Total Structure, Structural Transformation and Catalytic Hydrogenation of [Cu41 (SC6 H3 F2 )15 Cl3 (P(PhF)3 )6 (H)25 ]2- Constructed from Twisted Cu13 Units.

Herein, a remarkable achievement in the synthesis and characterization of an atomically precise copper-hydride nanocluster, [Cu41 (SC6 H3 F2 )15 Cl3 (P(PhF)3 )6 (H)25 ]2- via a mild one-pot reaction is presented. Through X-ray crystallography analysis, it is revealed that [Cu41 (SC6 H3 F2 )15 Cl3 (P(PhF)3 )6 (H)25 ]2- exhibits a unique shell-core-shell structure. The inner Cu29 kernel is composed of three twisted Cu13 units, connected through Cu4 face sharing. Surrounding the metal core, two Cu6 metal shells, resembling a protective sandwich structure are observed. This arrangement, along with intracluster π···π interactions and intercluster C─H···F─C interactions, contributes to the enhanced stability of [Cu41 (SC6 H3 F2 )15 Cl3 (P(PhF)3 )6 (H)25 ]2- . The presence, number, and location of hydrides within the nanocluster are established through a combination of experimental and density functional theory investigations. Notably, the addition of a phosphine ligand triggers a fascinating nanocluster-to-nanocluster transformation in [Cu41 (SC6 H3 F2 )15 Cl3 (P(PhF)3 )6 (H)25 ]2- , resulting in the generation of two nanoclusters, [Cu14 (SC6 H3 F2 )3 (PPh3 )8 H10 ]+ and [Cu13 (SC6 H3 F2 )3 (P(PhF)3 )7 H10 ]0 . Furthermore, it is demonstrated that [Cu41 (SC6 H3 F2 )15 Cl3 (P(PhF)3 )6 (H)25 ]2- exhibits catalytic activity in the hydrogenation of nitroarenes. This intriguing nanocluster provides a unique opportunity to explore the assembly of M13 units, similar to other coinage metal nanoclusters, and investigate the nanocluster-to-nanocluster transformation in phosphine and thiol ligand co-protected copper nanoclusters.

An insight, at the atomic level, into the structure and catalytic properties of the isomers of the Cu22 cluster.

The study of structural isomerism in copper nanoclusters has been relatively limited compared to that in gold and silver nanoclusters. In this work, we present the controlled synthesis and structures of two isomeric copper nanoclusters, denoted as Cu22-1 and Cu22-2, whose compositions were determined to be Cu22(SePh)10(Se)6(P(Ph-4F)3)8 through single-crystal X-ray diffraction (SCXRD). The structural isomerism of Cu22-1 and Cu22-2 arises from the different arrangements of a few Cu(SeR)(PR3) motifs on the surface structure. These subtle changes in the surface structure also influence the distortion of the core and the spatial arrangement of the clusters, and affect the electronic structure. Furthermore, due to their distinct structures, Cu22-1 and Cu22-2 exhibit different catalytic properties in the copper-catalyzed [3 + 2] azide-alkyne cycloaddition (CuAAC). Notably, Cu22-1 demonstrates efficient catalytic activity for photoinduced AAC, achieving a yield of 90% within 1 hour. This research contributes to the understanding of structural isomerism in copper nanoclusters and offers insights into the structure-function relationship in these systems.

An Initial Damage Model of Rock Materials under Uniaxial Compression Considering Loading Rates.

Existing rock material damage models always ignore the initial damage characteristics of rock materials, and the actual rock materials have initial damage characteristics. To consider the rock's initial damage characteristics, a series of compression tests for yellow sandstone was carried out. First, the acoustic emission characteristics and damage model of yellow sandstone, considering the loading rates, were analyzed. Second, an initial damage model, which can better describe the initial damage characteristics of yellow sandstone materials, is presented. The research results show that the strength and elastic modulus of yellow sandstone depends on the loading rate, and increases as the loading rate increases.

Structured copper-hydride nanoclusters provide insight into the surface-vacancy-defect to non-defect structural evolution.

