Ligand-Protected Golden Fullerene Au with Unprecedented Metal Coordination Number of 15.

A golden fullerene with a composition of [Au(PhP)(5-CF-Hpa)] (CFCOO) (5-CF-Hpa=5-trifluoropyridyl-2-amine) (Au) has been synthesized with pyridylamino and phosphine ligands as the protecting agents. Single crystal X-ray structural analysis reveals that the cluster has a D Au core, which can be depicted as a centered core-shell structure Au@Au@Au. The 41 Au atoms of the Au@Au core-shell can be derived from placing a gold atom in the center of each polygon of C (D).

Resistance of a PdAu(8e) Core to Growth in Collision-Induced Sequential Reductive Elimination of (C≡CR) from [PdAu(C≡CR)].

Previous studies have reported that [PdAu(PA)] (PA = 3,5-(CF)CHC≡C) with an icosahedral superatomic PdAu(8e) core underwent collision-induced sequential reductive elimination (CISRE) of 1,3-diyne (PA) ( 2020, 124, 19119). The most likely scenario after the CISRE of (PA) is the growth of the PdAu(8e) core via the fusion of the Au(0) atoms produced from the Au(PA) units on the core surface. Contrary to expectation, anion photoelectron spectroscopy and theoretical calculations regarding the CISRE products [PdAu(PA)] ( = 1-6) revealed that the electronically closed PdAu(8e) core does not grow to a single superatom with (8 + 2)e but assembles with Au(2e) units.

All-Calixarene-Protected Silver Nanocluster with All Silver Atoms in a Face-Centered Cubic Arrangement.

Tailoring the surface ligands of metal nanoclusters is important for engineering unique configurations of metal nanoclusters. Thiacalix[4]arene has found extensive applications in the construction of metal nanoclusters. In this investigation, we present the synthesis and characterization of the first all-calixarene-protected silver nanoclusters, [Ag(CHCN)][Ag(BTCA)] (, HBTCA = -butylthiacalix[4]arene).

Interplay of kernel shape and surface structure for NIR luminescence in atomically precise gold nanorods.

It is challenging to attain strong near-infrared (NIR) emissive gold nanoclusters. Here we show a rod-shaped cluster with the composition of [Au(p-MBT)(Hdppa)](SOCF) (1 for short, Hdppa is N,N-bis(diphenylphosphino)amine, p-MBT is 4-methylbenzenethiolate) has been synthesized. Single crystal X-ray structural analysis reveals that it has a rod-like face-centered cubic (fcc) Au kernel built from two interpenetrating bicapped cuboctahedral Au units.

Large Scale Synthesis of a Stable Prefunctionalized Silver Nanocluster.

Due to the stability issue, It is difficult to prepare a silver nanocluster bearing functional sites, especially at a large scale. We report the synthesis and structure of a stable silver nanocluster bearing multiple surface aldehyde groups [Ag(PhPO)(p-CHOPhC≡C)]SbF, which allows for postsynthesis modification such as surface functionalization through aldimine condensation to give homochiral clusters. Remarkably, the preparation of this cluster can be done in ~90 % high yield at gram scale, which facilitates further studies and potential applications.

'Passivated Precursor' Approach to All-Alkynyl-Protected Gold Nanoclusters and Total Structure Determination of Au.

A 'passivated precursor' approach is developed for the efficient synthesis and isolation of all-alkynyl-protected gold nanoclusters. Direct reduction of dpa-passivated precursor Au-dpa (Hdpa=2,2'-dipyridylamine) in one-pot under ambient conditions gives a series of clusters including Au(C≡CR) (R=-CH-2-F), Au(C≡CR), Au(C≡CR), Au(C≡CR), and Au(C≡CR). These clusters can be well separated via column chromatography.

A Cages-on-Cluster Structure Constructed by Post-Clustering Covalent Modifications and Guest-Enabled Stimuli-Responsive Luminescence.

A gold(I)-cluster-based twin-cage has been constructed by post-clustering covalent modification of a hexa-aldehyde cluster precursor with triaminotriethylamines. The cages-on-cluster structure has double cavities and four binding sites, which show site-discriminative binding for silver(I) and copper(I) guests. The guests in the tripodal hats affect the luminescence of the cluster: the tetra-silver(I) host-guest complex is weakly red-emissive, while the bis-copper(I)-bis-silver(I) one is non-emissive but is a stimuli-responsive supramolecule.

Near-unity NIR phosphorescent quantum yield from a room-temperature solvated metal nanocluster.

Metal nanoclusters have emerged as promising near-infrared (NIR)-emissive materials, but their room-temperature photoluminescence quantum yield (PLQY), especially in solution, is often low (<10%). We studied the photophysics of Au(BuPhC≡C) (Au) and its alloy counterpart AuCu(BuPhC≡C) (AuCu) (where Bu is -butyl and Ph is phenyl) and found that copper (Cu) doping suppressed the nonradiative decay (~60-fold less) and promoted intersystem crossing rate (~300-fold higher). The AuCu nanocluster exhibited >99% PLQY in deaerated solution at room temperature with an emission maximum at 720 nanometers tailing to 950 nanometers and 61% PLQY in the oxygen-saturated solution.

