N-heterocyclic carbene coordinated metal nanoparticles and nanoclusters

Shen, Hongliang; Tian, Guolong; Xu, Zhen; Wang, Lingzheng; Qu, Wu; Zhang, Yuhao; Teo, Boon K.

doi:10.1016/j.ccr.2022.214425

Cited by 71 publications

(59 citation statements)

References 208 publications

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“…Together with the well-defined structures that can be determined by X-ray crystallography, the presence of both organic ligands and metal–metal bonds makes ligand-protected atomically precise metal nanoclusters (NCs) an ideal model catalyst system to bridge the gap between organometallic catalysts and metal nanocatalysts. − For example, the surface coordination structures of ligands, e.g., phosphine, thiolate, alkynyl, and N-heterocyclic carbene (NHC), on metal NCs have now been well demonstrated. ,, Moreover, the molecular understanding of their catalytic mechanism is expected to provide insights on how surface ligands and metal–metal interactions interplay together to determine the catalytic performance of metal catalysts. − Among them, the recently emerging Au NCs protected by NHCs are expected to serve as an ideal candidate for catalytic mechanism investigations due to their outstanding stability but possible presence of exposure metal sites. − On the other hand, homogeneous gold catalysts with NHC-Au-X structures have been widely applied in chemical transformations, including, but not limited to, the activation and transformation of alkynes, alkenes, and allenes . While the NHC ligands prevent the complex decomposition, and control electronic and steric effects for modulating catalysis, the anionic (X) ligands help balance the charge and often get involved in catalytic cycles by ligand exchange with substrates .…”

Section: Introductionmentioning

confidence: 99%

N-Heterocyclic Carbene-Stabilized Gold Nanoclusters with Organometallic Motifs for Promoting Catalysis

Shen

Malola

et al. 2022

J. Am. Chem. Soc.

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The complexity of heterogeneous metal catalysts makes it challenging to gain insights into their catalytic mechanisms. Thus, there exists a huge gap between heterogeneous catalysis and organometallic catalysis. With the success in the preparation of highly robust atomically precise metal nanocluster catalysts (i.e., [Au16(NHC-1)5(PA)3Br2]3+ and [Au17(NHC-1)4(PA)4Br4]+, where NHC-1 is a bidentate NHC ligand, and PA is phenylacetylide) with surface organometallic motifs anchored on the metallic core, we demonstrate in this work how the metallic core works synergistically with the surface organometallic motifs to enhance the catalysis. More importantly, the discovery allows the development of highly stable and recyclable heterogeneous metal catalysts to achieve efficient hydroamination of alkynes with an extremely low catalyst dosage (0.002 mol %), helping bridge the gap between heterogeneous and homogeneous metal catalysis. The surface modification of metal nanocatalysts with organometallic motifs provides a new design principle of metal catalysts with enhanced catalysis.

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Section: Introductionmentioning

confidence: 99%

N-Heterocyclic Carbene-Stabilized Gold Nanoclusters with Organometallic Motifs for Promoting Catalysis

Shen

Malola

et al. 2022

J. Am. Chem. Soc.

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“…N-heterocyclic carbene ligands (NHCs) are increasingly used to modify the properties of nanoparticles and extended surfaces of inorganic materials. − These persistent carbenes form chemically and thermally robust and addressable adsorption layers on metals − and they can be used to tune catalytic ,, and electronic , properties. Rapid developments in the field are facilitated by the increasing availability of easily handled precursor salts that do not co-deposit strongly adsorbing counterions. , The great majority of the work on surfaces deals with the modification of coinage metals. − Considerably less attention has been given to Pt-group metals − and, to our knowledge, only Yoon et al described the grafting of an NHC to graphene.…”

Section: Introductionmentioning

confidence: 99%

Functionalization of Metal-Supported Graphene by an N-Heterocyclic Carbene

et al. 2022

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The functionalization of graphene (Gr) on Pt(111) and Ru(0001) substrates by an N-heterocyclic carbene (NHC) is described. The formation, thermal stability, and bonding geometry of the grafted NHC were probed using reflection absorption infrared spectroscopy (RAIRS). The carbene contains a CF3 substituent, which provides a set of three very strong absorption bands with which to monitor the chemical modification. By employing Pt(111) and Ru(0001) substrates, it is possible to compare markedly different graphene systems: while graphene forms a quasi-freestanding p-doped layer on Pt(111), its interaction with Ru(0001) involves periodic chemical bonding to form an n-doped layer. The RAIRS data show that the benzimidazolium hydrogen carbonate precursor transforms to a relatively strongly adsorbed NHC on both systems. Clean formation of the surface carbene at 300–350 K is attributed to a process activated by electron transfer from the supported graphene layer. The RAIRS signal attributed to the NHC on full-coverage Gr/Pt(111) is removed on heating to ∼450 K, while it disappears from Gr/Ru(0001) at ∼400 K. The difference in thermal stability is interpreted in terms of weaker bonding of the electron-donor NHC to the n-doped graphene layer on Ru(0001). This hypothesis is explored using oxygen intercalation to decouple graphene from Ru(0001) to form a p-doped layer. The study outlines a method to modify graphene and also reveals that vibrational spectra of an adsorbed NHC provide a highly sensitive method to probe and distinguish between different graphene-on-metal systems.

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“…Noble-metal nanomaterials in various forms, including nanoparticles, [1] nanoclusters, [2] self-assembled films, [3] and two-dimensional (2D) coordination polymers (CPs), [4] exhibit fascinating properties and thus have broad applicability in optoelectronics, catalysis, and sensing. Although these fields have been developing for decades, the unsatisfactory chemical stability of noble-metal-based nanomaterials has greatly impeded their practical applications in ambient and aqueous environments.…”

Section: Introductionmentioning

confidence: 99%

Ultrastable Anti‐Acid “Shield” in Layered Silver Coordination Polymers

Sun¹,

Xie²,

Zhang³

et al. 2022

Angewandte Chemie

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Surface passivation technology provides noble-metal materials with limited chemical stability, especially under highly acidic condition. To design effective strategy to enhance stability of noble-metal particles, an understanding of their surface anticorrosion mechanism at the atomic level is desirable by using twodimensional (2D) noble-metal coordination polymer (CP) as an ideal model for their interfacial region. With the protection of 2-thiobenzimidazole (TBI), we isolated two Ag-based 2D CPs, {Ag 14 (TBI) 12 X 2 } n (SÀ X, where S denotes sheet and X = Cl or Br). These compounds exhibited excellent chemical stability upon immersion in various common solvents, boiling water, boiling ethanol, 10 % hydrogen peroxide, concentrated acid (12 M HCl), and concentrated alkali (19 M NaOH). Systematic characterization and DFT analyses demonstrate that the superior stability of SÀ X was attributed to the hydrophobic organic shell and dynamic proton buffer layer acting as a double protective "shield".

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N-heterocyclic carbene coordinated metal nanoparticles and nanoclusters

Cited by 71 publications

References 208 publications

N-Heterocyclic Carbene-Stabilized Gold Nanoclusters with Organometallic Motifs for Promoting Catalysis

N-Heterocyclic Carbene-Stabilized Gold Nanoclusters with Organometallic Motifs for Promoting Catalysis

Functionalization of Metal-Supported Graphene by an N-Heterocyclic Carbene

Ultrastable Anti‐Acid “Shield” in Layered Silver Coordination Polymers

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