A stable (amino)(phosphino)carbene as bidentate ligand for palladium and nickel complexes: Synthesis, structure, and catalytic activity

Teuma, Emmanuelle; Lyon‐Saunier, Celine; Gornitzka, Heinz; Mignani, Gérard; Baceiredo, Antoine; Bertrand, Guy

doi:10.1016/j.jorganchem.2005.06.036

Cited by 23 publications

(18 citation statements)

References 34 publications

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“…[124] 2.3.6. Cyclic Alkyl(amino)carbenes (CAACs) Some years before the preparation of the first N-heterocyclic carbene by Arduengo et al [30] Bertrand et al described the stable (trimethylsilyl)[bis(diisopropylamino)phosphanyl]carbene 35 [8] and shortly thereafter the molecular structure of a crystalline phosphanyl(silyl)carbene [125] The stable noncyclic heteroatom-stabilized carbenes 36, [9] 37, [126] 38, [127] 39, [128] and 40 [129] have also been prepared (Scheme 43). [130] The synthesis of the phosphanyl(aryl)carbene 41 [131] marked the entrance into the chemistry of stable singlet carbenes which are stabilized by only one heteroatom.…”

Section: Heterocyclic Carbenesmentioning

confidence: 99%

Heterocyclic Carbenes: Synthesis and Coordination Chemistry

2008

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The chemistry of heterocyclic carbenes has experienced a rapid development over the last years. In addition to the imidazolin-2-ylidenes, a large number of cyclic diaminocarbenes with different ring sizes have been described. Aside from diaminocarbenes, P-heterocyclic carbenes, and derivatives with only one, or even no heteroatom within the carbene ring are known. New methods for the synthesis of complexes with N-heterocyclic carbene ligands such as the oxidative addition or the metal atom template controlled cyclization of beta-functionalized isocyanides have been developed recently. This review summarizes the new developments regarding the synthesis of N-heterocyclic carbenes and their metal complexes.

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Section: Heterocyclic Carbenesmentioning

confidence: 99%

Heterocyclic Carbenes: Synthesis and Coordination Chemistry

2008

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“…The generation of the carbene-like complex 1 (with the topology of a four-membered N-heterocyclic "Arduengo carbene", NHC) [14] and its disappearance with the formation of complex 2 deserves some comments. The key species for the formation of 1 and 2 and hence for the reductive metalpromoted C À C bond formation seems to be the biradical cyclic titanium(III) carbene-like species 3 (J and K in Scheme 5).…”

Section: Angewandte Chemiementioning

confidence: 99%

[Cp₂Ti^III(NCy)₂CTi^IIICp₂]: A Transient Titanocene Carbene Complex?

et al. 2010

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Metallacycles of transition metals are important for many synthetic and catalytic applications. [1] In recent years, our interest has focused on the synthesis, formation, and reactions of three-, four-, and five-membered titana-, zircona-, and hafnacycles, [1,2] which could be obtained by utilizing the reactive metallocene fragment {Cp 2 M} (M = Ti,Zr,Hf) "hidden" in a h 2 -bounded bis(trimethylsilyl)acetylene complex. The scope for using such metallocene complexes in catalytic or stoichiometric reactions resulting, for example, in unusual all-carbon-metallacycles has been shown on numerous occasions. [1,2] Steric strain needs to be addressed, especially when cumulated double or triple bonds are part of small all-carbon metallacycles.[3] For example, Johnson et al. calculated ringtension energies of 55 kcal mol À1 for 1,2-cyclopentadiene and 90 kcal mol À1 for 1,2-cyclobutadiene.[3f] Stabilization of small strained metallacycles is achieved by means of complexation and incorporation of external substituents.[1, 2, 4] As a result of rehybridization effects, the external complexation of a metal center to C=C=C=C, C=C=C, or CC moieties significantly reduces ring tension. But also internal complexation (that is, complexation of a metal center inside the ring) is observed, which is responsible for the stabilization of unusual sterically strained five-membered metallacycles of the early transition metals Ti, Zr, and Hf, such as metallacyclocumulenes (1-metallacyclopenta-2,3,4-trienes; A), metallacyclopentynes (1-metallacyclopent-3-ynes; B), and metallacycloallenes (1-metallacyclopenta-2,3-dienes; C, Scheme 1). Also isolobal substitution of carbon atoms by heteroatoms decreases ring tension owing to longer heteroatom-carbon bonds. [1,2] Decreasing the ring size leads to increased steric strain which was expected when dealing with four-membered allcarbon-metallacycles, such as metallacycloallenes (1-metallacyclobuta-2,3-dienes; D) or diverse metallaheterocycloallenes (Scheme 2). To date we have not succeeded in isolating metallacycloallenes but following our interest in Group 4 metallacycle chemistry with strained rings, [1][2][3] we describe herein, for the first time, the synthesis, isolation, and full characterization of a formal titanaheterocycloallene of type E, however, it is not stabilized by an internal coordination mode as displayed in Scheme 2 but by external complexation resulting in the formation of a four-membered carbenelike complex (Scheme 2, F; Figure 1). Schrock and co-workers have prepared complexes featuring such allene moieties, for example, [Mo{C 3 (tBu) 2 }{OCH(CF 3 ) 2 } 2 (py) 2 ] (py = pyridine) and [CpW{C 3 (tBu) 2 }]Cl. When one equivalent of 1,3-N,N'-dicyclohexylcarbodiimide dissolved in n-hexane was added to a solution of [Cp 2 Ti(h 2 -Me 3 SiC 2 SiMe 3 )], the light brown solution changed immediately to red. The color change indicated that Ti II was oxidized to corresponding Ti III (Scheme 3). Within 12 h at room temperature deep red crystals (black appearance) were formed. Astonishingly, th...

