Self-assembly of an unprecedented polyoxomolybdate anion [Mo20O66]12- in a giant peanut-like 62-core silver-thiolate nanocluster

A 66-Nuclear All-Alkynyl Protected Peanut-Shaped Silver(I)/Copper(I) Heterometallic Nanocluster: Intermediate in Copper-Catalyzed Alkyne-Azide Cycloaddition

Ligand-protected heterometallic nanoclusters in contrast to homo-metal counterparts show more broad applications due to the synergistic effect of hetero-metals but their controllable syntheses remain a challenge. Among heterometallic nanoclusters, monovalent Ag-Cu compounds are rarely explored due to much difference of Ag(I) and Cu(I) such as atom radius, coordination habits, and redox potential. Encouraged by copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction, comproportionation reaction of Cu(II)X2 and Cu(0) in the presence of (PhC≡CAg)n complex and molybdate generated a core-shell peanut-shaped 66-nuclear Ag(I)-Cu(I) heterometallic nanocluster, [(Mo4O16)2@Cu12Ag54(PhC≡C)50] (referred to as Ag54Cu12). The structure and composition of Ag-Cu heterometallic nanocluster are fully characterized. X-ray single crystal diffraction reveals that Ag54Cu12 has a peanut-shaped silver(I)/copper(I) heterometallic nanocage protected by fifty phenylacetylene ligands in µ3-modes and encapsulated two mutually twisted tetramolybdates. Heterometallic nanocage contains a 54-Ag-atom outer ellipsoid silver cage decorated by 12 copper inside wall. Nanosized Ag54Cu12 is a n-type narrow-band-gap semiconductor with a good photocurrent response. Preliminary experiments demonstrates that Ag54Cu12 itself and activated carbon supported Ag54Cu12/C are effective catalysts for 1,3-dipole cycloaddition between alkynes and azides at ambient conditions. The work provides not only a new synthetic route toward Ag(I)-Cu(I) nanoclusters but also an important heterometallic intermediate in CuAAC catalytic reaction.

Two structurally new Lindqvist hexaniobate-templated silver thiolate clusters

Two structurally new Lindqvist hexaniobate-templated silver thiolate clusters, [Nb6O19@Ag45(iPrS)23(CH3COO)14] (Ag45) and (H3O)4[Nb6O19@Ag41KS2.5O2(H2O)7.5(iPrS)24(CH3COO)5] (Ag41), were synthesized using a facile one-pot solvothermal approach. Single crystal X-ray diffraction analyses revealed the presence of a classical Lindqvist-type [Nb6O19]8- anion template, with iPrS- and CH3COO- surface-protecting ligands in both silver clusters, which can further form two-dimensional Ag45 assembly and one-dimensional Ag41 chain packing structures. Both Ag45 and Ag41 clusters exhibited intriguing photothermal conversion properties and temperature-dependent emission behavior.

Atomically Precise Silver Clusters Stabilized by Lacunary Polyoxometalates with Photocatalytic CO2 Reduction Activity

The syntheses of atomically precise silver (Ag) clusters stabilized by multidentate lacunary polyoxometalate (POM) ligands have been emerging as a promising but challenging research direction, the combination of redox-active POM ligands and silver clusters will render them unexpected geometric structures and catalytic properties. Herein, we report the successful construction of two structurally-new lacunary POM-stabilized Ag clusters, TBA6 H14 Ag14 (DPPB)4 (CH3 CN)9 [Ag24 (Si2 W18 O66 )3 ] ⋅ 10CH3 CN ⋅ 9H2 O ({Ag24 (Si2 W18 O66 )3 }, TBA=tetra-n-butylammonium, DPPB=1,4-Bis(diphenylphosphino)butane) and TBA14 H6 Ag9 Na2 (H2 O)9 [Ag27 (Si2 W18 O66 )3 ] ⋅ 8CH3 CN ⋅ 10H2 O ({Ag27 (Si2 W18 O66 )3 }), using a facile one-pot solvothermal approach. Under otherwise identical synthetic conditions, the molecular structures of two POM-stabilized Ag clusters could be readily tuned by the addition of different organic ligands. In both compounds, the central trefoil-propeller-shaped {Ag24 }14+ and {Ag27 }17+ clusters bearing 10 delocalized valence electrons are stabilized by three C-shaped {Si2 W18 O66 } units. The femtosecond/nanosecond transient absorption spectroscopy revealed the rapid charge transfer between {Ag24 }14+ core and {Si2 W18 O66 } ligands. Both compounds have been pioneeringly investigated as catalysts for photocatalytic CO2 reduction to HCOOH with a high selectivity.

