3H3N2{C(Me)(=NDipp)}2]Cl (3). Instead, a Ni−C(sp3) bond was formed, leading to the neutral NimineCHNimine pincer‐type complex Ni[C3H3N2{C(Me)(=NDipp)}2]Cl (4). Theoretical studies showed that this highly unusual feature in nickel NHC chemistry is due to steric constraints induced by the N substituents, which prevent Ni−H bond formation. Remarkably, ethylene inserted into the C(sp3)−H bond of 4 without nickel hydride formation, thus suggesting new pathways for the alkylation of non‐activated C−H bonds.

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Nickel Carbon π- Bonded Complexes

Cited by 4 publications

References 597 publications

Nickel-Mediated Regio- and Chemoselective Carboxylation of Alkynes in the Presence of Carbon Dioxide

Nickel-Mediated Regio- and Chemoselective Carboxylation of Alkynes in the Presence of Carbon Dioxide

Synthesis and Reactivity of Heterodinuclear Fe−Ni Complexes with a Bridging Alkoxysilyl Ligand. Crystal Structure of [(OC)₃Fe{μ-Si(OMe)₂(OMe)}(μ-dppm)NiMe]

Tritopic NHC Precursors: Unusual Nickel Reactivity and Ethylene Insertion into a C(sp³)–H Bond

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Nickel Carbon π- Bonded Complexes

Cited by 4 publications

References 597 publications

Nickel-Mediated Regio- and Chemoselective Carboxylation of Alkynes in the Presence of Carbon Dioxide

Nickel-Mediated Regio- and Chemoselective Carboxylation of Alkynes in the Presence of Carbon Dioxide

Synthesis and Reactivity of Heterodinuclear Fe−Ni Complexes with a Bridging Alkoxysilyl Ligand. Crystal Structure of [(OC)3Fe{μ-Si(OMe)2(OMe)}(μ-dppm)NiMe]

Tritopic NHC Precursors: Unusual Nickel Reactivity and Ethylene Insertion into a C(sp3)–H Bond

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Synthesis and Reactivity of Heterodinuclear Fe−Ni Complexes with a Bridging Alkoxysilyl Ligand. Crystal Structure of [(OC)₃Fe{μ-Si(OMe)₂(OMe)}(μ-dppm)NiMe]

Tritopic NHC Precursors: Unusual Nickel Reactivity and Ethylene Insertion into a C(sp³)–H Bond