Darstellung eines dimetallacyclopropen-komplexes durch insertion von methylisonitril in eine WHW-Brücke

Alt, Helmut G.; Frister, Thomas

doi:10.1016/0022-328x(85)80255-2

Cited by 9 publications

(8 citation statements)

References 11 publications

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“…These are characteristic features of μ 2 -CNHR ligands (cf. 317.4 and 8.61 ppm, respectively, for [W 2 Cp 2 (μ-CNHMe)(H)(CO) 4 ]) . Finally, since the coordination number around the metal atoms in this type of structure is not greatly modified with respect to that in the parent compound 1 , then the P–W couplings are expected to remain high, in agreement with the average values of ca.…”

Section: Resultssupporting

confidence: 75%

“…52 An empirical absorption correction was applied using the SCALE3 ABSPACK algorithm as implemented in the latter program. Structure solution and refinements were performed as described above, with all hydrogen atoms being geometrically placed and refined using a riding model except for H (11), which was located in the Fourier maps and was refined isotropically. All non-hydrogen atoms were refined anisotropically.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…Notably, no interconversion between isomers A and C was observed by these authors at their triosmium complexes. 7 In apparent contrast with these findings, Alt et al found a few years later that the ditungsten hydride [W 2 Cp 2 (μ-H) 2 (CO) 4 ] would react with CNMe in a nonpolar solvent such as toluene to directly give the aminocarbyne derivative below room temperature, 11 rather pointing to an intramolecular formation of the aminocarbyne complex. More recently, Fujita et al found that the diiridum hydride [Ir 2 Cp* 2 (μ-H) 2 (μ-Me 2 PCH 2 PMe 2 )] 2+ reacted in methanol with CNR (R = Ph, Cy, but not t Bu) to give also the corresponding aminocarbyne derivative of type C, but even if the authors pointed to steric effects to explain their observations, 12 the operation of a deprotonation/reprotonation sequence should not be excluded in that system.…”

Section: ■ Introductionmentioning

confidence: 97%

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Insertion, Rearrangement, and Coupling Processes in the Reactions of the Unsaturated Hydride Complex [W₂(η⁵-C₅H₅)₂(H)(μ-PCy₂)(CO)₂] with Isocyanides

et al. 2013

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The title complex reacted with stoichiometric amounts of CNR rapidly at room temperature or below to give two types of formimidoyl derivatives: the symmetrically bridged complexes [W 2 Cp 2 (μ-C,N:C,N-HCNR)(μ-PCy 2 )(CO) 2 ] (R = t Bu (W−W = 2.8645(5) Å), 4-C 6 H 4 OMe), and the asymmetrically bridged [W 2 Cp 2 {μ-C:N-HCN(Xyl)}(μ-PCy 2 )(CO) 2 ] (Cp = η 5 -C 5 H 5 ; Xyl = 2,6-C 6 H 3 Me 2 ). The latter complex underwent slow isomerization at room temperature to give the corresponding aminocarbyne derivative [W 2 Cp 2 {μ-CNH(Xyl)}(μ-PCy 2 )(CO) 2 ], which in turn could be decarbonylated through irradiation with UV−vis light to yield the 30-electron aminocarbyne complex [W 2 Cp 2 {μ-CNH(Xyl)}(μ-PCy 2 )(μ-CO)] (W−W = 2.4928(4) Å). Density functional theory calculations revealed that the aminocarbyne complex was the most stable isomer for the three isocyanides under study, while subtle steric effects marked the relative stability of the formimidoyl isomers, which therefore are the kinetic products of these reactions. The reaction of the title complex with excess CN(4-C 6 H 4 OMe) at room temperature gave in good yield the complex [W 2 Cp 2 (μ-C,N:C,C′-HCN(4-C 6 H 4 OMe)C{N(4-C 6 H 4 OMe)})(μ-PCy 2 )(CO) 2 ] (W−W = 2.9370(2) Å), having a 5-electron donor aminocarbene-iminoacyl ligand derived from the N−C coupling of formimidoyl and isocyanide ligands, whereas the analogous reaction with CNXyl gave the aminocarbyne complex [W 2 Cp 2 {μ-CNH(Xyl)}(μ-PCy 2 ){CN(Xyl)}(CO)] (W−W = 2.677(2) Å) having a terminal bent isocyanide ligand.

