Silver Sulfide Clusters Research Articles

Silver(I) Sulfide Clusters Protected by Rhodium(III) Metalloligands with 3-Aminopropanethiolate.

The two homochiral AgIRhIII nanoclusters, Δ6/Λ6-[Ag11S{Rh(apt)3}6]9+ ([1]9+) and Δ6/Λ6-[Ag13S{Rh(apt)3}6]11+ ([2]11+), in which Ag11S and Ag13S cluster cores, respectively, are protected by fac-[Rh(apt)3] metalloligands, were newly synthesized from fac-[Rh(apt)3] (Hapt = 3-aminopropanethiol) and Ag+ in water in combination with sulfide sources. While [1]9+ was produced by using d-penicillamine as a sulfide source, the use of HS- as a sulfide source afforded [2]11+ without causing any precipitation of Ag2S. Cluster [1]9+ was convertible to [2]11+ via the reaction with Ag+, which led to a turn-on-type switch in photoluminescence from nonemissive [1]9+ to emissive [2]11+.

N-Heterocyclic Thione-Protected Ag4 Tetrahedra and Ag8 Cubes Cocrystallized in a Single Crystal.

Polynuclear silver clusters have attracted intensive attention in the academic community owing to their rich physicochemical properties. The development of thione-protected silver clusters has been lagging behind the well-explored thiolate-protected silver-sulfide clusters. Herein, we report two N-heterocyclic thione-protected silver clusters: [Ag4(2-TBI)6(SO4)3]2- (Ag4) and [Br@Ag8(2-TBI)12(SO4)2]3+ (Ag8) (2-TBI = 2-thiobenzimidazol), which cocrystallize to form cluster-based molecular crystals with a CaF2-type structure. The cocrystal shows high thermal stability in air. Notably, the two cluster-based layers are alternately assembled to exhibit a unique k-vector-differential crystallographic arrangement. This work may lay a foundation for synthesis of atomically precise and stable silver clusters using readily available N-heterocyclic thione ligands.

Structures and properties of [Ag(Ag2S)n]+ clusters with n = 1–9: a density functional theory study

Silver sulfide clusters with size less than 2 nm are of much interest in photoelectric devices, such as photoconductive devices, infrared detectors and superconductors. The electronic structures of [Ag(Ag2S)n]+ (n = 1–9) clusters are investigated using the combined method of genetic algorithm (GA) and density functional theory (DFT). Results reveal that S atoms prefer to be at the tip of the structure, and Ag atoms tend to form S-Ag-S unit between two S atoms. With the increase of cluster size, the open structure evolves into closed centre-hollow structure. According to the stability analysis, [Ag(Ag2S)6]+ is a magic number cluster due to its high HOMO-LUMO gap, big average energy and high second-order energy difference. Ag-S bonds, S-Ag-S and triangular Ag3S3 units play key roles in stabilizing [Ag(Ag2S)n]+ clusters. According to the electron affinity energy analysis, the clusters are easier to get electrons when n = 1, 3, 5 and 9. Based on the charge analysis of the studied clusters, the charges on Ag and S atoms are positive and negative, respectively, which indicates that the charge transfer from Ag to S occurs in cluster. Infrared and Raman spectra are dependent on the symmetries of the clusters. The molecular orbitals of [Ag(Ag2S)6]+ and [Ag(Ag2S)8]+ present superatomic properties. We hope that the clusters studied here could provide valuable data for future experimental and theoretical study of cationic silver sulfide clusters.

Systematic study on the structures and properties of (Ag2S)n (n = 1-8) clusters.

Silver sulfide is a famous semiconductor, which can be used in many areas. Understanding the size evolution of silver sulfide clusters is useful in controlling their size to improve their properties in applications. The structures of (Ag2S)n (n = 1-8) clusters are explored using a combined method of genetic algorithm (GA) and density functional theory (DFT). The TPSSh/def2-tzvp(Ag)/6-311G(d)(S) method has been used to optimize the structures. The re-optimized structures and refined energies are computed at PBE0/Lanl2tz(Ag)/6-311G(d,p)(S) level according to the benchmark calculations. The global minimum (GM) structures, HOMO and LUMO frontier orbitals, density of states, ionization potentials, electron affinity energies, noncovalent interactions, and natural populations of the clusters have been studied. The clusters evolve from open to cage structures when n varies from 1 to 8. A triangular Ag3S3 unit is found to be an important building block, which can construct the global minimum structures of (Ag2S)n (n = 3-8) clusters. When n > 6, quadrangular Ag4S4 rings present in (Ag2S)n clusters. (Ag2S)6 and (Ag2S)8 clusters are in hollow conformation, and both of which have special stability because of their high HOMO-LUMO gaps, high ionization potentials, and Ag⋯Ag attractive interactions in them. Graphical abstract.

