Synthesis,Structures And Fluorescent Property Of High-Nuclearity Silver-Ethynide Clusters

The high-nuclearity silver cluster is constructed with a plurality of silver atoms by argentophilic interactions.The structure of the silver clusters is different depending on the template anions and the peripheral ligands introduced during the self-assembly.High-nuclear silver clusters with various structures through self-assembly process obtained by researchers,and the properties of silver clusters in fluorescence,magnetic and biological aspects,which is of great significance for the application and development of silver clusters also studied.At present,the research on high-nuclearity silver clusters is mainly divided into two categories.The first type is to construct high-nuclearity silver clusters by using halogen anions or polyoxometalate anions as template;the second type is to construct an atomiclly precise silver nanoclusters by reduction reactions with reductant such as sodium borohydride.In this dissertation,we have done a lot of research on the synthesis of these two types of silver clusters and obtained a series of high-nuclear silver clusters.The crystal structures were characterized by single crystal X-ray diffraction,and the fluorescence properties of some clusters also studied.The main research contents and results of this paper are as follows:?1?A series of Ag-Ln bimetallic clusters were obtained by silver salt precursor ^tBuC?CAg reacting with ^tBuPO₃H₂ ligand and rare earth salts Ln?hfac?₃?2H₂O?Ln=Eu,Sm,Pr,Nd,Dy,Gd,Yb?.The single crystal structure of these bimetallic silver clusters has been characterized,and the fluorescence properties of several silver clusters with good reproducibility?2a,2b,2e,2i,2l and 2m?have also been studied.As researches showed that these Ag-Ln clusters exhibited the fluorescence emission of trivalent rare earth ions.[Cl@Ag₁₄?^tBuC?C?₁₂]?[Ln₃?^tBuPO₃?₂?hfac?₆?CH₃OH?₆]?Ln=Eu 2a,Sm 2b,Pr 2c,Nd2d,Dy 2e,Gd 2f,Yb 2g?[WO₄@Ag₂₄?^tBuC?C?₂₀]?[Ln₃?^tBuPO₃?₂?hfac?₆?CH₃OH?₆]₂?Ln=Gd 2h,Eu 2i?[SO₄@Ag₂₂?^tBuC?C?₁₈]?[Sm₃?^tBuPO₃?₂?hfac?₆?CH₃OH?₆]₂?2j?[Ag?bipy?₂][Yb₃?^tBuPO₃?₂?hfac?₆?CH₃OH?₆]?2k?[Cl@Ag₁₆?^tBuC?C?₉?hfac??CH₃CO₂?][Yb₃??₃-OH???₂-OH?₃?^tBuPO₃?₃?hfac?₃?CH₃OH?₃]·4CH₃OH·H₂O?2l?[Cl@Ag₁₆?^tBuC?C?₇?hfac?₂?^tBuPO₃??CH₃OH?]₂[Yb₆??₃-OH?₂??₃-O?₆?^tBuPO₃?₆?H₂O?₆?CH₃OH?₆]?2m??2?Two kinds of Ag-Cu high-nuclearity clusters 3a and 3b were obtained by silver salt precursor ^tBuC?CAg reacting with ^tBuPO₃H₂ ligand and transition metal copper-substituted polyoxometalate under solvothermal conditions.Based on the synthesis method of 3a and 3c,a 51-nuclear silver-ethynide cluster 3c was obtained by changing the ^tBuPO₃H₂ligand to ⁿBuPO₃H₂ ligand.And after adding CS₂ as a reactant,we obtained a 70-nuclear silver-ethynide cluster 3d.{[(SiW₉O₃₄)@Ag₃₄Cu₆?^tBuC?C?₁₈?^tBuPO₃?₉?CH₃CN?₂?H₂O?]·2CH₃CN}?3a?{[(SiW₉O₃₄)@Ag₃₇Cu₆?^tBuC?C?₁₈?^tBuPO₃?₉?CH₃CN?₆]·0.5[SiW₁₂O₄₀]·[OH]}?3b?{[?WO₆?(SiW₉O₃₄)@Ag₅₁?^tBuC?C?₂₇?ⁿBuPO₃?₃?CH₃CO₂?₃?CH₃CN?₃]·0.5[H₈SiW₁₂O₄₀]·B F₄}?3c?{[?WO₄?₂(Ag₁₆S₆)@Ag₅₆?^tBuC?C?₂₇?^tBuPO₃?₁₂?CH₃CO₂??CH₃CN?₂?H₂O?]·[H₂P₂W₁₈O₆₂]}?3d??3?An all alkynyl-protected 51-nuclear atomically precise nanocluster 4d was obtained by reduction reaction of silver salt precursor ^tBuC?CAg with 1,3-bis?diphenylphosphino?propane?dppp?ligand.The structure of 4d features a Ag@Ag₁₄@Ag₃₆ three-shell arrangement,which is protected by 32 tBuC?C^-ligands in a special geometric configuration.The fluorescence properties of 4d dissolved in different polar solvents have been characterized,the results showed that the nanocluster exhibited solvatochromism properties.Cl@Ag₁₈?^tBuC?C?₁₂?^tBuPO₃?₂BF₄?4a?SiF₆@Ag₂₂?^tBuC?C?₂₀?4b?Ag₆?dppm?₄?PhC?C?₄?BF₄?₂?CH₂Cl₂?4c?Ag₅₁?^tBuC?C?₃₂Cl?4d??4?Two atomically precise nanoclusters 5a and 5b which protected by inorganic oxygen-containing ligands were obtained by reduction reaction of silver salt precursor ^tBuC?CAg with 1,4-bis?diphenylphosphino?butane?dppb?ligand and polyoxometalate templates.The two silver nanoclusters feature an Ag₄@Ag₂₄ metal core structure.Based on the synthesis method of these two silver clusters,an atomically precise nanocluster 5c with larger framework was obtained after changed the silver salt to AgNO₃.This silver nanocluster also have an Ag₄@Ag₂₄ metal core structure,but there are more dppb ligands existing as prepheral protective ligands.Ag₂₈?dppb?₆?MoO₄?₄?5CH₃OH?5a?Ag₂₈?dppb?₆?WO₄?₄??H₂O??5b?Ag₃₂?dppb?₁₂?MoO₄?₄?NO₃?₄?5c?S@Ag₁₁[CS₂N?CH₂CH₃?₂]₉?5d?Ag₆?ⁱPrS?₆?dpph?₂?5e??MoS₄?@Ag₅₈S₂₄O₄?dppb?₁₂?5f?.