Synthesis,Structures And Properties Of Silver Chalcogenolate Cluster-Based Assembled Materials

Silver nanoclusters are new categories of compounds with atomically precise formed by the argentophilic interactions of several or even hundreds of silver atoms.They exhibit potential application values in the fields of catalysis,chirality,chemical sensing,etc.,and are favored by scholars from all walks of life,due to their fascinating structures and excellently photophysical properties.However,the shortcomings of silver nanoclusters,such as the difficulties of directional synthesis and low stability,limit their potential applications in various fields.Therefore,it is of great research significance to develop controllable synthesis methods and improve stability of silver nanoclusters.Silver（I）chalcogenide cluster-based assembly materials are highly ordered MOFs-like assembled materials formed by the coordination of organic or inorganic ligands and atomically precise silver（I）chalcogenide clusters nodes.The fixation of silver（I）chalcogenide clusters with rigid ligands can effectively improve their stability,while the introduction of functional ligands can endow the assembly materials novel properties.Therefore,a series of silver（I）chalcogenide cluster-based assembly materials with stable structure and excellent performance are prepared by using functional organic or inorganic bridging ligands linked silver（I）chalcogenide clusters as secondary building units.This paper mainly includes the following three parts:（1）We designed and synthesized two chain-like silver（I）chalcogenide cluster-based assembled materials with the ten-core silver（I）chalcogenide clusters nodes and the bidentate nitrogen-containing bridging ligands（bpy=4,4’-bipyridine）:[Ag₁₀（S^tBu）₆（CF₃CF₂CO₂）₄（bpy）₂]_n（2）.Upon loss of the coordinated acetonitrile molecules,compound 1 with green photoluminescent adopts a single-crystal to single-crystal transformation to form compound 2 with the cores slightly distorted evidenced by single-crystal X-ray diffraction（SCXRD）analyses,being accompanied with photoluminescence quenching,the process is cyclically reversible.Compound 2 bears distinctive solvent-dependent sensitivities to acetonitrile,exhibiting photoluminescent“on-off”switch（<1s）triggered by acetonitrile solvent or gas.Density functional theory（DFT）calculations further proved the role of acetonitrile molecules in the structural transformation process and the relationship between structure and photoluminescence.This study provides strategies for preparing stimulus-responsive silver（I）chalcogenide cluster-based assembly materials.（2）By introducing oxygen-rich polyanions polyoxometalates（POMs）with multiple coordination sites to the silver（I）chalcogenide clusters assembly system via one-pot strategy,two novel silver（I）chalcogenide clusters-based assembled materials were synthesized:chain-like structure[Ag₁₀（S^tBu）₆（CH₃CN）₈(Mo₆O₁₉)₂·2CH₃CN]_n（3）and layered structure[Ag₁₈（S^tBu）₁₂（CH₃CN）₅(Mo₆O₁₉)₂·Mo₆O₁₉·2CH₃CN]_n（4）.It is worth noting that compound 3 exhibits excellent green photoluminescence properties due to the charge transfer from ligand to metal center.Compound 4 is an elegant Ag-S sheets structure formed by cycle-Ag₁₀S₁₀ bridged Ag₃S^tBu and Ag CH₃CN.Among them,[Mo₆O₁₉]^2?not only acts as inorganic ligands to support the Ag-S layers to enhance the stability of the structure,but also acts as counterions filling the gaps of cycle-Ag₁₀S₁₀ to balance the charge of the whole molecules.Compounds 3 and 4 have similar electrochemical redox activity to[Mo₆O₁₉]^2?,indicating that the introduction of functional ligands into the assembly materials can endow silver（I）chalcogenide clusters with specific properties.（3）Using Keggin-type POMs[PMo₁₂O₄₀]^3?with acidic and redox as functional inorganic ligands,we designed and synthesized the silver（I）chalcogenide cluster-based assembly materials based on POMs[Ag₁₂（S^tBu）₆（CH₃CN）₁₂(PMo₁₂O₄₀)₂]_n（5）.Compound 5 not only retains the inherent optical property of silver（I）chalcogenide cluster,but also introduces the ability of storing and transferring electrons to assembly materials through introduced POMs.Compound 5 exhibits excellent photocatalytic hydrogen evolution performance through the synergistic effect of silver（I）chalcogenide clusters and POMs.This research provides new ideas for the development of catalytic applications of silver（I）chalcogenide clusters.The above studies show that introduced functional ligands to the assembly materials not only improve the stability of silver（I）chalcogenide clusters,but also endow the assembly materials with novel properties,such as photoluminescence,electrochemical properties,and photocatalytic hydrogen production performance,so on.