Catalyzed assembly of hollow silver-sulfide cluster through self-releasable anion template

Hollow nanoclusters are intriguing for bridging the gap between small metal-organic cages and hollow nanoparticles and provide enormous opportunities for functional materials. Rational construction of hollow nanoclusters remains a challenge owing to the poor understanding of their formation pathways and difficulties in obtaining the intermediate structures. Here we report a catalyzed assembly strategy to construct hollow silver–sulfide clusters using a self-releasable carbonate template. The hollow Ag56 cluster and the carbonate-templated Ag33 intermediate are characterized by single-crystal X-ray analysis. Combining this data with a time-dependent UV-Vis spectroscopic investigation, we reveal the catalyst-like behavior of the self-releasable carbonate template and propose the corresponding mechanism. The assembly of hollow clusters using a self-releasable template may provide insight into understanding the formation mechanisms of other hollow nanoclusters and facilitate the design and construction of new hollow nanoclusters.

Towards atomically precise luminescent Ag2S clusters separable by thin layer chromatography

Synthesis of BBSH protected silver sulfide clusters.

Structure-Directing Role of Phosphonate in the Synthesis of High-Nuclearity Silver(I) Sulfide-Ethynide-Thiolate Clusters.

Phosphonate ligands as structure-directing components have been employed to construct four new high-nuclearity silver(I) sulfide-ethynide-thiolate clusters, in which silver(I) aggregates tBuC≡C⊃Ag3, tBuC≡C⊃Ag4, and 2tBuC≡C⊃Ag7 are bridged by tBuS- ligands to engender respective silver(I) ethynide-thiolate clusters functioning as integral shell components, which are supported by phosphonate ligands. In each silver(I) sulfide-ethynide-thiolate cluster, a different encapsulated silver sulfide cluster serves as a core template.

A Theoretical Investigation of the Structure and Optical Properties of a Silver Cluster in Solid Form and in Solution.

Using density functional theory (DFT) and linear and quadratic response time-dependent DFT, we investigated the structure and optical properties of a silver sulfide cluster with the interesting property of dual emission that was observed when in crystal form but not in solution. Since the dual fluorescence is observed only in the crystal, a supposition of stabilization of a higher-energy excited state by an excimer-like complex was analyzed by calculations for a cluster dimer, formed through π-stacking of aromatic groups bonded to the sulfur atoms. However, because of the complexity of the system, a simple one-dimensional method for dimer optimization, which works moderately well in predicting the red-shifted fluorescence compared to its absorption in a naphthalene dimer, predicts only partially the red shift for the emission energy. Interestingly, calculations of the two-photon absorption (TPA) cross-section on the optimized isolated cluster as well as the crystal structure geometry indicate significant off-resonance TPA. While some materials have significantly larger TPA cross-sections, such a TPA cross-section off-resonance could be useful. The high density of states in the dimer system results in a higher probability for significant resonance enhancement and thus much larger TPA cross-sections.

Adamantyl- and Furanyl-Protected Nanoscale Silver Sulfide Clusters.

The silver salts of 1-adamantanethiol (AdSH) and furan-2-ylmethanethiol (FurCH2 SH) were successfully applied as building blocks for ligand-protected Ag2 S nanoclusters. The reaction of the silver thiolates [AgSAd]x and [AgSCH2 Fur]x with S(SiMe3 )2 and 1,5-bis(diphenylphosphino)pentane (dpppt) afforded three different clusters with 58, 94 and, 190 silver atoms. The intensely colored compounds [Ag58 S13 (SAd)32 ] (1), [Ag94 S34 (SAd)26 (dpppt)6 ] (2), and [Ag190 S58 (SCH2 Fur)74 (dpppt)8 ] (3) were structurally characterized by single-crystal X-ray diffraction and exhibit different cluster core geometries and ligand shells. The diameters of the well-defined sphere-shaped nanoclusters range from 2.2 nm to 3.5 nm.