Heterometallic Au Ag Macrocyclic Cluster Templated by a Supramolecular Melamine Dimer.

The application of supramolecular templates in aligning atomically precise heterometal arrays is important for pursuing functional materials. Herein, we report that a bilayered supramolecular tri-deprotonated melamine dimer functions as an effective template in the construction of a heterometallic gold(I)-silver(I) macrocyclic cluster [μ -(C N H ) ] -Au Ag . X-ray single crystal structural analysis showed that a crown-like Au Ag macrocycle is aligned around two parallelly stacked μ -(C N H ) moieties hold together with π-π interactions.

Alkynyl-Protected Bimetallic Nanoclusters with a Hybrid Mackay Icosahedral Ag Cu Cl Kernel and an Octahedral Ag Cu Kernel.

A facile strategy that directly reduces alkynyl-silver precursors and copper salts for the synthesis of bimetallic nanoclusters using the weak reducing agent Ph SiH is demonstrated. Two alkynyl-protected concentric-shell nanoclusters, (Ph P) [Ag Cu (C≡CR) ] and (Ph P) [Ag Cu Cl(C≡CR) ] (Ag Cu and Ag Cu Cl, R=bis(trifluoromethyl)phenyl), were successfully obtained and characterized by single-crystal X-ray diffraction and electro-spray ionization mass spectrometry. For the first time, a hybrid 55-atom two-shell Mackay icosahedron was found in Ag Cu Cl, which is icosahedral M Cl instead of M .

Integration of Metal Catalysis and Organocatalysis in a Metal Nanocluster with Anchored Proline.

Chiral metal nanoclusters have recently been attracting great attention. It is challenging to realize asymmetric catalysis via atomically precise metal nanoclusters. Herein, we report the synthesis and total structure determination of chiral clusters [AuAg(dppf)(l-/d-proline)](BF) (-/d-Au).

Disc-Like Silver Nanocluster Ag Built with Bicapped Hexagonal Prismatic Ag and Ino Decahedral Ag Units.

The reduction of alkynyl-silver and phosphine-silver precursors with a weak reducing reagent Ph SiH led to the formation of a novel silver nanocluster [Ag (PPh ) (C≡CR) ] (R=4-CH OC H ), which is the largest structurally characterized cluster of clusters. This disc-shaped cluster has a Ag kernel consisting of a bicapped hexagonal prismatic Ag unit wrapped by six Ino decahedra through edge-sharing. This is the first time that Ino decahedra are used as a building block to assemble a cluster of clusters.

Face-Centered Cubic Silver Nanoclusters Consolidated with Tetradentate Formamidinate Ligands.

Growing attention has been paid to nanoclusters with face-centered cubic (fcc) metal kernels, due to its structural similarity to bulk metals. We demonstrate that the use of tetradentate formamidinate ligands facilitate the construction of two fcc silver nanoclusters: [Ag(5-F-dpf)Cl](SbF) (, 5-F-Hdpf = ,'-di(5-fluoro-2-pyridinyl)formamidine) and [Ag(5-Me-dpf)](NO) (, 5-Me-Hdpf = ,'-di(5-methyl-2-pyridinyl)formamidine). Single-crystal X-ray structural analysis revealed that the silver atoms in both clusters are in a layer-by-layer arrangement, which can be viewed as a portion of the fcc packing of silver.

Structural Engineering toward Gold Nanocluster Catalysis.

Atomically precise gold nanoclusters provide great opportunities to explore the relationship between the structure and properties of nanogold catalysts. A nanocluster consists of a metal core and a surface ligand shell, and both the core and shell have significant effects on the catalytic properties. Thanks to their precise structures, the active metal site of the clusters can be readily identified and the effects of ligands on catalysis can be disclosed.

Identification of the Active Species in Bimetallic Cluster Catalyzed Hydrogenation.

Identification of the authentic active species of cluster catalysis is rather challenging, and direct structural evidence is quite valuable and difficult to obtain. Two "isostructural" clusters, AgCuCl(dppb)(PhC≡C)(SOCF) () and AgCuClH(dppb)(PhC≡C)(SOCF) () (dppb is 1,4-bis(diphenylphosphine)butane), have been successfully isolated and structurally characterized. Both these clusters have a centered icosahedron Ag core with the same peripheral composition and structure.

Site-specific doping of silver atoms into a Au nanocluster as directed by ligand binding preferences.

For the first time site-specific doping of silver into a spherical Au nanocluster has been achieved in [AuAg(MeOPhS)(PPh)] (BF) (AuAg) through a dual-ligand coordination strategy. Single crystal X-ray structural analysis shows that the cluster has a distorted centered icosahedral Au@AuAg core of symmetry, in contrast to the Au@Au kernel in the well-known [Au(SR)] (R = CHCHPh). An interesting feature is the coexistence of [Au(SPhOMe)] dimeric staples and [P-Au-SPhOMe] semi-staples in the title cluster, due to the incorporation of PPh.

