High-Nuclearity Silver Ethynide Clusters Assembled with Phosphonate and Metavanadate Precursors

Chiral Ligand-Concentration Mediating Asymmetric Transformations of Silver Nanoclusters: NIR-II Circularly Polarized Phosphorescence Lighting

Near infrared (NIR) emitter with circularly polarized phosphorescence (CPP), known as NIR CPP, has emerged as a key part in the research of cutting-edge luminescent materials. However, it remains a challenge to obtain nanoclusters with NIR CPP activity. Here, we propose an asymmetric transformation approach to efficiently synthesize two pairs of chiral silver nanoclusters (R/S-Ag29 and R/S-Ag16) using an achiral Ag10 nanocluster as starting material in the presence of different concentration chiral inducer (R/S)-1,1'-binaphthyl-2,2'-diyl hydrogenphosphate (R/S-BNP). R/S-Ag29, formed in the low-concentration R/S-BNP, exhibits a unique kernel-shell structure consisting of a distorted Ag13 icosahedron and an integrated cage-like organometallic shell with a C3 symmetry, and possesses a superatomic 6-electron configuration (1S2|1P4). By contrast, R/S-Ag16, formed in the high-concentration R/S-BNP, features a sandwich-like pentagram with AgI-pure kernel. Profiting from the hierarchically chiral structures and superatomic kernel-dominated phosphorescence, R/S-Ag29 exhibits infrequent CPP activity in the second near-infrared (975 nm) region, being the first instance of NIR-II CPP observed among CPL-active metal nanoclusters. This study presents a new approach to reduce the difficulty of de novo synthesis for chiral silver nanomaterials, and facilitates the design of CPP-active superatomic nanoclusters in NIR region.

Thiacalix[4]arene-Protected Silver Nanoclusters Encapsulating Different Two-Electron Superatom Oligomers

The subvalent silver kernel represents the nascent state of silver cluster formation, yet the growth mechanism has long been elusive. Herein, two silver nanoclusters (Ag30 and Ag34) coprotected by TC4A4- (H4TC4A = p-tert-butylthiacalix[4]arene) and TBPMT- (TBPMTH = 4-tert-butylbenzenemethanethiol) containing 6e and 4e silver kernels are synthesized and characterized. The trimer of the 2e superatom Ag14 kernel in Ag30 is built from a central Ag6 octahedron sandwiched by two orthogonally oriented Ag5 trigonal bipyramids through sharing vertexes, whereas a double-octahedral Ag10 kernel in Ag34 is a dimer of 2e superatoms. They manifest disparate polyhedron fusion growth patterns at the beginning of the silver cluster formation. Their excellent solution stabilities are contributed by the multisite and multidentate coordination fashion of TC4A4- and the special valence electron structures. This work demonstrates the precise control of silver kernel growth by the solvent strategy and lays a foundation for silver nanocluster application in photothermal conversion.

Template-assisted synthesis of isomeric copper(i) clusters with tunable structures showing photophysical and electrochemical properties

A comparative study of structure-property relationships in isomeric and isostructural atomically precise clusters is an ideal approach to unravel their fundamental properties. Herein, seven high-nuclearity copper(i) alkynyl clusters utilizing template-assisted strategies were synthesized. Spherical Cu36 and Cu56 clusters are formed with a [M@(V/PO4)6] (M: Cu2+, Na+, K+) skeleton motif, while peanut-shaped Cu56 clusters feature four separate PO4 templates. Experiments and theoretical calculations suggested that the photophysical properties of these clusters are dependent on both the inner templates and outer phosphonate ligands. Phenyl and 1-naphthyl phosphate-protected clusters exhibited enhanced emission features attributed to numerous well-arranged intermolecular C-H⋯π interactions between the ligands. Moreover, the electrocatalytic CO2 reduction properties suggested that internal PO4 templates and external naphthyl groups could promote an increase in C2 products (C2H4 and C2H5OH). Our research provides new insight into the design and synthesis of multifunctional copper(i) clusters, and highlights the significance of atomic-level comparative studies of structure-property relationships.