Stabilization of 2D assemblies of silver nanoparticles by spin-coating polymers

Silver nanoparticles self-assembled on poly(4-vinylpyridine) modified surfaces were spin-coated with poly(methyl methacrylate), poly(butyl methacrylate) and polystyrene from anisole and toluene solutions. The polymers filled the space between the particles thereby providing stabilization of the assemblies against particle aggregation when dried or chemically modified. The polymers did not coat the top surface of the nanoparticles offering the chemical accessibility to the metal surface. This was confirmed by converting the stabilized nanoparticles into silver sulfide and gold clusters. Etching the nanoparticles resulted in crater-like polymeric structures with the cavities extending down to the underlying substrate. Electrochemical reduction of silver inside the craters was performed. The approach can be extended to other nanoparticle assemblies and polymers.

ChemInform Abstract: Chalcogenide Clusters of Copper and Silver from Silylated Chalcogenide Sources

AbstractReview: about 150 refs.

Chalcogenide clusters of copper and silver from silylated chalcogenide sources

This review summarizes the rich structural variety of copper and silver chalcogenide clusters with protecting ligand shells of phosphane and/or organic ligands that were generated starting out from silylated chalcogenide sources. This route turned out to be fairly selective and thus allows for the isolation of uniform, polynuclear to nanosized cluster molecules that can consist of only a few or up to hundreds of metal atoms, being bridged by the chalcogen atoms. However, all of these clusters are only kinetically stable with respect to the formation of the binary coinage metal chalcogen phases, but do not collapse into the solid M(2)E materials owing to the protection by bulky ligands on the surface. Upon a more detailed analysis of the development of the structural properties with the cluster size, one recognizes differences for the particular M/E combinations: whereas copper chalcogenide and silver selenide clusters show a clear tendency to approach structural patterns of the Cu(2)E bulk, most obvious for the Cu/Se combination, this is not visible for silver sulfide clusters, even not at the largest species with 490 silver and 302 sulfur atoms. Besides the discussion on the structures of title compounds, the review presents insight into the bonding properties, reactivity, thermal and photophysical properties. The latter can be interpreted in terms of the quantum confinement effect, thus demonstrating the clusters to be understood as intermediates between mononuclear complexes and binary bulk phases.

Sequential Observation of AgnS4− (1 ≤ n ≤ 7) Gas Phase Clusters in MS/MS and Prediction of Their Structures

Recently we reported synthesis and characterization of a monodisperse thiolate-protected Ag7 cluster. Here we show in detail that a unique series of silver sulfide cluster anions (AgnS4−) were observed sequentially from n = 7 to 1 when subjecting the thiolate-protected Ag7 cluster to an MS/MS experiment. Random silver cluster anion distributions were not observed in a wide range of collision energies. This indicates the special structure and stability of these gas phase AgnS4− clusters. Global minimum search based on density functional theory-enabled basin hopping has yielded the most stable structures for AgnS4− (1 ≤ n ≤ 7). The global minima show a transition from three-dimensional to two-dimensional and then to one-dimensional geometry with decreasing n for AgnS4− clusters. This joint experimental and computational effort provides a pathway to discover and elucidate metal-sulfide clusters of unique stoichiometry, which are not accessible through conventional methods such as laser ablation of mixed meta...

Adsorptive Removal of <i>t</i>-Butanethiol Using Metal Ion-exchange Y Type Zeolite under Ambient Conditions

Adsorptive removal of t-butanethiol (TBT), an odorant additive, from city gas was carried out using metal ion-exchange Y type zeolites at ambient temperature and pressure. The adsorption capacity of TBT on Na-Y under the wet gas condition was extremely low, although that under the dry gas condition was certainly higher. The adsorption capacity of TBT on silver ion-exchange Y type zeolites (Ag(Na)–Y) increased with higher silver ion-exchange ratio in Ag(Na)–Y under wet gas condition. In contrast, the adsorption capacity of TBT on Ag(Na)–Y under the dry gas condition decreased with higher silver ion-exchange ratio in Ag(Na)–Y. Formation of silver sulfide clusters in Ag(Na)–Y causes the decrease in sulfur adsorption capacity of it under the dry gas condition. The adsorption capacity of TBT on copper ion-exchange Y type zeolites (Cu(Na)–Y) increased with higher copper ion-exchange ratio in Cu(Na)–Y under the wet gas condition. In the case of Cu(Na)–Y, the decrease of TBT adsorption capacity under the dry gas condition did not occur with higher copper ion-exchange ratio in Cu(Na)–Y. The both spent samples of Ag(Na)–Y and Cu(Na)–Y were regenerated by heat treatment in air. The decrease in adsorption capacity of TBT on Cu(Na)–Y was slightly lower than that on Ag(Na)–Y.

