Recent Advances in the Chemistry of Metal-Carbon Triple Bonds

Mayr, Andreas; Hoffmeister, Hans Martin

doi:10.1016/s0065-3055(08)60481-5

Cited by 181 publications

(55 citation statements)

References 218 publications

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“…A single-crystal X-ray diffraction (XRD) study of 2 confirmed the proposed assignment ( Figure 1). The short C31-C32 bond length and wide C31-C32-O1 angle (1.2885 (11) Å and 179.01°, respectively) support assignment of the η 1 -C(P)=C=O bonding motif. 33 Mo engages the central arene in an η 6 fashion, to stabilize the low-valent metal center resulting from C-C coupling.…”

Section: Scheme 2 Co Coupling Chemistry Of Terminal Molybdenum Carbimentioning

confidence: 62%

“…The elementary step of C-C coupling between CO and surface hydrocarbons has been studied extensively in model systems. 1,[11][12][13][14] In contrast, the investigation of carbide/CO coupling remains largely underexplored. In seminal studies of carbonyl-bridged metal carbide ensembles, 15 more exposed carbides demonstrated enhanced reactivity, including C/CO coupling in the Fe3 cluster.…”

Section: Introductionmentioning

confidence: 99%

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CO Coupling Chemistry of a Terminal Mo Carbide: Sequential Addition of Proton, Hydride, and CO Releases Ethenone

et al. 2019

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The mechanism originally proposed by Fischer and Tropsch for carbon monoxide (CO) hydrogenative catenation involves CC coupling from a carbide-derived surface methylidene. A single molecular system capable of capturing these complex chemical steps is hitherto unknown. Herein, we demonstrate the sequential addition of proton and hydride to a terminal Mo carbide derived from CO. The resulting anionic methylidene couples with CO (1 atm.) at low-temperature (-78 °C) to release ethenone. Importantly, the synchronized delivery of two reducing equivalents and an electrophile, in the form of a hydride (H-= 2e-+ H +), promotes alkylidene formation from the carbyne precursor and enables coupling chemistry, under conditions milder than those previously described with strong one-electron reductants and electrophiles. Thermodynamic measurements bracket the hydricity and acidity requirements for promoting methylidene formation from carbide as energetically viable upon formal heterolysis of H2. Methylidene formation prior to CC coupling proves critical for organic product release, as evidenced by direct carbide carbonylation experiments. Spectroscopic studies, a monosilylated model system, and Quantum Mechanics computations provide insight into the mechanistic details of this reaction sequence, which serves as a rare model of the initial stages of the Fischer Tropsch synthesis.

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Section: Scheme 2 Co Coupling Chemistry Of Terminal Molybdenum Carbimentioning

confidence: 62%

Section: Introductionmentioning

confidence: 99%

CO Coupling Chemistry of a Terminal Mo Carbide: Sequential Addition of Proton, Hydride, and CO Releases Ethenone

et al. 2019

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“…An extensive description of protocols to achieve group 6 M≡C linkages have been reported, and we refer the reader to this work 6h. However, prior to group 6 transition metals, M≡CR linkages are far more scarce 4c.…”

Section: Introductionmentioning

confidence: 99%

What a Difference One Electron Makes! Generating Low‐Coordinate Ti–C and V–C Multiply Bonded Frameworks through One Electron Oxidatively Induced α‐Hydrogen Abstractions

2006

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Low‐coordinate, high oxidation state titanium and vanadium complexes containing terminal metal–carbon multiply bonded functionalities have been prepared directly or indirectly through one electron oxidatively induced α‐hydrogen abstraction reactions. This synthetic approach offers a mild entry to reactive M=C and M≡C motifs, and does not depend on external stimulants such as heat, light or base to promote the α‐hydrogen‐abstraction step. In addition, this strategic protocol avoids the use of powerful electrophiles, thus generating terminal and nucleophilic M–C multiple bonds in low‐coordination environments. In some cases terminal alkylidenes containing β‐hydrogen atoms can also be introduced through this route. This microreview surveys the synthesis and chemistry surrounding isolable titanium and vanadium complexes bearing terminal alkylidene and alkylidyne ligands. Particular emphasis will be placed on the synthesis of the high oxidation state M–C multiple bond. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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“…Addition of one equivalent of C 6 H 5 COX, where X=Cl, Br, to an ethereal solution of 3 and 4 , respectively, elicits a quick color change to royal purple at room temperature. As indicated by 1 H NMR spectroscopy, both of these two reactions proceed cleanly and unexpectedly yield solely the benzylidyne products [Mo 2 (X)(μ‐X)(μ‐CPh)(κ 2 ‐O 2 CPh){μ‐κ 2 ‐HC(N‐2,6‐ i Pr 2 C 6 H 3 ) 2 } 2 ] (X=Cl ( 8 ), Br ( 9 )) in good yields after 0.5 h stirring 24. 25 The steric effect is observed when 5 is treated with 1 equivalent of o ‐toluoyl chloride in diethyl ether, the bridging benzylidyne species [Mo 2 (Cl)(μ‐Cl)(μ‐C‐2‐MeC 6 H 4 )(κ 2 ‐O 2 C‐2‐MeC 6 H 4 ){μ‐κ 2 ‐HC(N‐2,6‐ i Pr 2 C 6 H 3 ) 2 } 2 ] ( 10 ) is also formed, but to expedite this reaction, it is carried out at 60 °C for 4 h to reach completion.…”

Section: Methodsmentioning

confidence: 99%

Haloacylation of the Quintuple‐Bonded Group VI Metal Amidinate Dimers and Disproportionation of Acyl Groups to Form Carbynes

et al. 2013

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Fünf ist Trumpf: Fünffachbindungen von Gruppe‐VI‐Metallen können Friedel‐Crafts‐Halogenacylierungen eingehen. Entsprechende Dimolybdänkomplexe reagieren mit einem Äquivalent RCOX (R=Me, C6H5, 2‐MeC6H4; X=Cl, Br) zu Acylkomplexen mit Metall‐Metall‐Vierfachbindung. Der Zusatz eines zweiten Äquivalents an Acylhalogenid führt zu einer Disproportionierung unter Bildung von Dimolybdän‐Carbin‐Carboxylat‐Komplexen.

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Recent Advances in the Chemistry of Metal-Carbon Triple Bonds

Cited by 181 publications

References 218 publications

CO Coupling Chemistry of a Terminal Mo Carbide: Sequential Addition of Proton, Hydride, and CO Releases Ethenone

CO Coupling Chemistry of a Terminal Mo Carbide: Sequential Addition of Proton, Hydride, and CO Releases Ethenone

What a Difference One Electron Makes! Generating Low‐Coordinate Ti–C and V–C Multiply Bonded Frameworks through One Electron Oxidatively Induced α‐Hydrogen Abstractions

Haloacylation of the Quintuple‐Bonded Group VI Metal Amidinate Dimers and Disproportionation of Acyl Groups to Form Carbynes

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