Three in One: Three Different Molybdates Trapped in a Thiacalix[4]arene Protected Ag72 Nanocluster for Structural Transformation and Photothermal Conversion

Polyoxometalates (POMs) represent crucial intermediates in the formation of insoluble metal oxides from soluble metal ions, however, the rapid hydrolysis-condensation kinetics of MoVI or WVI makes the direct characterization of coexisted molecular species in a given medium extremely difficult. Silver nanoclusters have shown versatile capacity to encapsulate diverse POMs, which provides an alternative scene to appreciate landscape of POMs in atomic precision. Here, we report a thiacalix[4]arene protected silver nanocluster (Ag72b) that simultaneously encapsulates three kinds of molybdates (MoO4 2- , Mo6 O22 8- and Mo7 O25 8- ) in situ transformed from classic Lindqvist Mo6 O19 2- , providing more deep understanding on the structural diversity and condensation growth route of POMs in solution. Ag72b is the first silver nanocluster trapping so many kinds of molybdates, which in turn exert collective template effect to aggregate silver atoms into a nanocluster. The post-reaction of Ag72b with AgOAc or PhCOOAg produces a discrete Ag24 nanocluster (Ag24a) or an Ag28 nanocluster based 1D chain structure (Ag28a), respectively. Moreover, the post-synthesized Ag28a can be utilized as potential ignition material for further application. This work not only provides an important model for unlocking dynamic features of POMs at atom-precise level but also pioneers a promising approach to synthesize silver nanoclusters from known to unknown.

Exploring amine-rich supramolecular silver(I) metallogels for autonomous self-healing and as catalysts for a three component coupling reaction

A series of Ag(I) supramolecular organo-aqueous gels have been synthesized in the presence of an amine-rich triazole ligand as a gelator. Judicious choice of the triazole derivative and counter anion allows a desired spatial orientation of the pendant amine functionality to accentuate the gelation ability and autonomous self-healability via hydrogen bonding. In addition, the hydrogen bond donors, i.e. pendant -NH2 groups, offer a critical proximity of counter anions to the Lewis acidic Ag(I) and the reactants for promoting a three component coupling reaction of an aldehyde, a terminal alkyne and an amine, giving expedient access to propargyl amines, with remarkable functional group tolerance for both aromatic and aliphatic aldehydes, and aryl acetylenes. Experiments substantiate the pivotal role of counter anions and H-bonding interactions in the observed preference for propargylamines over the diacetylene by-product. Our catalyst is robust, bench-stable, and recyclable, and demonstrates a catalytic efficiency comparable to or better than those of reported systems. The catalyst was found equally effective for the gram-scale synthesis of propargylamines. Our approach lies at the intersection of metal-based, H-bond-mediated counter anion-tuned catalysis, evincing a potential for the development of purpose-built supramolecular gels for desired catalytic applications in the future.

Anion-templated silver nanoclusters: precise synthesis and geometric structure

Metal nanoclusters (NCs) are gaining much attention in nanoscale materials research because they exhibit size-specific physicochemical properties that are not observed in the corresponding bulk metals. Among them, silver (Ag) NCs can be precisely synthesized not only as pure Ag NCs but also as anion-templated Ag NCs. For anion-templated Ag NCs, we can expect the following capabilities: 1) size and shape control by regulating the central anion (anion template); 2) stabilization by adjusting the charge interaction between the central anion and surrounding Ag atoms; and 3) functionalization by selecting the type of central anion. In this review, we summarize the synthesis methods and influences of the central anion on the geometric structure of anion-templated Ag NCs, which include halide ions, chalcogenide ions, oxoanions, polyoxometalate, or hydride/deuteride as the central anion. This summary provides a reference for the current state of anion-templated Ag NCs, which may promote the development of anion-templated Ag NCs with novel geometric structures and physicochemical properties.

