PH-funktionelle ZirkonocenPhosphido-Komplexe—Synthese von Cp2ZrPH(2,4,6-tBu3C6H2)(X) {Cp  C5H5, X  Cl, PH(2,4,6- tBu3C6H2)} und Molekülstruktur von Cp2Zr{PH(2,4,6-tBu3C6H2) }2

Hey‐Hawkins, Evamarie; Kurz, Stefan

doi:10.1016/0022-328x(94)84099-7

Cited by 36 publications

(13 citation statements)

References 23 publications

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“…Occassionally, even C -C activation in the sidechain is observed [ 152 ]. Similar C -H activation is observed in transition metal phosphides, especially when the phosphorus ligand has a SMes substituent [ 153 ].…”

Section: Note : Sterically Bulky Ligands Accelerate Reductive Eliminamentioning

confidence: 54%

The Nature of N‐Heterocyclic Carbenes

Kühl

2010

Functionalised N‐Heterocyclic Carbene Complexes

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There are essentially three different types of transition metal carbene complexes featuring three different types of carbene ligands. They have all been named after their fi rst discoverers: Fischer carbenes [ 27 -29 ], Schrock carbenes [ 30 , 31 ] and Wanzlick -Arduengo carbenes (see Figure 1.1 ). The latter, also known as N -heterocyclic carbenes (NHC), should actually be named after three people: Ö fele [ 2 ] and Wanzlick [ 3 ], who independently synthesised their fi rst transition metal complexes in 1968, and Arduengo [ 1 ] who reported the fi rst free and stable NHC in 1991. Fischer carbene complexes have an electrophilic carbene carbon atom [ 32 ] that can be attacked by a Lewis base. The Schrock carbene complex has a reversed reactivity. The Schrock carbene complex is usually employed in olefi n metathesis (Grubbs ' catalyst) or as an alternative to phosphorus ylides in the Wittig reaction [ 33 ].The NHC are different from both other types. They form transition metal complexes that are essentially inert, although exceptions are known. Their exceptional stability derives from their intrinsic stabilisation from the N -C p π -p π bonding interaction of the nitrogen atoms fl anking the carbene carbon atom. The p orbital of the carbon is thus partially fi lled and no longer available for nucleophilic attack. Also, it does not have a lone pair of its own with which it could possibly engage in a nucleophilic interaction of its own. Hence, it remains unreactive taking the middle ground between the opposing reactivities of Fischer and Schrock carbenes. It is this apparent lack of reactivity that meant that the transition metal NHC complexes received little attention in their early history. Functionalised N-Heterocyclic Carbene ComplexesOlaf Kühl

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Section: Note : Sterically Bulky Ligands Accelerate Reductive Eliminamentioning

confidence: 54%

The Nature of N‐Heterocyclic Carbenes

Kühl

2010

Functionalised N‐Heterocyclic Carbene Complexes

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“…The phosphinidene has only been captured with PMe 3 in the case of 6 where R = Mes* and the Cpligands on Zr are unsubstituted [10d]. Phosphinidenes 6 are typically suggested to result form direct elimination of a phosphine (path C) [10,15], while H-transfer and ligand exchange (path D) has so far not been considered as an alternative. Because dissociation of PMe 3 from 1 occurs easily and hence also the exchange of phosphine ligands, path D may indeed be the more viable one.…”

Section: Formation Of Zirconocene Phosphinidene Complex 1mentioning

confidence: 99%

“…The calculated bond distances and angles of the model structures 1 0 , 2, 3 0 , and 5 0 are listed in Table 1 together with the reported crystal structure data for Cp 2 (PMe 3 )Zr@PMes* (1) [10d], Cp 2 ZrCl 2 (2) [28], Cp 2 ClZr(PHDmp) (3-Dmp, Dmp = 2,6-Mes 2 Ph) [29], and Cp 2 ZrðPMes Ã 2 Þ 2 (5-Mes*) [30]. The DFT calculated bond distances are in good agreement with the experimental ones.…”

Section: Structuresmentioning

confidence: 99%

“…6 0 , path C) is unlikely in light of the endothermicity of 32.5 kcal/mol. Reactive phosphinidenes 6 with various P-substituents and Cp-type ligands are suggested as reactive intermediates in the thermal decomposition reactions of diphosphide complexes 5 [15]. The phosphinidene has only been captured with PMe 3 in the case of 6 where R = Mes* and the Cpligands on Zr are unsubstituted [10d].…”

Section: Formation Of Zirconocene Phosphinidene Complex 1mentioning

confidence: 99%

“…For neither route could the intermediate formation of the 16-electron phosphinidene complex 6 be confirmed experimentally. The only intermediate detected by 31 P NMR spectroscopy was zirconium diphosphide complex (5, d 51.6 ppm) when two equivalents of lithium phosphide were used [15]. This diphosphide may undergo intramolecular H-transfer (a) to phosphine-stabilized phosphinidene 1* followed by trimethylphosphine ligand exchange to give 1 (pathway D) or (b) eliminate the ancillary primary phosphine ligand (PH 2 R) first to form the intermediate 16-electron phosphinidene complex 6 (pathway C).…”

Section: Introductionmentioning

confidence: 99%

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Toward the catalytic synthesis of phosphiranes. A computational study

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Zirconium-Phosphor-Chemie: Synthesestrategien, Reaktivität, Katalyse und Nutzen

Stephan¹

2000

Angewandte Chemie

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Rasant entwickelt hat sich in den letzten Jahren die Chemie von Komplexen mit Zr‐P‐Bindungen und die Anwendung dieser Verbindungen in der Organophosphorchemie. Dies gilt besonders für die Synthese und die Reaktivität von Verbindungen mit Zr‐P‐Einfach‐ und ‐Doppelbindungen sowie von Phosphazirconacyclen und von Zr‐Komplexen mit unsubstituierten Phosphorliganden. Die Einsatzmöglichkeiten in der stöchiometrischen und der katalytischen Synthese eröffnen einen Zugang zu einer Vielzahl neuartiger Organophosphorverbindungen und veranschaulichen die Leistungsfähigkeit der Organometallchemie bei der Synthese von Hauptgruppenelementverbindungen.

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PH-funktionelle ZirkonocenPhosphido-Komplexe—Synthese von Cp2ZrPH(2,4,6-tBu3C6H2)(X) {Cp  C5H5, X  Cl, PH(2,4,6- tBu3C6H2)} und Molekülstruktur von Cp2Zr{PH(2,4,6-tBu3C6H2) }2

Cited by 36 publications

References 23 publications

The Nature of N‐Heterocyclic Carbenes

The Nature of N‐Heterocyclic Carbenes

Toward the catalytic synthesis of phosphiranes. A computational study

Zirconium-Phosphor-Chemie: Synthesestrategien, Reaktivität, Katalyse und Nutzen

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