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“…Die Bildung des Carben-ähnlichen Komplexes 1 (mit der Topologie eines viergliedrigen N-heterocyclischen "Arduengo-Carbens", NHC) [14] und sein Verschwinden bei gleichzeitiger Bildung von 2 verdienen einige grundlegende Bemerkungen. Die Schlüsselspezies für die Bildung von 1 und 2 und damit für die reduktive Metall-unterstützte C-C-Bindungsknüpfung scheint die biradikalische cyclische Carben-ähnli-che Ti III -Spezies 3 (wie in J und K in Schema 5) zu sein.…”

Section: In Memoriam Herbert Schumannunclassified

[Cp₂Ti^III(NCy)₂C‐Ti^IIICp₂]: ein transienter Titanocen‐Carbenkomplex?

et al. 2010

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Carben oder doch kein Carben? Durch den Einsatz von [Cp2Ti(η2‐Me3SiC2SiMe3)] (Cp=Cyclopentadienyl) als Reduktionsmittel wie auch als Abfangreagens gelang es, in der Reaktion mit RNCNR einen ungewöhnlichen, paramagnetischen Titanocen(III)‐Carben‐ähnlichen Komplex zu isolieren. Dieser Dimetallkomplex verfügt über die Topologie eines viergliedrigen NHC‐Komplexes (NHC=N‐heterocyclisches Carben) mit TiIII als Teil des Heterocyclus (siehe Struktur).

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A stable (amino)(phosphino)carbene as bidentate ligand for palladium and nickel complexes: Synthesis, structure, and catalytic activity

Cited by 23 publications

References 34 publications

Heterocyclic Carbenes: Synthesis and Coordination Chemistry

Heterocyclic Carbenes: Synthesis and Coordination Chemistry

[Cp₂Ti^III(NCy)₂CTi^IIICp₂]: A Transient Titanocene Carbene Complex?

[Cp₂Ti^III(NCy)₂C‐Ti^IIICp₂]: ein transienter Titanocen‐Carbenkomplex?

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A stable (amino)(phosphino)carbene as bidentate ligand for palladium and nickel complexes: Synthesis, structure, and catalytic activity

Cited by 23 publications

References 34 publications

Heterocyclic Carbenes: Synthesis and Coordination Chemistry

Heterocyclic Carbenes: Synthesis and Coordination Chemistry

[Cp2TiIII(NCy)2CTiIIICp2]: A Transient Titanocene Carbene Complex?

[Cp2TiIII(NCy)2C‐TiIIICp2]: ein transienter Titanocen‐Carbenkomplex?

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[Cp₂Ti^III(NCy)₂CTi^IIICp₂]: A Transient Titanocene Carbene Complex?

[Cp₂Ti^III(NCy)₂C‐Ti^IIICp₂]: ein transienter Titanocen‐Carbenkomplex?