A route to metalloligands consolidated silver nanoclusters by grafting thiacalix[4]arene onto polyoxovanadates

Metalloligands provide a potent strategy for manipulating the surface metal arrangements of metal nanoclusters, but their synthesis and subsequent installation onto metal nanoclusters remains a significant challenge. Herein, two atomically precise silver nanoclusters {Ag14[(TC4A)6(V9O16)](CyS)3} (Ag14) and {Ag43S[(TC4A)2(V4O9)]3(CyS)9(PhCOO)3Cl3(SO4)4(DMF)3·6DMF} (Ag43) are synthesized by controlling reaction temperature (H4TC4A = p-tert-butylthiacalix[4]arene). Interestingly, the 3D scaffold-like [(TC4A)6(V9O16)]11- metalloligand in Ag14 and 1D arcuate [(TC4A)2(V4O9)]6- metalloligand in Ag43 exhibit a dual role that is the internal polyoxovanadates as anion template and the surface TC4A4- as the passivating agent. Furthermore, the thermal-induced structure transformation between Ag14 and Ag43 is achieved based on the temperature-dependent assembly process. Ag14 shows superior photothermal conversion performance than Ag43 in solid state indicating its potential for remote laser ignition. Here, we show the potential of two thiacalix[4]arene modified polyoxovanadates metalloligands in the assembly of metal nanoclusters and provide a cornerstone for the remote laser ignition applications of silver nanoclusters.

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.

Regulating the assembly and expansion of the silver cluster from the Ag37 to Ag46 nanowheel driven by heteroanions

Precise control over the shape and size of metal nanoclusters through anion template-driven self-assembly is one of the key scientific goals in the nanocluster community, however, it is still not understood comprehensively. In this work, we report the controllable synthesis and atomically precise structures of silver nanowheels Ag37 and Ag46, using homo (Cl^- ions) and heteroanion (Cl^- and CrO₄ ^2- ions) template strategies, along with macrocyclic p-phenyl-thiacalix[4]arene and small ⁱPrS^- ligands. Structural analyses revealed that in Ag37, Cl^- ions serve as both local and global templates, whereas CrO₄ ^2- ions function as local and Cl^- ions as global templates in Ag46, resulting in a pentagonal nanowheel (Ag37) and a hexagonal (Ag46) nanowheel. The larger ionic size and more negative charges of CrO₄ ^2- ions than Cl^- ions offer more coordination sites for the silver atoms and are believed to be the key factors that drive the nanowheel core to expand significantly. Also, by taking advantage of the deep cavity of thiacalix[4]arene with an extended phenyl group, Ag46 has been used as a host material for dye adsorption depending on the charge and size of organic dyes. The successful use of heteroanions to control the expansion of well-defined silver nanowheels fills the knowledge gap in understanding the directing role of heteroanions in dictating the shape and size of nanoclusters at the atomic level.

A classical [V10O28]6- anion templated high-nuclearity silver thiolate cluster

Polyoxovanadates (POVs) as templates are still scarcely observed in silver clusters. Herein, the largest known POV-based silver cluster (Ag50) was synthesized, which is a core-shell conformation composed of the in situ generated classical [V₁₀O₂₈]^6- core and Ag₅₀ shell, constrained by the S- and O-donor ligands with a specific distribution. Such {V₁₀O₂₈@Ag₅₀} structure displays geometric inheritance from the D_2h symmetric decavanadate to the silver skeleton. The solution behavior, solid-state stability and photoelectric properties are discussed in detail. This work provides enlightenment for the further construction of POV-templated high-nuclearity silver clusters.

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.

Recent advances in polyoxometalate-based metal-alkynyl clusters

This paper focuses on the recent advances in polyoxometalate-based metal-alkynyl clusters.

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.

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 Ag+/[PW11NbO40]4- Complexes in Nonaqueous Solutions