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Section: Resultssupporting

confidence: 75%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 97%

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Insertion, Rearrangement, and Coupling Processes in the Reactions of the Unsaturated Hydride Complex [W₂(η⁵-C₅H₅)₂(H)(μ-PCy₂)(CO)₂] with Isocyanides

et al. 2013

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“…315 ppm. For comparison, we note that the latter figures are quite similar to those measured in related aminocarbyne complexes such as [W 2 Cp 2 (μ-CNHMe)(μ-H)(CO) 4 ] (317.4 ppm) and in the crystallographically characterized [W 2 Cp 2 {μ-CNH(Xyl)}(μ-PCy 2 )(CO)(CNXyl)] (ca. 336 ppm) .…”

Section: Resultssupporting

confidence: 78%

Hydrogen Atom Transfer Reactions of the Unsaturated Hydroxycarbyne Complex [W₂Cp₂(μ-COH)(μ-PPh₂)₂]BF₄

et al. 2013

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The hydroxycarbyne complex salt [W2Cp2(μ-COH)(μ-PPh2)2]BF4 (1) reacted rapidly with water in the presence of the oxidant [FeCp2]BF4 to give the hydroxo complex salt [W2Cp2(OH)(μ-PPh2)2(CO)]BF4, a preparation that could be replicated using the neutral carbonyl complex [W2Cp2(μ-PPh2)2(μ-CO)] (2) instead. A similar reaction took place slowly with HSPh and rapidly in the presence of [FeCp2]BF4, to yield the known 32-electron complex salt [W2Cp2(SPh)(μ-PPh2)2(CO)]BF4. In contrast, 1 did not react with PhOH or H2Np-tol even in the presence of [FeCp2]BF4. However, a fast reaction between these molecules and 2 took place in the presence of [FeCp2]BF4, to give the phenolato complex salt [W2Cp2(OPh)(μ-PPh2)2(CO)]BF4 and the imido-hydride [W2Cp2(μ-H)(Np-tol)(μ-PPh2)2(CO)]BF4 (W–W = 2.9135(8) Å), respectively, after formal elimination of hydrogen. The hydroxycarbyne complex 1 reacted rapidly with PH2Cy to give the hydride derivative [W2Cp2(H)(μ-PPh2)2(CO)(PH2Cy)]BF4, this requiring H-migration from O to W atoms. The M–H bonds in the latter hydride cations were deprotonated by strong bases to give the corresponding neutral complexes [W2Cp2(Np-tol)(μ-PPh2)2(CO)] and [W2Cp2(μ-PPh2)2(CO)(PH2Cy)]. Compound 1 also reacted easily with two-electron donors such as NCMe, CN t Bu, and CNp-tol, to give products derived from the addition of two molecules of reagent in each case, and some rearrangement of the COH ligand. The first reaction gave the new cationic complex [W2Cp2(μ-PPh2)2(μ-N:N,N′-N2HC2Me2)(CO)]BF4, derived from the C–C coupling of two nitrile molecules accompanied by an O to N shift of the hydroxycarbyne proton. In contrast, no C–C coupling processes were observed in the reactions with isocyanides, although proton migration occurred in all cases, either to the metal (reaction with CN t Bu), to give the hydride [W2Cp2(H)(μ-PPh2)2(μ-CN t Bu)(CN t Bu)]BF4, or to the N atom of one of the incoming isocyanides (reaction with CNp-tol), to give the aminocarbyne derivative [W2Cp2{μ-CN(H)p-tol}(μ-PPh2)2(CNp-tol)(CO)]BF4.

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“…The formation of aminocarbyne complexes in previous reactions seems to be associated with the use of strong donor solvents and might be base-catalyzed. 23 However, we note that the 32-electron ditungsten hydride [W 2 Cp 2 (μ-H) 2 (CO) 4 ] reacted with CNMe in toluene solution at room temperature to selectively yield the corresponding aminocarbyne derivative, 24 thus suggesting that intramolecular pathways might also lead to the eventual formation of N−H bonds. Unfortunately, we have not been able to find experimental conditions to fully drive the above reactions of 1 toward one or another product, although separate experiments indicated that formation of the formimidoyl derivative 6 was prevalent when the reaction was carried out at room temperature, whereas the aminocarbyne complex 7 was preferentially formed when the reaction was performed at 273 K, while a low isocyanide concentration was maintained during the process (see the Experimental Section).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