Solvent-Controlled Condensation of [Mo2 O5 (PTC4A)2 ]6- Metalloligand in Stepwise Assembly of Hexagonal and Rectangular Ag18 Nanoclusters

Stepwise assembly starting from a preassembled metalloligand is a promising approach to obtain otherwise unattainable silver nanoclusters, but hard to be intrinsically identified due to the lack of convincing evidence to justify such a process. Herein, hexagonal and rectangular Ag₁₈ nanoclusters are constructed from the [Mo₂ O₅ (PTC4A)₂ ]^6- (H₄ PTC4A=p-phenyl-thiacalix[4]arene) metalloligand through stepwise assembly. The formation of the metalloligand is confirmed by electrospray ionization mass spectrometry, then assembled with silver ions to form two geometrically different Ag₁₈ nanoclusters in different solvents. The cyclization from the metalloligand to [(Mo₂ O₅ PTC4A)₆ ]^12- can be realized without alcohols and otherwise blocked by them. The installation of this metalloligand not only provides comprehensive understanding of how the solvents regulate the silver nanocluster structures, but also brings new insights for the controllable ligand metallization and subsequent condensation.

In situ insertion of copper to form heteroanionic D3h-symmetric [Cu3Mo8O32]10- for a templated Ag55 nanocluster

A polyoxometalate-templated thiolate-protected silver nanocluster, [Cu₃(Mo₄O₁₆)₂@Ag₅₅(CyhS)₄₃(CH₃O)(COOCF₃)]·3H₂O, has been isolated under solvothermal conditions. In situ insertion of three Cu²⁺ ions into two polymolybdate anions generated a new, sandwich-type D_3h-symmetric [Cu₃(Mo₄O₁₆)₂]^10- polyoxoanion template encapsulated into an Ag₅₅(CyhS)₄₃ shell. The structure and composition of this Ag nanocluster have been fully characterized. This work has provided a new way to develop high-nuclearity metal nanoclusters with various structures.

Stepwise Assembly of Ag42 Nanocalices Based on a MoVI-Anchored Thiacalix[4]arene Metalloligand

Metalloligand strategy has been well recognized in the syntheses of heterometallic coordination polymers; however, such a strategy used in the assembly of silver nanoclusters is not broadly available. Herein, we report the stepwise syntheses of a family of halogen-templated Ag₄₂ nanoclusters (Ag42c-Ag42f) based on Mo^VI-anchored p-tert-butylthiacalix[4]arene (H₄TC4A) as a metalloligand (hereafter named MoO₃-TC4A). X-ray crystallography demonstrates that they are similar C₃-symmetric silver-organic nanocalices capped by six MoO₃-TC4A metalloligands, which are evenly distributed up and down the base of 42 silver atoms. These nanoclusters can be disassembled to six bowl-shaped [Ag₁₁(MoO₃-TC4A)(RS)₃] secondary building units (SBUs, R = Et or ⁿPr), which are fused together in a face-sharing fashion surrounding Cl^- or Br^- as a central anion template. The electrospray mass spectrometry (ESI-MS) indicates their high stabilities in solution and verifies the formation of the MoO₃-TC4A metalloligand, thereby rationalizing the overall stepwise assembly process for them. Moreover, Ag42c shows lower cytotoxicity and better activity against the HepG-2 cell line than MCF-7 and BGC-823. These results not only exemplify the effectiveness of a thiacalix[4]arene-based metalloligand in the assembly of silver nanoclusters but also give us profound insight about the step-by-step assembly process in silver nanoclusters.

