Complexes with Protic N‐Heterocyclic Carbene (NR,NH‐NHC) Ligands

Hahn, F. Ekkehardt

doi:10.1002/9781118742952.ch9

Cited by 5 publications

(2 citation statements)

References 139 publications

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“…An alternative approach toward NHC complexes is the template synthesis of metal-coordinated isonitriles with suitable amines as nucleophiles. Following this route, cyclic carbene complexes can be obtained either by suitable leaving groups that are attached to an intermoleculary offered nucleophile or by the use of functionalized isonitriles that can undergo ring closure in an intramolecular fashion …”

Section: Introductionmentioning

confidence: 99%

Synthesis of Different Classes of Six-Membered Gold(I) NHC Complexes by the Isonitrile Route

Wurm¹,

Mulks²,

Böhling³

et al. 2016

Organometallics

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Different types of six-membered N-heterocyclic gold carbene complexes were prepared by using gold(I) isonitrile complexes as precursors in combination with suitably functionalized amines. The simple procedures provide an easy access to not only unsymmetrically substituted saturated carbene complexes but rarely reported types of carbene complexes such as six-membered N-heterocyclic oxo-carbene complexes, and six-membered partly unsaturated ligands can be obtained following the strategy.

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Section: Introductionmentioning

confidence: 99%

Synthesis of Different Classes of Six-Membered Gold(I) NHC Complexes by the Isonitrile Route

Wurm¹,

Mulks²,

Böhling³

et al. 2016

Organometallics

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“…Owing to the presence of the acidic N H , pNHCs are not stable as free ligands, in contrast to their corresponding imidazole tautomers; pNHCs cannot generally be obtained by simple deprotonation of the corresponding imidazolium salts . Thus, pNHC complexes have been comparatively less investigated and their synthesis can occasionally be challenging; their coordination chemistry has been recently reviewed . Conversely, the NH moiety in a pNHC complex can act as a reactive site of potential relevance to bifunctional catalysis and substrate recognition. ,, Furthermore, metal complexes with pincer-type ligands are attracting continuing interest, largely driven by their unique photophysical and chemical properties, the latter in particular with respect to catalytic transformations .…”

Section: Introductionmentioning

confidence: 99%

Trifunctional pNHC, Imine, Pyridine Pincer-Type Iridium(III) Complexes: Synthetic, Structural, and Reactivity Studies

Danopoulos

Braunstein

2015

Organometallics

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Iridium(III) complexes with a trifunctional pincer ligand containing protic N-heterocyclic carbene (pNHC), pyridine, and imine donor groups were obtained in two sequential steps: (i) protonation of 2-(1-(2,6-diisopropylphenylimino)ethyl)-6-(1-imidazolyl)pyridine (L CH; the superscript specifies the position of the tautomerizable H atom in the imidazole ring) with HBF4·Et2O to give the imidazolium salt [HL CH]+[BF4]− (protonation always occurs at the imidazole N atom) and (ii) metalation of the latter with [Ir(cod)(μ-Cl)]2 to give the hydrido pincer complex [Ir(H)(Cl)(NCMe){L NH-κ3 N imine,N Py,C NHC}]+[BF4]− (3 +[BF4]−). Substitution of MeCN in 3 +[BF4]− by treatment with triisopropylphosphine gave the analogue [Ir(H)(Cl)P(i-Pr)3{L NH-κ3 N imine,N Py,C NHC}]+[BF4]− (4 +[BF4]−). Chloride abstraction from 3 +[BF4]− by AgBF4 gave [Ir(H)(NCMe)2{L NH-κ3 N imine,N Py,C NHC}]2+[BF4 –]2 (5 2+[BF4 –]2). The centrosymmetric dinuclear Ir(III) complex [Ir(H)(NCMe){μ-(L CH−H)-κ3 N imine,N Py,C2,κN3}]2 2+[B(C6F5)3F–]2 (6 2+[B(C6F5)3F–]2) was obtained after deprotonation of 5 2+[BF4 –]2 with KO-t-Bu, followed by addition of B(C6F5)3. It contains two Ir pincer moieties, each with a Nimine,NPy,C2 donor set, which are connected by the Ir–N bonds involving the imidazolide rings, leading to a μ-C,N bridging mode for the latter. Remarkably, all of the donor atoms in the tetradentate bridging chelating ligands are chemically different. The molecular structures of 3 +[BF4]−·CH2Cl2, 4 +[BF4]−·CH2Cl2, 5 2+[BF4 –]2·2CH2Cl2, and 6 2+[B(C6F5)3F–]2·4CH2Cl2 have been determined by X-ray diffraction.

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From Isonitriles to Unsaturated NHC Complexes of Gold, Palladium and Platinum

et al. 2015

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In am odular template synthesis,unsaturated NHC complexes of gold, palladium andp latinum were synthesizedf rom simplem etal salts,i sonitriles and aminesw ith acetal or ketal groups.U pon the addition of aminesw ith tethereda cetal or ketal moieties to the metal-activated isonitrile,f irst nitrogen acyclic carbene (NAC)c omplexes are formed. These undergo ring closure and elimination to the unsaturated NHC complexes upon addition of acid. This simples trategyo pens an attractive and fast approach to NHC complexes of gold, palladium and platinum. Them odular approach allowsafast modification and is well-suited for the synthesiso fu nsymetrically and symmetricallys ubstituted unsaturated NHC complexes.Scheme 1. NHC-Synthesis via metal isonitrile precursors; left:i ntermolecular process,r ight:i ntramolecular process.

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Complexes with Protic N‐Heterocyclic Carbene (NR,NH‐NHC) Ligands

Cited by 5 publications

References 139 publications

Synthesis of Different Classes of Six-Membered Gold(I) NHC Complexes by the Isonitrile Route

Synthesis of Different Classes of Six-Membered Gold(I) NHC Complexes by the Isonitrile Route

Trifunctional pNHC, Imine, Pyridine Pincer-Type Iridium(III) Complexes: Synthetic, Structural, and Reactivity Studies

From Isonitriles to Unsaturated NHC Complexes of Gold, Palladium and Platinum

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