Structural transformation and catalytic hydrogenation activity of amidinate-protected copper hydride clusters.

Copper hydrides are important hydrogenation catalysts, but their poor stability hinders the practical applications. Ligand engineering is an effective strategy to tackle this issue. An amidinate ligand, N,N'-Di(5-trifluoromethyl-2-pyridyl)formamidinate (Tf-dpf) with four N-donors has been applied as a protecting agent in the synthesis of stable copper hydride clusters: CuH(Tf-dpf)(OAc) (Cu) with three interfacial μ-H and [CuH(Tf-dpf)(OAc)]·OAc (Cu) with three interstitial μ-H.

Anion-Directed Regulation of Structures and Luminescence of Heterometallic Clusters.

Anions have been used to regulate the structures and luminescence of heterometallic clusters. Introducing ClO into orange-emissive, butterfly-like [(C)(Au-PPhpy ) Ag ](BF ) (1, PPhpy =bis(2-pyridyl)phenylphosphine) leads to the formation of red-emissive [(C)(Au-PPhpy ) Ag (ClO ) ](ClO ) (2) with a novel trigonal bipyramidal structure; employing PhCO gives yellow-emissive, hexagram-like [(C)(Au-PPhpy ) Ag (PhCO ) ](BF ) (3). Notably, 1 exhibits weak luminescence in CH Cl /CH OH=1 : 1 (v : v) with a quantum yield (QY) of 0.

Nitrogen Donor Protection for Atomically Precise Metal Nanoclusters.

Surface organic ligands are critical in dictating the structures and properties of atomically precise metal nanoclusters. In contrast to the conventionally used thiolate, phosphine and alkynyl ligands, nitrogen donor ligands have not been used in the protection for well-defined metal nanoclusters until recently. This review focuses on recent developments in atomically precise metal nanoclusters stabilized by different types of nitrogen donor ligands, in which the synthesis, total structure determination and various properties are covered.

Ligand Engineering toward the Trade-Off between Stability and Activity in Cluster Catalysis.

We report the structures, stability and catalysis properties of two Ag nanoclusters, namely [Ag (H BTCA) (O PPh ) ]SbF (1) and [Ag (C≡CC H -3,5-R ) (O PPh ) ]SbF (2) (H BTCA=p-tert-butylthiacalix[4]arene, R=OMe). Both Ag structures possess an identical icosahedral kernel that is surrounded by eight peripheral Ag atoms. Single-crystal structural analysis and ESI-MS revealed that 1 is an 8-electron cluster and 2 has four free electrons.

A 59-Electron Non-Magic-Number Gold Nanocluster Au(C≡CR) Showing Unexpectedly High Stability.

An atomically resolved gold nanocluster Au(C≡CCH-2,4-F) () with an unusual 59 valence electrons has been synthesized. Single-crystal X-ray diffraction reveals that its Au kernel is a Au Marks decahedron capped by two Au units. The surface structure of consists of 20 linear Au(C≡CR) staples.

Superatomic Orbital Splitting in Coinage Metal Nanoclusters.

The superatomic orbital splitting (SOS) method is developed to understand the electronic structures of coinage metal nanoclusters, in which delocalized electron counts are not magic numbers. Because the symmetry of a metal core can significantly affect the electronic structure of a nanocluster, this method takes the shape of the core into account in determining the order of group orbital levels. By taking nanoclusters as superatoms, a highly positively charged core is established by removing the ligands and staples.

Molecular Gold Nanocluster Au Showing Metallic Electron Dynamics.

The boundary between molecular and metallic gold nanoclusters is of special interest. The difficulty in obtaining atomically precise nanoclusters larger than 2 nm limits the determination of such a boundary. The synthesis and total structural determination of the largest all-alkynyl-protected gold nanocluster (PhP)[Au(C≡CR)] (R = 4-CFCH-) () are reported.

Rod-Shaped Silver Supercluster Unveiling Strong Electron Coupling between Substituent Icosahedral Units.

The first linear silver supercluster based on icosahedral Ag units has been constructed via bridging of dpa ligands: Ag(dpa)(SbF) (Hdpa = dipyridylamine) (). Single-crystal X-ray diffraction reveals that this rod-shaped cluster consists of four vertex-sharing Ag icosahedra in a linear arrangement. This cluster represents the longest one-dimensional metal nanocluster with a resolved structure.

Ligand-Protected Au with a Novel Structure and Remarkable CO Electroreduction Performance.

A Au nanocluster with the composition of [Au (p-MBT) (Ph P) ](SbF ) (p-MBT=4-methylbenzenethiolate) is synthesized via direct reduction of gold-phosphine and gold-thiolate precursors. Single-crystal X-ray diffraction reveals that this Au nanocluster features a face-centered cubic (fcc) Au kernel, different from the well-known two-shell cuboctahedral arrangement in Au (Ph P) Cl . The Au cluster shows a wide optical absorption band with optical energy gap (E =1.