Trapping a [W10O32]6- decatungstate anion in an Ag44 nanowheel

Compound [Ag 44 (W 10 O 32 )(S t Bu) 24 (CF 3 COO) 8 ](CF 3 COO) 6 ·6H 2 O ( 1 ) was synthesized through the one-pot method, which is the first case of isolating a new silver thiolate cluster containing a [W 10 O 32 ] 6- template which transforms from WO 4 2- polyoxoanion through a self-assembly process. The anionic nature of the reduced [W 10 O 32 ] 6- template and the effective silver-oxygen interaction contribute to the formation of the Ag 44 nanowheel in 1 . The luminescence, photocatalytic activity and electrochemistry properties of 1 were studied.

Master key to coinage metal nanoclusters treasure chest: 38-metal clusters

Atomically precise metal nanoclusters with specific chemical compositions have become a popular research topic due to their precise structures, attractive properties, and wide range of applications in various fields. Currently, among more than 100 reported metal nanoclusters with precise formulas, 38-atom coinage metal nanoclusters stand out due to their unique structural diversities, such as face-centered cubic (FCC) and body-centered cubic (BCC) arrangements. Among them, the formation of the metal cores includes vertex-sharing, face-fusion, and FCC cubes fusion. Due to their geometrical features, 38-atom coinage metal nanoclusters exhibit attractive properties, making them an ideal model for exploring structure-property relationships. Therefore, 38-atom coinage metal nanoclusters are a universal key to the treasure trove of nanoclusters, which can open almost all fields and are of great research significance. This paper focuses on the structure of 38-atom coinage metal nanoclusters and reviews the preparation and crystallization methods, excellent properties, and practical applications. Finally, future research prospects and development opportunities are provided.

Protection of Ag Clusters by Metal-Oxo Modules

Monodisperse and atomically precise Ag nanoclusters have attracted considerable recent research interest. A conventional silver cluster usually consists of a silver metallic kernel and an organic peripheral ligand shell. Nevertheless, the present inevitable problem is the unsatisfied stability of such nanoclusters. In this concept, we will give an introduction to Ag clusters protected by metal-oxo modules which exhibit enhanced stability and unique properties. Accordingly, three different types of clusters are summarized: (1) Ag clusters protected by mononuclear oxometallates; (2) Ag clusters protected by block-like metal-oxo clusters; (3) Ag clusters protected by hollow-like metal-oxo clusters. The aim of this concept is to offer possible general guidance and insight into future rational design of more metal-oxo clusters protected silver clusters or even other coinage metal nanoclusters.

[Ag9(1,2-BDT)6]3-: How Square-Pyramidal Building Blocks Self-Assemble into the Smallest Silver Nanocluster

The emerging promise of few-atom metal catalysts has driven the need for developing metal nanoclusters (NCs) with ultrasmall core size. However, the preparation of metal NCs with single-digit metallic atoms and atomic precision is a major challenge for materials chemists, particularly for Ag, where the structure of such NCs remains unknown. In this study, we developed a shape-controlled synthesis strategy based on an isomeric dithiol ligand to yield the smallest crystallized Ag NC to date: [Ag9(1,2-BDT)6]3- (1,2-BDT = 1,2-benzenedithiolate). The NC's crystal structure reveals the self-assembly of two Ag square pyramids through preferential pyramidal vertex sharing of a single metallic Ag atom, while all other Ag atoms are incorporated in a motif with thiolate ligands, resulting in an elongated body-centered Ag9 skeleton. Steric hindrance and arrangement of the dithiolated ligands on the surface favor the formation of an anisotropic shape. Time-dependent density functional theory based calculations reproduce the experimental optical absorption features and identify the molecular orbitals responsible for the electronic transitions. Our findings will open new avenues for the design of novel single-digit metal NCs with directional self-assembled building blocks.