Exploring the structural evolution of clusters with similar sizes and atom numbers induced by the removal or addition of a few atoms contributes to a deep understanding of structure-property relationships. Herein, three well-characterized copper-hydride nanoclusters that provide insight into the surface-vacancy-defect to non-defect structural evolution were reported. A surface-defective copper hydride nanocluster [Cu28(S-c-C6H11)18(PPh2Py)3H8]2+ (Cu28-PPh2Py for short) with only one C 1 symmetry axis was synthesized using a one-pot method under mild conditions, and its structure was determined. Through ligand regulation, a 29th copper atom was inserted into the surface vacancy site to give two non-defective copper hydride nanoclusters, namely [Cu29(SAdm)15Cl3(P(Ph-Cl)3)4H10]+ (Cu29-P(Ph-Cl)3 for short) with one C 3 symmetry axis and (Cu29(S-c-C6H11)18(P(Ph-pMe)3)4H10)+ (Cu29-P(Ph-Me)3 for short) with four C 3 symmetry axes. The optimized structures show that the 10 hydrides cap four triangular and all six square-planar structures of the cuboctahedral Cu13 core of Cu29-P(Ph-Me)3, while the 10 hydrides cap four triangular and six square-planar structures of the anti-cuboctahedral Cu13 core of Cu29-P(Ph-Cl)3, with the eight hydrides in Cu28-PPh2Py capping four triangular and four square planar-structures of its anti-cuboctahedral Cu13 core. Cluster stability was found to increase sequentially from Cu28-PPh2Py to Cu29-P(Ph-Cl)3 and then to Cu29-P(Ph-Me)3, which indicates that stability is affected by the overall structure of the cluster. Structural adjustments to the metal core, shell, and core-shell bonding model, in moving from Cu28-PPh2Py to Cu29-P(Ph-Cl)3 and then to Cu29-P(Ph-Me)3, enable the structural evolution and mechanism responsible for their physicochemical properties to be understood and provide valuable insight into the structures of surface vacancies in copper nanoclusters and structure-property relationships.

Regulation of Surface Structure of [Au9Ag12(SAdm)4(Dppm)6Cl6](SbF6)3 Nanocluster via Alloying.

Tailoring of specific sites on the nanocluster surface can tailor the properties of nanoclusters at the atomic level, for the in-depth understanding of structure and property relationship. In this work, we explore the regulation of surface structure of [Au9Ag12(SAdm)4(Dppm)6Cl6](SbF6)3 nanocluster via alloying. We successfully obtained the well-determined tri-metal [Au9Ag8@Cu4(SAdm)4(Dppm)6Cl6](SbF6)3 by the reaction of [Au9Ag12(SAdm)4(Dppm)6Cl6](SbF6)3 with the CuI(SAdm) complex precursor. X-ray crystallography identifies that the Cu dopants prioritily replace the position of the silver capped by Dppm ligand in the motif. The Cu doping has affected the optical properties of Au9Ag12 alloy nanocluster. DPV spectra, CD spectra and stability tests suggest that the regulation of surface structure via Cu alloying changes the electronic structure, thereby affecting the electrochemical properties, which provides insight into the regulation of surface structure of [Au9Ag12(SAdm)4(Dppm)6Cl6](SbF6)3 via alloying.

In situ studies on controlling an atomically-accurate formation process of gold nanoclusters.

Knowledge of the molecular formation mechanism of metal nanoclusters is essential for developing chemistry for accurate control over their synthesis. Herein, the "top-down" synthetic process of monodisperse Au13 nanoclusters via HCl etching of polydisperse Aun clusters (15 ≤ n ≤ 65) is traced by a combination of in situ X-ray/UV-vis absorption spectroscopy and time-dependent mass spectrometry. It is revealed experimentally that the HCl-induced synthesis of Au13 is achieved by accurately controlling the etching process with two distinctive steps, in sharp contrast to the traditional thiol-etching mechanism through release of the Au(i) complex. The first step involves the direct fragmentation of the initial larger Aun clusters into metastable intermediate Au8-Au13 smaller clusters. This is a critical step, which allows for the secondary size-growth step of the intermediates toward the atomically monodisperse Au13 clusters via incorporating the reactive Au(i)-Cl species in the solution. Such a secondary-growth pathway is further confirmed by the successful growth of Au13 through reaction of isolated Au11 clusters with AuClPPh3 in the HCl environment. This work addresses the importance of reaction intermediates in guiding the way towards controllable synthesis of metal nanoclusters.