Self-assembly between Ag⁺ and [PW₁₁NbO₄₀]^4- in N- and O-donor solvents (nitriles and amides) has been studied. In the case of dimethylformamide (DMF), formation of a yellow [Ag₄(DMF)₁₂][PW₁₁NbO₄₀] (1a) metastable phase and a colorless [Ag₄(DMF)₁₀][PW₁₁NbO₄₀] (1) stable phase was observed. In acetonitrile (CH₃CN), the product was [Ag(CH₃CN)₄]₂{[Ag(CH₃CN)₃]₂[PW₁₁NbO₄₀]} (2a). By contrast, [SiW₁₂O₄₀]^4- of the same size and charge as [PW₁₁NbO₄₀]^4- produces [Ag(CH₃CN)₃]₄[SiW₁₂O₄₀] (3a). Partial desolvation of 2a and 3a leads to Ag₄[PW₁₁NbO₄₀]·7.5CH₃CN (2) and Ag₄[SiW₁₂O₄₀]·7.5CH₃CN (3), respectively. The CH₃CN molecules in the structure of 2 are labile, and this compound was used as the starting material to study solvent-exchange processes in N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMA), diethylformamide (DEF), and benzonitrile (PhCN) solutions. These solvent reactions yield [Ag(DMA)₄][Ag₃(DMA)₆][PW₁₁NbO₄₀] (4), [Ag₂(NMP)₄(CH₃CN)]₂[PW₁₁NbO₄₀]·1.3NMP (5a), [Ag₂(NMP)₅]₂[PW₁₁NbO₄₀] (5b), Ag₄[PW₁₁NbO₄₀]·9.5DEF (6), and [Ag(PhCN)₄]₂[{Ag(PhCN)₃}₂PW₁₁NbO₄₀] (7). All products were isolated and characterized by single-crystal X-ray diffraction (except for 2 and 3), IR, elemental analysis, and thermogravimetric analysis techniques. The O-donor solvents favor polynuclear, solvent-bridged cationic aggregates. In the case of DMF, DMA, and DEF discrete, tri- and tetranuclear polycations are observed, while in the case of NMP, the formation of infinite polycationic structures takes place. By contrast, the N-donor solvents (CH₃CN and PhCN) favor mononuclear cations, which can exist either as distorted tetrahedral, isolated [Ag(Solv)₄]⁺ cations or as pseudotriangular {Ag(Solv)₃}⁺ units, additionally coordinated to a polyoxometalate. Screening of the luminescent properties for solid samples of 1-7 revealed that only 5a/5b and 7 are emissive. In particular, the sample containing 5a and 5b demonstrates long-lived phosphorescence with a 30 ms lifetime.

Investigation of the Effect of a Mixed-Ligand on the Accommodation of a Templating Molecule into the Structure of High-Nucleus Silver Clusters

Advancement of the synthesis and control of the self-assembly process of new high-nucleus silver clusters with desired structures is important for both the material sciences and the many applications. Herein, three new silver clusters, 20-, 22-, and 8-nucleus, based on alkynyl ligands were constructed and their structures were confirmed by single-crystal X-ray diffraction, powder X-ray diffraction, elemental analyses, and Fourier-transform infrared spectroscopy (FT-IR). For the first time, the trivalent tetrahedron anion of AsO₄^3-, as a template, and the surface ligand of Ph₂PO₂H, with new coordination modes, were employed in preparation of the silver clusters. The role of surface ligands and template anions in the size and structure of the clusters was investigated. The presence of the template in the structure of the clusters led to the formation of the high-nucleus clusters. Also, in this report, it was shown that the participation of the template in the assembly of a cluster can be controlled by the surface ligands. UV-vis absorption and luminescent properties of the clusters and the thermal stability of the 8-nucleus cluster were also studied.

Oxometalate and phosphine ligand co-protected silver nanoclusters: Ag28(dppb)6(MO4)4 and Ag32(dppb)12(MO4)4(NO3)4

Thiols, alkynyls and phosphines are the most widely used organic ligands to attain atomically precise metal nanoclusters, while oxometalates as inorganic ligands have almost been neglected in this field. Here, we used oxometalates (e.g., MoO42- and WO42-) as protecting ligands along with phosphines, such as 1,4-bis(diphenylphosphino)butane (dppb), to design and synthesize a new class of silver nanoclusters including Ag28(dppb)6(MoO4)4, Ag28(dppb)6(WO4)4 and Ag32(dppb)12(MoO4)4(NO3)4. Each cluster consists of a two-shell Ag4@Ag24 core protected by 4 oxometalates. These clusters exhibit similar optical absorption and photoluminescence properties that are not dependent on surface ligands. Furthermore, the electronic structure analysis shows that the clusters are 20-electron "superatoms". This work demonstrates that oxometalates can play a key role in the formation of silver nanoclusters, and the effect of oxometalates should be considered in the design and synthesis of metal nanoclusters.

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.

Silver(i) nanoclusters of carbazole-1,8-bis(acetylide): from visible to near-infrared emission

High-nuclearity silver(i) nanoclusters of carbazole-1,8-bis(acetylide) exhibit visible to near-infrared luminescence and gradual emission spectral red-shift with the stepwise increase of cluster nuclearity following Ag₈ → Ag₁₆ → Ag₂₉.