Controlling the Crystallographic Packing Modes of Pt1Ag28 Nanoclusters: Effects on the Optical Properties and Nitrogen Adsorption-Desorption Performances

We herein report the manipulation of the crystallographic packing modes of Pt₁Ag₂₈(S-Adm)₁₈(PPh₃)₄ nanoclusters by altering counterions as different polyoxometalates (POMs). Specifically, the Cl^- anion of the presynthesized Pt₁Ag₂₈ nanocluster was substituted by POM anions including [Mo₆O₁₉]^2-, [W₆O₁₉]^2-, or [PW₁₂O₄₀]^3-. The crystal lattices of these Pt₁Ag₂₈ nanoclusters with diverse anions showed distinct packing modes and thus manifested remarkably distinguishable crystalline-state optical properties and nitrogen adsorption-desorption performances. Overall, the combination of intercluster control in this work and intracluster control reported previously (the control over metal-ligand within the nanocluster framework) accomplished a more comprehensive manipulation over the M₂₉(SR)₁₈(PR'₃)₄ nanocluster system, which enables us to further grasp the structure-property correlations at the atomic level.

Progress in controlling the synthesis of atomically precise silver nanoclusters

This short review was designed to summarize the advances in synthesis methods of silver nanoclusters.

A construction guide for high-nuclearity (≥50 metal atoms) coinage metal clusters at the nanoscale: bridging molecular precise constructs with the bulk material phase

Synthesis remains a major strength in chemistry and materials science and relies on the formation of new molecules and diverse forms of matter. The construction and identification of large molecules poses specific challenges and has historically lain in the realm of biological (organic)-type molecules with evolved synthesis methods to support such endeavours. But with the development of analytical tools such as X-ray crystallography, new synthesis methods toward large metal-based (inorganic) molecules and clusters have come to the fore, making it possible to accurately determine the precise distribution of hundreds of atoms in large clusters. In this review, we focus on different synthesis protocols used to form new metal clusters such as templating, alloying and size-focusing strategies. A specific focus is on group 11 metals (Cu, Ag, Au) as they currently predominate large metal cluster investigations and related Au and Ag bulk surface phenomena. This review focuses on metal clusters that have very high-nuclearity, i.e. with 50 or more metal centers within the isolated cluster. This size domain, it is believed, will become increasingly important for a variety of applications as these metal clusters are positioned at the interface between the molecular and bulk phases, whilst remaining a classic nanomaterial and retaining unique nano-sized properties.

tert-Butyl thiol and pyridine ligand co-protected 50-nuclei clusters: the effect of pyridines on Ag-SR bonds

Constructing silver(i)-thiolate clusters from simple building blocks usually involves elusive self-assembly processes and remains a long-standing challenge. In this work, we report 6 silver(i)-thiolate clusters protected by pyridines, namely, [Ag3(tBuS)2(Py)(NO3)]n (Py = pyridine) (1), [Ag10(tBuS)6(Py)6(CF3CO2)4]·3Py (2), [Ag12(iPrS)6(Py)8(NO3)6]·2H2O (3), Ag12(iPrS)6(Py)8(CF3CO2)6 (4), Ag12(iPrS)6(4-ap)6(NO3)6 (4-ap = 4-aminopyridine) (5), and [Ag50S13(tBuS)20(Py)12]·4BF4·4Py·4CH3OH·2H2O (6). Single-crystal X-ray crystallography analysis reveals that six clusters are constructed by four types of structural blocks, including the PyAg(tBuS)2 monomer, Py2Ag2(tBuS)2 dimer, Py3Ag3(tBuS)3 trimer and (4-ap)6Ag6(iPrS)6 hexamer. Notably, cluster 6 consists of a rhombic dodecahedron S@Ag14 kernel with 12 interstitial S2- atoms encapsulated by 8 μ4-tBuS- ligands, as well as six unique butterfly-like (Py)2Ag6(tBuS)2 staple motifs composed of a Py2Ag2(tBuS)2 dimer and four silver ions. Moreover, it is found that pyridine ligands have important influence on the construction of silver thiolate clusters and their Ag-SR bond lengths.

