Anionic N-heterocyclic carbenes: Synthesis, coordination chemistry and applications in homogeneous catalysis

Nasr, Alexandre; Winkler, Andrea; Tamm, Matthias

doi:10.1016/j.ccr.2016.02.011

Cited by 193 publications

(127 citation statements)

References 298 publications

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“…To demonstrate N 2 activation by the individual moieties, we started with the NHCs first. Owing to the development of novel synthetic strategies and versatile applicability, NHCs have gained considerable attention . Based on several studies highlighting reactivity of NHCs, cyclic alkyl amino carbenes (CAACs) proved to be more reactive than that of cyclic diamino carbenes (CDACs), due to the presence of one nitrogen atom and σ‐donating tetravalent carbon that decreases their HOMO‐LUMO gaps with the slightly higher HOMO .…”

Section: Resultsmentioning

confidence: 99%

Dinitrogen Activation by Tricoordinated Boron Species: A Systematic Design

Rouf

Dai

et al. 2020

Advcd Theory and Sims

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Molecular nitrogen (N2), an abundant component of the atmosphere, is appealing for industrial value‐added products. However, its intrinsic inertness limits its activation to mainly metallic species. Environmental concerns and harsh reaction conditions have resulted in a demand for alternate nonmetallic and nontoxic routes to activate and functionalize N2 at ambient conditions. Comprehensive density functional theory (DFT) calculations are performed on N2 activation by boron species, specifically for the experimentally more accessible tricoordinated boron compounds. Subsequently designed frustrated Lewis pairs (FLPs) combining screened N‐heterocyclic carbene with boron moieties can make N2 activation both kinetically and thermodynamically favorable, displaying high potential for metal‐free N2 activation. The significant thermodynamic stability of the products stabilized by aromaticity and low activation barriers could be a breakthrough for the development of FLP chemistry on metal‐free N2 activation.

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Section: Resultsmentioning

confidence: 99%

Dinitrogen Activation by Tricoordinated Boron Species: A Systematic Design

Rouf

Dai

et al. 2020

Advcd Theory and Sims

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“…In recent years, anionic N ‐heterocyclic carbenes have emerged as an important class of novel NHC ligands . Contributions of our group have been based on the consideration that frustrated Lewis pairs, composed of bulky imidazolin‐2‐ylidenes and boranes such as B(C 6 F 5 ) 3 , would form abnormal carbene adducts, in which the weakly coordinating anionic (WCA) borate unit is attached to the 4‐position of the N ‐heterocycle .…”

Section: Introductionmentioning

confidence: 99%

“…In recent years, anionic N-heterocyclicc arbenes have emergeda sa ni mportant class of novel NHC ligands. [36] Contributions of our group have been based on the consideration that frustrated Lewis pairs, composed of bulky imidazolin-2-ylidenes and boranes such as B(C 6 F 5 ) 3 ,w ould form abnormalc arbene adducts,i nw hich the weakly coordinating anionic (WCA) borate unit is attached to the 4-position of the N-heterocycle. [37][38][39][40][41] The corresponding anionic carbenes were termed WCA-NHCsa nd introduced as ancillary ligandsi nt ransition metal complexes and homogeneous catalysts.…”

Section: Introductionmentioning

confidence: 99%

London Dispersion Interactions in Pnictogen Cations [ECl₂]⁺ and [E=E]²⁺ (E=P, As, Sb) Supported by Anionic N‐Heterocyclic Carbenes

Nasr

Jones

et al. 2018

Chemistry A European J

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Several pnictogen dihalide complexes of the type (WCA‐IDipp)EX2 (E=P, As, Sb; X=Cl, Br) that bear an anionic N‐heterocyclic carbene ligand with a weakly coordinating borate moiety (WCA‐IDipp, WCA=B(C6F5)3, IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene) were prepared by salt metathesis reactions between the respective pnictogen trihalides EX3 and the lithium salt (WCA‐IDipp)Li⋅toluene. Two‐electron reduction of the dihalides (WCA‐IDipp)EX2 with 1,3‐bis(trimethylsilyl)‐1,4‐dihydropyrazine or elemental magnesium afforded the dipnictenes (WCA‐IDipp)2E2, which display typical element‐element double bonds as observed in diaryldiphosphenes, ‐arsenes and ‐stibenes. To provide an insight into the factors contributing to the structural stability of the pnictogen dihalide and dipnictene compounds, quantum chemical calculations were performed at the domain‐based local pair natural orbital coupled‐cluster (DLPNO‐CCSD(T)) level. A local energy decomposition (LED) analysis of the interaction between the carbene and the pnictogen dihalide or dipnictene moiety demonstrates that London dispersion is an essential factor for the stabilization of these compounds.

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“…Consequently books [14–16] and reviews cover the range from NHC structures in the light of their early history [17], syntheses [6,18], coordination chemistry [19–20], and catalysis [21–22], to biological activities of NHC complexes [23–24]. In the last decade, attention has also been directed to anionic N-heterocyclic carbenes [25]. In this context, mesomeric betaines are interesting from two viewpoints.…”

Section: Introductionmentioning

confidence: 99%

From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

Liu

Namyslo

Nieger

et al. 2016

Beilstein J. Org. Chem.

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The mesomeric betaine imidazolium-1-ylphenolate forms a borane adduct with tris(pentafluorophenyl)borane by coordination with the phenolate oxygen, whereas its NHC tautomer 1-(2-phenol)imidazol-2-ylidene reacts with (triphenylphosphine)gold(I) chloride to give the cationic NHC complex [Au(NHC)2][Cl] by coordination with the carbene carbon atom. The anionic N-heterocyclic carbene 1-(2-phenolate)imidazol-2-ylidene gives the complexes [K][Au(NHC−)2], [Rh(NHC−)3] and [Ni(NHC−)2], respectively. Results of four single crystal analyses are presented.

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Anionic N-heterocyclic carbenes: Synthesis, coordination chemistry and applications in homogeneous catalysis

Cited by 193 publications

References 298 publications

Dinitrogen Activation by Tricoordinated Boron Species: A Systematic Design

Dinitrogen Activation by Tricoordinated Boron Species: A Systematic Design

London Dispersion Interactions in Pnictogen Cations [ECl₂]⁺ and [E=E]²⁺ (E=P, As, Sb) Supported by Anionic N‐Heterocyclic Carbenes

From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

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Anionic N-heterocyclic carbenes: Synthesis, coordination chemistry and applications in homogeneous catalysis

Cited by 193 publications

References 298 publications

Dinitrogen Activation by Tricoordinated Boron Species: A Systematic Design

Dinitrogen Activation by Tricoordinated Boron Species: A Systematic Design

London Dispersion Interactions in Pnictogen Cations [ECl2]+ and [E=E]2+ (E=P, As, Sb) Supported by Anionic N‐Heterocyclic Carbenes

From betaines to anionic N-heterocyclic carbenes. Borane, gold, rhodium, and nickel complexes starting from an imidazoliumphenolate and its carbene tautomer

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London Dispersion Interactions in Pnictogen Cations [ECl₂]⁺ and [E=E]²⁺ (E=P, As, Sb) Supported by Anionic N‐Heterocyclic Carbenes