An atomically precise all-tert-butylethynide-protected Ag51 superatom nanocluster with color tunability

The tert-butylethynide ligand has been employed to construct an atomically precise all-tert-butylethynide-protected silver superatom nanocluster, Ag51(tBuC[triple bond, length as m-dash]C)32 (hereafter denoted as Ag51). The identity of Ag51 is confirmed by high resolution ESI-MS and elemental analysis. Single crystal X-ray analysis revealed that the structure of Ag51 features a three-shell arrangement, Ag@Ag8/Ag6@Ag36@C24/C8. Ag51 exhibits a strong solvatochromic effect, and the emissions are strongly dependent on the solvent polarity and are tunable from blue to red by changing the solvent from less polar dichloromethane to highly polar methanol.

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.

Sulfonate, sulfide and thiolate ligands into an ultrasmall nanocluster: [Ag40.13Cu13.87S19(tBuS)20(tBuSO3)12]

A novel Ag–Cu bimetallic nanocluster, Ag_40.13Cu_13.87S₁₉(tBuS)₂₀(tBuSO₃)₁₂, has been synthesized by precise control.

A giant 90-nucleus silver cluster templated by hetero-anions

A giant 90-nucleus silver cluster templated by hetero-anions was isolated and characterized.

High-nuclearity silver ethynide clusters containing polynucleating oxygen donor ligands

Three high-nuclearity heterometallic ethynide clusters were constructed with various polynucleating oxygen donor ligands.

Silver ethynide clusters constructed with fluorinated β-diketonate ligands

Phosphonate can act as the intermediate connector to link two silver ethynide clusters functionalized by hfac ligands together to enlarge the silver cluster.

Johnson Solids: Anion-Templated Silver Thiolate Clusters Capped by Sulfonate

Sulfonates were incorporated into six novel high-nuclearity silver(I) thiolate clusters under the guidance of anion templates varied from S^2- , SO₄^2- , α-[Mo₅ O₁₈ ]^6- , β-[Mo₅ O₁₈ ]^6- , [Mo₂ O₈ ]^4- , to [Mo₄ O₁₄ (SO₄ )]^6- . Single crystal X-ray analysis revealed that SD/Ag1, SD/Ag3, SD/Ag5, and SD/Ag6 are discrete [S@Ag₆₀ ], [α-Mo₅ O₁₈ @Ag₃₆ ], [Mo₂ O₈ @Ag₃₀ ]₂ , and [Mo₄ O₁₄ (SO₄ )@Ag₇₃ ] clusters, respectively, whereas SD/Ag2 and SD/Ag4 are one-dimensional (1D) chains based on the [SO₄ @Ag₂₀ ] and [β-Mo₅ O₁₈ @Ag₃₆ ] cluster subunits, respectively. Their silver skeletons are protected exteriorly by thiolates and sulfonates and interiorly supported by diverse anions as templates. Structurally, cluster SD/Ag1 is a typical core-shell structure comprised of an inner Ag₁₂ cuboctahedron and an outer Ag₄₈ shell. The sulfate-templated drum-like Ag₂₀ cluster subunits are bridged by PhSO₃^- to give a 1D chain of SD/Ag2. Complex SD/Ag3 and SD/Ag4 are spindle-like Ag₃₆ clusters with isomeric [Mo₅ O₁₈ ]^6- inside, and the latter is further extended to a 1D chain through PhSO₃^- bridges. A pair of [Mo₂ O₈ ]^4- templated gourd-like Ag₃₀ clusters are dimerized in a head-to-head fashion to form SD/Ag5. Complex SD/Ag6 is the largest cluster in this family and doubly templated by unprecedented [Mo₄ O₁₄ (SO₄ )]^6- anions. Geometrically, the silver shells of SD/Ag1-SD/Ag5 show the polyhedral features of Johnson solids, instead of the usual Platonic or Archimedean solids. Solution behaviors and luminescent properties were also investigated in detail.