Synthesis and characterization of a nanocluster-based silver(i) tert-butylethynide compound with a large second-harmonic generation response

A new nanocluster-based silver(i) tert-butylethynide compound, namely, (tBuC[triple bond, length as m-dash]CAg)2(Ag4SiW12O40)(DMSO)6 (HT-1), has been synthesized and structurally characterized by X-ray crystallography. The two kinds of nanocluster synthons (a silver aggregate named [(tBuC[triple bond, length as m-dash]C)2Ag6(DMSO)6] and a SiW12 polyoxoanion) are assembled into a three-dimensional coordination network, which has a non-centrosymmetric crystal lattice. Powder second-harmonic generation (SHG) measurements reveal that HT-1 belongs to the phase-matchable class with a moderately strong SHG response of about 3 times that of the KH2PO4 (KDP) sample. HT-1 represents the first example of a Ag(i) alkynyl cluster compound with a SHG response. The present study not only extends the application fields of Ag(i) alkynyl clusters but also demonstrates a new paradigm for understanding the Ag(i) alkynyl structural chemistry.

Self-assembly of thiolate-protected silver coordination polymers regulated by POMs

Two polyoxometalate (POM)-based thiolate-protected silver coordination polymers were obtained using different Lindquist-type POM precursors under the same conditions. [Ag10(StBu)6(CH3CN)8(Mo6O19)2·2CH3CN]n (abbreviated as Ag10-Mo6) was observed to feature chain-like structures containing Ag10 clusters linked by [Mo6O19]2- anions through Ag-O bonds and to exhibit unprecedented green photoluminescence at room temperature. Interestingly, [Ag18(StBu)12(CH3CN)5(Mo6O19)2·Mo6O19·2CH3CN]n (abbreviated as Ag18-Mo6) was found to contain 20-membered cycle-Ag10S10 each with a diameter of approximately 11.382 Å and constructed from alternating silver and sulfur atoms and interconnected into an elegant Ag-S sheet by interstitial the Ag3StBu and AgCH3CN motifs, and to also contain [Mo6O19]2- counter ions filling in the spaces made by the cycle-Ag10S10 and strengthening the structure by forming Ag-O bonds. Such a stacking structure for thiolate-protected silver compounds has not been previously reported.

A Polyoxochromate Templated 56-Nuclei Silver Nanocluster

Most of polyoxometallates (POMs) templated silver nanoclusters recorded so far are polyoxomolybdates and polyoxotungstates; however, as congeneric polyoxochromates, they are rarely observed in silver nanoclusters. Herein, a high-nuclearity polyoxochromate, (Cr^III₄Cr^VI₈O₃₆)^12-, is uncovered in a novel silver nanocluster (SD/Ag56a) as an anion template. The mixed-valent (Cr^III₄Cr^VI₈O₃₆)^12- consists of four edge-sharing Cr^IIIO₆ octahedra and eight Cr^VIO₄ tetrahedra, which are fused together by sharing one or two vertexes. The (Cr^III₄Cr^VI₈O₃₆)^12- is the by far highest nuclearity polyoxochromate and is trapped by outer Ag₅₆ bracelet-like shell coprotected by quaternary ligands including ⁱPrS^-, NapCOO^- (2-naphthalenecarboxylate), CF₃COO^-, and CH₃CN. The antiferromagnetic property and solution behavior of SD/Ag56a are discussed in detail.

A stably discrete 31-nuclearity silver(i) thiolate nanocluster luminescent thermometer supported by DMF auxiliary ligands

The stably discrete [Ag₃₁S₃(S^tBu)₁₇(CF₃COO)₇(CO₃)_0.5(CF₃COOH)_0.5(DMF)₄] nanocluster in Ag31S20-DMF (1) shaped in a turtle-like structure exhibits temperature-sensitive luminescence properties.

Silver clusters templated by homo- and hetero-anions

This article highlights the use of homo- and hetero-anion templates for the ordered assembly of high-nuclearity silver clusters.

Core-dependent properties of copper nanoclusters: valence-pure nanoclusters as NIR TADF emitters and mixed-valence ones as semiconductors

While valence-pure copper alkynyl nanoclusters show near-infrared TADF, the mixed-valence ones exhibit semiconductivity.

