Size Effects in Gas‐phase C−H Activation

Yuan, Bowei; Tang, Shi-Ya; Zhou, Shaodong

doi:10.1002/cphc.202200769

Cited by 4 publications

(2 citation statements)

References 130 publications

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“…Metal–metal bonds are ubiquitous in atomic clusters composed of multiple metal atoms, which provide an excellent platform to explore the critical role of metal–metal interaction displayed in activation and transformation of inert molecules. With the development of experimental techniques (e.g., laser vaporization) for preparation of metal clusters in isolated gas-phase environments, the reactivity of transition metal clusters toward methane has gained great attention in the area of cluster science since 1980s. − A considerable number of bare noble metal (NM) clusters in different charge states (e.g., Pd n ≤23 , Pt n ≤24 ± , Rh n ≤10 − ) were observed to dehydrogenate methane at room temperature. Available mechanistic studies revealed that single NM atoms generally serve as reactive sites to bring about C–H activation.…”

Section: Introductionmentioning

confidence: 99%

Conversion of Methane at Room Temperature Mediated by the Ta–Ta σ-Bond

Li,

Liu,

Zhao

et al. 2024

JACS Au

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Metal−metal bonds constitute an important type of reactive centers for chemical transformation; however, the availability of active metal−metal bonds being capable of converting methane under mild conditions, the holy grail in catalysis, remains a serious challenge. Herein, benefiting from the systematic investigation of 36 metal clusters of tantalum by using mass spectrometric experiments complemented with quantum chemical calculations, the dehydrogenation of methane at room temperature was successfully achieved by 18 cluster species featuring σ-bonding electrons localized in single naked Ta−Ta centers. In sharp contrast, the other 18 remaining clusters, either without naked Ta−Ta σ-bond or with σbonding electrons delocalized over multiple Ta−Ta centers only exhibit molecular CH 4adsorption reactivity or inertness. Mechanistic studies revealed that changing cluster geometric configurations and tuning the number of simple inorganic ligands (e.g., oxygen) could flexibly manipulate the presence or absence of such a reactive Ta−Ta σ-bond. The discovery of Ta−Ta σ-type bond being able to exhibit outstanding activity toward methane conversion not only overturns the traditional recognition that only the metal−metal πor δ-bonds of early transition metals could participate in bond activation but also opens up a new access to design of promising metal catalysts with dual-atom as reactive sites for chemical transformations.

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Section: Introductionmentioning

confidence: 99%

Conversion of Methane at Room Temperature Mediated by the Ta–Ta σ-Bond

Li,

Liu,

Zhao

et al. 2024

JACS Au

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“…Distinctly, the acetonitrile (CH 3 CN) ligand was found to switch the mechanism of methane activation mediated by diatomic cation ZnO + , ultimately resulting in the improvement of product selectivity at the expense of activity. In sharp contrast with the extensively investigated single-metal systems, the preparation and reactivity study of the ligated or “supported” metal clusters, which represent important classes of heterogeneous ,,− catalysts for many reactions, were rarely investigated in the gas phase, despite that a considerable number of free metal clusters and metal compound (oxide, carbide, nitride, and boride) clusters being capable of activation and functionalization of methane under mild conditions have been reported in the literature. ,,− ,− …”

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confidence: 99%

Activation of Methane by Rhodium Clusters on a Model Support C₂₀H₁₀

Zhao,

Zhao

et al. 2023

J. Phys. Chem. Lett.

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Supported metals represent an important family of catalysts for the transformation of the most stable alkane, methane, under mild conditions. Here, using state-of-the-art mass spectrometry coupled with a newly designed double ion trap reactor that can run at high temperatures, we successfully immobilize a series of Rh n − (n = 4−8) cluster anions on a model support C 20 H 10 . Reactivity measurements at room temperature identify a significantly enhanced performance of large-sized Rh 7,8 C 20 H 10 − toward methane activation compared to that of free Rh 7,8 − . The "support" acting as an "electron sponge" is emphasized as the key factor to improve the reactivity of large-sized clusters, for which the high electron-withdrawing capability of C 20 H 10 dramatically shifts the active Rh atom from the apex position in free Rh 7 − to the edge position in "supported" Rh 7 − to enhance CH 4 adsorption, while the flexibility of C 20 H 10 to release electrons further promotes subsequent C−H activation. The Rh atoms in direct contact with the support serve as electron-relay stations for electron transfer between C 20 H 10 and the active Rh atom. This work not only establishes a novel approach to prepare and measure the reactivity of "supported" metal clusters in isolated gas phase but provides useful atomic-scale insights for understanding the chemical behavior of carbon (e.g., graphene)-supported metals in heterogeneous catalysis.

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High-temperature reactivity of vanadium oxide clusters in methane activation: Vibrational degrees of freedom matter

Ruan

Zhao

Wei

et al. 2023

The Journal of Chemical Physics

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Understanding the properties of small particles working under high-temperature conditions at the atomistic scale is imperative for exact control of related processes, but it is quite challenging to achieve experimentally. Herein, benefitting from state-of-the-art mass spectrometry and by using our newly designed high-temperature reactor, the activity of atomically precise particles of negatively charged vanadium oxide clusters toward hydrogen atom abstraction (HAA) from methane, the most stable alkane molecule, has been measured at elevated temperatures up to 873 K. We discovered the positive correlation between the reaction rate and cluster size that larger clusters possessing greater vibrational degrees of freedom can carry more vibrational energies to enhance the HAA reactivity at high temperature, in contrast with the electronic and geometric issues that control the activity at room temperature. This finding opens up a new dimension, vibrational degrees of freedom, for the simulation or design of particle reactions under high-temperature conditions.

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Size Effects in Gas‐phase C−H Activation

Cited by 4 publications

References 130 publications

Conversion of Methane at Room Temperature Mediated by the Ta–Ta σ-Bond

Conversion of Methane at Room Temperature Mediated by the Ta–Ta σ-Bond

Activation of Methane by Rhodium Clusters on a Model Support C₂₀H₁₀

High-temperature reactivity of vanadium oxide clusters in methane activation: Vibrational degrees of freedom matter

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Size Effects in Gas‐phase C−H Activation

Cited by 4 publications

References 130 publications

Conversion of Methane at Room Temperature Mediated by the Ta–Ta σ-Bond

Conversion of Methane at Room Temperature Mediated by the Ta–Ta σ-Bond

Activation of Methane by Rhodium Clusters on a Model Support C20H10

High-temperature reactivity of vanadium oxide clusters in methane activation: Vibrational degrees of freedom matter

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Product

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Activation of Methane by Rhodium Clusters on a Model Support C₂₀H₁₀