Photoluminescence properties of Ag2S semiconductor clusters synthesized in micropores and mesopores

Silver sulfide (Ag2S) clusters were synthesized in microporous zeolites and mesoporous AlMCM-41 by the sulfurization of Ag+ ions exchanged within the pores of the host. Characterization was performed by means of XRD, UV-Vis Ag K-edge XAFS and photoluminescence. The pore size of the host has great effects on the photoluminescence properties. Ag2S/AlMCM-41 showed photoluminescence at the longer wavelengths than Ag2S/zeolites. The photoluminescence band of Ag2S in the zeolite with 1-dimensional channels was narrow in comparison to the Ag2S in zeolites with 2- or 3-dimensional channels.

Specific Photographic and Luminescent Properties of Sulfur + Gold–Sensitized Silver Halide Emulsions

It was found that the introduction of univalent gold ions at the initial step of sulfur sensitization could lead to a dramatic fall in the light sensitivity (S) and a considerable increase in the intensity of low-temperature (Т = 77 K) luminescence (I) of silver sulfide clusters produced by sensitization. An increase in the hold time was accompanied by an increase in S and a decrease in I. The fall in S is associated with the oxidation of the silver moiety in (Ag2S)pAg+k or (Ag2S)qAg0n (q > p) clusters, which are light sensitivity centers. AgBr(I) emulsions subjected to sulfur + gold-sensitization exhibited a flash of IR-excited green luminescence from paired iodine centers. The appearance of this flash is due to the generation of deep electron traps by sulfur–gold sensitization.

Monolayers of Zeolite A Containing Luminescent Silver Sulfide Clusters

Clustered crystals: The authors demonstrate formation of stable zeolite A monolayers on quartz and subsequent “ship-in-a-bottle” synthesis of luminescent silver sulfide clusters. The pictures show the zeolite crystals at various stages of this process.

Luminescent Silver Sulfide Clusters

Silver sulfide clusters are synthesized in the cavities of sodium and calcium zeolite A microcrystals by exposing the activated Ag+-loaded zeolite to H2S. The growth of the silver sulfide clusters during rehydration of the samples is investigated by means of diffuse reflectance spectroscopy. Monomers of Ag2S are formed at low Ag+-loading through reaction of AgSH molecules, yielding colorless composites, which exhibit a characteristic blue-green photoluminescence. Yellow colored samples showing an orange-red luminescence with an average decay time of 81 μs (−160 °C) are obtained at medium silver sulfide content. Further increasing the silver sulfide loading and therefore the cluster size causes a bathochromic shift of this emission which is accompanied by a shortening of the luminescence lifetime. The samples generally exhibit large Stokes-shifts, which can be attributed to HOMO−LUMO transitions with small oscillator strengths. The Ag2S−zeolite host−guest system constitutes a three-dimensional array of sil...

Quantum-Sized Silver, Silver Chloride and Silver Sulfide Clusters

Quantum-Sized Silver, Silver Chloride and Silver Sulfide Clusters

Unveiling the Composition of Sulfur Sensitization Specks by their Interaction with TAI

A two-step process for the formation of sensitivity centers different from earlier described two-step processes was found for sulfur sensitized emulsions. After deposition of sulfur in the first step, it was found that the second step does not consist of rearrangement of sulfur over the surface, but of the supply of silver interstitial ions towards the deposited sulfur clusters. The two processes could be separated by adsorbing and desorbing TAI (4-hydroxy-1, 3,3a, 7-tetraazaindene) at/from the silver halide surface. When 1.5 mmol TAI/mol Ag is added before the sulfur reaction, the silver interstitials are immobilized but sulfur still can be deposited at the same level. By lowering the pH to 2.50 after this sulfur reaction, TAI is desorbed from the surface and the released interstitials then cause a restoration of the properties of a sulfur system without TAI. These effects could be demonstrated via diffuse reflectance spectroscopy (DRS), sensitometry and dielectric loss measurements. We could also confirm the isolation of silver sulfide clusters by TAI from other chemicals in the solution, by adsorption of TAI on the clusters.