A Water-Stable Cl@Ag14 Cluster Based Metal-Organic Open Framework for Dichromate Trapping and Bacterial Inhibition

Decoding the principles of cluster-based framework assembly at the molecular level remains a persistent challenge. Herein, we isolated and characterized a novel water-stable three-dimensional (3D) metal-organic open framework [Cl@Ag₁₄(cPrC≡C)₁₀Cl₂·(p-TOS)·1/3H₂O]_n (SD/Ag14, cPrC≡CH = cyclopropylacetylene; p-TOS = p-toluenesulfonate), which contains a chloride-templated Ag₁₄ cluster as building block. For SD/Ag14, one chloride acts as the template to shape the Ag₁₄ cluster and the other bridges the clusters to a 3D pcu-h open framework. As revealed by high resolution electrospray mass spectrometry (HRESI-MS), the Ag₁₂-Ag₁₄ species are potential cluster-based intermediates to the 3D pcu-h framework, which authenticates a preconceived idea that the 3D framework is hierarchically assembled from the silver clusters as observed in solid state. Interestingly, SD/Ag14 can be used effectively to remove the environmental pollutant Cr₂O₇^2- from wastewater through anion exchange in a single-crystal-to-single-crystal (SC-SC) transformation fashion. Furthermore, SD/Ag14 exhibits excellent antibacterial activity against Staphylococcus aureus, thus making it a potential antibacterial agent.

Anion-templated nanosized silver clusters protected by mixed thiolate and diphosphine

S^2-, MoO₄^2-, and Mo₆O₂₂^8- were successfully employed as templates in the formation of six high-symmetry polynuclear silver clusters as exemplified in the single-crystal X-ray structures of [S@Ag₁₈(^tBuC₆H₄S)₁₆(dppp)₄]·DMF·5CH₃CN·3CH₃OH (1), [MoO₄@Ag₂₄(MeC₆H₄S)₁₂(dppm)₆(MoO₄)₄]·2BF₄·C₂H₅NO (2), [MoO₄@Ag₂₄(MeC₆H₄S)₁₂(dppm)₆(MoO₄)₄]·2CF₃SO₃ (3), [MoO₄@Ag₂₄(MeC₆H₄S)₁₂(dppf)₆(MoO₄)₄]·2CF₃SO₃ (4), [MoO₄@Ag₂₄(MeC₆H₄S)₁₂(dppb)₆(MoO₄)₄]·2CF₃SO₃ (5) and [Mo₆O₂₂@Ag₄₆(^tBuC₆H₄S)₃₂(dppm)₄(CH₃CN)₈]·6CF₃SO₃ (6) (dppp = 1,3-bis(diphenylphosphino)propane, dppm = bis(diphenylphosphino)methane, dppf = 1,1'-bis(diphenylphosphino)ferrocene and dppb = 1,4-bis(diphenylphosphino)butane). Cluster 1 is a S^2--centered octadecanuclear banana-shaped molecule. Clusters 2-5 have similar structures consisting of a tetrahedron of a MoO₄^2- core and four MoO₄^2- where three silver atoms cap each face and a pair sits on each edge, giving tetraicosanuclear ball-shaped molecules. Although different diphosphine ligands and silver salts were used in the syntheses, 2-5 contain a common building cluster unit with similar geometry and nuclearity. With (Bu₄N)₂Mo₆O₁₉ as a template, a giant 46-silver-atom cluster encapsulates an in situ modified Mo₆O₂₂^8- unit. The nuclearity and geometry depend on the size and shape of the templates. High-resolution electrospray mass spectrometry (HR-ESI-MS) analyses of 4 indicate its exceptionally high stability in acetonitrile. The solid-state luminescence of 1 as a function of the temperature exhibits thermochromism from red to yellow due to the different intensities of the two bands. This work established a new strategy for the construction of polynuclear silver clusters using an anionic template and mixed S- and P-donor ligands where a promising approach for building novel dual emissive materials is unraveled.

Ethynide-stabilized high-nuclearity silver(i) sulfido molecular clusters assembled using organic sulfide precursors

Inexpensive 1,1'-thiocarbonyldiimidazole and di(2-pyridyl) thionocarbonate have been used as respective sulfide precursors to assemble unprecedented high-nuclearity ethynide-stabilized silver(i) sulfido molecular clusters [Ag9S6@Ag36(C[triple bond, length as m-dash]C(t)Bu)32(H2O)2] [Ag(imidazole)(CH3OH)(H2O)](BF4)2·8H2O·2CH3OH (1) and [Ag120S24(PhC[triple bond, length as m-dash]C)52Cl4(2-pyridone)10(H2O)8](H3O)4(SiF6)8(BF4)4·CH3OH·22H2O (2), the latter being the largest isolated silver(i) ethynide cluster reported to date.