We report herein that copper alkynyl nanoclusters show metal-core dependent properties via a charge-transfer mechanism, which enables new understanding of their structure–property relationship. Initially, nanoclusters 1 and 2 bearing respective Cu(i)₁₅ (C1) and Cu(i)₂₈ (C2) cores were prepared and revealed to display near-infrared (NIR) photoluminescence mainly from the mixed alkynyl → Cu(i) ligand-to-metal charge transfer (LMCT) and cluster-centered transition, and they further exhibit thermally activated delayed fluorescence (TADF). Subsequently, a vanadate-induced oxidative approach to in situ generate a nucleating Cu(ii) cation led to assembly of 3 and 4 featuring respective [Cu(ii)O₆]@Cu(i)₄₇ (C3) and {[Cu(ii)O₄]·[VO₄]₂}@Cu(i)₄₆ (C4) cores. While interstitial occupancy of Cu(ii) triggers inter-valence charge-transfer (IVCT) from Cu(i) to Cu(ii) to quench the photoluminescence of 3 and 4, such a process facilitates charge mobility to render them semiconductive. Overall, metal-core modification results in an interplay between charge-transfer processes to switch TADF to semiconductivity, which underpins an unusual structure–property correlation for designed synthesis of metal nanoclusters with unique properties and functions.

Enclosing classical polyoxometallates in silver nanoclusters

Due to the elusive nature of polyoxometallates (POMs) in the assembly of silver clusters, POMs trapped by silver clusters are usually different from the pristine form, which surely increases the novelty of the assembly results but makes the final structure predictability challenging. Herein, three novel high-nuclearity silver-thiolate clusters trapping two kinds of classical POMs, Lindqvist-Mo6O192- and V10O286-, are reported. They are identified to be [(V10O28)@Ag44] (SD/Ag44a), [(V10O28)@Ag46] (SD/Ag46), and [(Mo6O19)@Ag44] (SD/Ag44b) clusters, which are further extended to 1D chain, 2D sql layer, and 3D pcu framework, respectively. Of note, SD/Ag44b contains a regular cubic Mo6O19 core sealed by an Ag44(EtS)24 shell in a pseudo-sodalite unit and six SCl4 planar squares connecting the respective adjacent silver tetragonal faces. This structure is a novel zeolite closely related to the natural alumino-silicate 'sodalite' but exceptionally made of core-shell silver clusters. Moreover, the Oh symmetric Mo6O192- templates an Oh symmetric Ag44 cluster in SD/Ag44b, realizing authentic symmetry delivery from guest to host in this system. This is a rare silver cluster family with classical POMs encapsulated.

Carboxylic acid stimulated silver shell isomerism in a triple core-shell Ag84 nanocluster

A unique triple core–shell Ag₈₄ nanocluster displaying isomerism, which is controlled by different carboxylic acids and a one-way transformation (SD/Ag84a and SD/Ag84b).

Isomerization is highly important in all aspects of science, yet it is rarely observed in nanoscience. Here, we synthesized a unique triple core–shell Ag₈₄ nanocluster displaying isomerism, which is controlled by different carboxylic acids and a one-way transformation (SD/Ag84a → SD/Ag84b). The innermost core is a rare Ag₁₀ nanocluster which comprises an Ag₆ octahedral unit as seen in face-centred cubic (fcc) silver metal and four capped Ag atoms. It templates two crescent-shaped polyoxometalate (W₇O₂₆)^10– shells which are then enclosed in a shell of silver shaped as rugby balls. The organic ligands (ⁱPrS^–, ⁿPrCOO^– and PhCOO^–) finally shield the metallic clusters. Due to slight differences in structure at two poles and the steric hindrance of ⁿPrCOO^– and PhCOO^–, SD/Ag84a and SD/Ag84b adopt the shapes of flat-headed and cuspidal prolate spheres, respectively. Interestingly, PhCOOH is dominant over ⁿPrCOOH whereby crystals of SD/Ag84b were isolated if PhCOOH is added during the synthesis of SD/Ag84a. This demonstrates that PhCOOH not only alters the organic coats but also induces metal shell re-organization. This work reveals carboxylate-controlled skeletal isomerism in silver nanoclusters for the first time, thus deepening the understanding of silver nanocluster assembly, flexibility and reactivity.