E–H Bond Activation and Insertion Processes in the Reactions of the Unsaturated Hydride [W₂Cp₂(μ-H)(μ-PPh₂)(NO)₂]

et al. 2018

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The reactions of the title complex (1) with different p-block element (E) molecules was examined. Compound 1 reacted with BH·THF at room temperature to give the trihydride [WCp(μ-H)H(μ-PPh)(NO)], which formally results from hydrogenation of 1, a reaction that actually does not take place when neat dihydrogen is used. Clean E-H bond oxidative addition, however, took place when 1 was reacted with HSnPh, to give the related dihydride stannyl derivative [WCp(μ-H)H(μ-PPh)(NO)(SnPh)]. In contrast, the reaction of 1 with HSPh involved H elimination to give the thiolate-bridged complex [WCp(μ-SPh)(μ-PPh)(NO)], while that with (p-tol)C(O)H resulted in insertion of the aldehyde to yield the related alkoxide complex [WCp{μ-OCH(p-tol)}(μ-PPh)(NO)]. Insertion also prevailed in the reactions of 1 with CNBu, which, however, involved the competitive formation of new C-H or N-H bonds, to give a mixture of formimidoyl and aminocarbyne derivatives, [WCp(μ-κ:η-HCNBu)(μ-PPh)(NO)] (W-W = 3.0177(2) Å) and [WCp{μ-C(NHBu)}(μ-PPh)(NO)] (W-W = 2.9010(4) Å), respectively, even though the latter was thermodynamically preferred, according to density functional theory calculations. The former represents the first structurally characterized complex displaying a formimidoyl or iminoacyl ligand in the alkenyl-like μ-κ:η coordination mode. The reaction of 1 with diazomethane proceeded with N elimination and C-H coupling to yield the agostic methyl-bridged complex [WCp(μ-κ:η-CH)(μ-PPh)(NO)] (calculated W-W = 2.923 Å), whereas the reaction with NCH(SiMe) proceeded with insertion of the diazoalkane to give the corresponding hydrazonide complex [WCp{μ-NH(NCHSiMe)}(μ-PPh)(NO)] (W-W = 2.8608(4) Å). The latter was converted under alkaline conditions to the methyldiazenide derivative [WCp{μ-N(NMe)}(μ-PPh)(NO)] (W-W = 2.8730(2) Å), in a process involving hydrolysis of the C-Si bond coupled with a 1,3-H shift from N to C.

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Darstellung eines dimetallacyclopropen-komplexes durch insertion von methylisonitril in eine WHW-Brücke

Cited by 9 publications

References 11 publications

Insertion, Rearrangement, and Coupling Processes in the Reactions of the Unsaturated Hydride Complex [W₂(η⁵-C₅H₅)₂(H)(μ-PCy₂)(CO)₂] with Isocyanides

Insertion, Rearrangement, and Coupling Processes in the Reactions of the Unsaturated Hydride Complex [W₂(η⁵-C₅H₅)₂(H)(μ-PCy₂)(CO)₂] with Isocyanides

Hydrogen Atom Transfer Reactions of the Unsaturated Hydroxycarbyne Complex [W₂Cp₂(μ-COH)(μ-PPh₂)₂]BF₄

E–H Bond Activation and Insertion Processes in the Reactions of the Unsaturated Hydride [W₂Cp₂(μ-H)(μ-PPh₂)(NO)₂]

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Darstellung eines dimetallacyclopropen-komplexes durch insertion von methylisonitril in eine WHW-Brücke

Cited by 9 publications

References 11 publications

Insertion, Rearrangement, and Coupling Processes in the Reactions of the Unsaturated Hydride Complex [W2(η5-C5H5)2(H)(μ-PCy2)(CO)2] with Isocyanides

Insertion, Rearrangement, and Coupling Processes in the Reactions of the Unsaturated Hydride Complex [W2(η5-C5H5)2(H)(μ-PCy2)(CO)2] with Isocyanides

Hydrogen Atom Transfer Reactions of the Unsaturated Hydroxycarbyne Complex [W2Cp2(μ-COH)(μ-PPh2)2]BF4

E–H Bond Activation and Insertion Processes in the Reactions of the Unsaturated Hydride [W2Cp2(μ-H)(μ-PPh2)(NO)2]

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Insertion, Rearrangement, and Coupling Processes in the Reactions of the Unsaturated Hydride Complex [W₂(η⁵-C₅H₅)₂(H)(μ-PCy₂)(CO)₂] with Isocyanides

Insertion, Rearrangement, and Coupling Processes in the Reactions of the Unsaturated Hydride Complex [W₂(η⁵-C₅H₅)₂(H)(μ-PCy₂)(CO)₂] with Isocyanides

Hydrogen Atom Transfer Reactions of the Unsaturated Hydroxycarbyne Complex [W₂Cp₂(μ-COH)(μ-PPh₂)₂]BF₄

E–H Bond Activation and Insertion Processes in the Reactions of the Unsaturated Hydride [W₂Cp₂(μ-H)(μ-PPh₂)(NO)₂]