Investigating the influence of a CrO42−/Cr2O72− template in the formation of a series of silver–chalcogenide clusters

A series of silver–chalcogenide clusters was synthesised based on CrO₄²⁻/Cr₂O₇²⁻ anion templates.

Hierarchical multi-shell 66-nuclei silver nanoclusters trapping subvalent Ag6 kernels

Hierarchical nano structures are hard to fabircate. Here, we present three novel hierarchical multi-shell 66-nuclei silver nanoclusters, trapping ultrasmall Ag64+ nano-fragments by nine MoO42- ions. This Ag6@(MoO4)9 core is further wrapped by an outer Ag60 shell. The Ag6 kernel evolves from reduction involving DMF solvent. Carboxylate ligands are very important in the modulation of the polygon patterns on the Ag60 shell.

Photoluminescence modulation of an atomically precise silver(i)-thiolate cluster via site-specific surface engineering

A series of pyridyl ligand functionalized silver-thiolate nanoclusters with an identical cuboctahedron Ag12 core were prepared through site-specific surface engineering and fully characterized. Their wide-range photoluminescence modulation was systematically studied.

Unusual fcc-structured Ag10 kernels trapped in Ag70 nanoclusters

A bioctahedral Ag₁₀ kernel is locked by a pair of Mo₇O₂₆^10– anions to form an inner Ag₁₀@(Mo₇O₂₆)₂ core which is further encapsulated by an outer Ag₇₀ shell to form three-shell Ag₁₀@(Mo₇O₂₆)₂@Ag₇₀ nanoclusters.

Controlled trapping atom-precise ultrasmall silver nanoparticles into silver nanoclusters is challenging; thus only limited progress has been made in this area. We are therefore inspired to isolate two novel silver nanoclusters, Ag₁₀@Ag₇₀ (SD/Ag80a and SD/Ag80b; SD = SunDi), where a novel fcc-structured Ag₁₀ kernel built from two single-edge opened Ag₆ octahedra by sharing one edge is trapped. The bioctahedral Ag₁₀ kernel is locked by a pair of Mo₇O₂₆^10– anions to form an inner Ag₁₀@(Mo₇O₂₆)₂ core which is further encapsulated by an outer Ag₇₀ shell to form three-shell Ag₁₀@(Mo₇O₂₆)₂@Ag₇₀ nanoclusters. Notably, the bioctahedral Ag₁₀ kernel has not been observed in silver nanoclusters ever before, thus representing a new embryo state of silver nanoparticles. SD/Ag80a emits in the near infrared (NIR) region (λ_em = 730 nm) at low temperature. This work will deepen our understanding on the atomic-level growth of silver nanoparticles and complicated three-shell self-assembly involving polyoxometalate (POM) and two different silver nanoclusters.

Trapping an octahedral Ag6 kernel in a seven-fold symmetric Ag56 nanowheel

High-nuclearity silver clusters are appealing synthetic targets for their remarkable structures, but most are isolated serendipitously. We report here six giant silver-thiolate clusters mediated by solvents, which not only dictate the formation of an octahedral Ag₆⁴⁺ kernel, but also influence the in situ-generated Mo-based anion templates. The typical sevenfold symmetric silver nanowheels show a hierarchical cluster-in-cluster structure that comprises an outermost Ag₅₆ shell and an inner Ag₆⁴⁺ kernel in the centre with seven MoO₄^2- anion templates around it. Electrospray ionization mass spectrometry analyses reveal the underlying rule for the formation of such unique silver nanowheels. This work establishes a solvent-intervention approach to construct high-nuclearity silver clusters in which both the formation of octahedral Ag₆⁴⁺ kernel and in situ generation of various Mo-based anion templates can be simultaneously controlled.