Constructing Atomically Precise Nanoclusters Based On D¹⁰Metal Cyclical Trinuclear Complexes:Synthesis,Characterization And Exploration Of Photoluminescence Property

Recently,the atomically precise noble metal nanoclusters,as one of the attractive type of nanomaterials,have aroused increasing research interests,due to their ultrasmall size,low toxicity,strong photoluminescence and tunable chemical composition.Several methods,such as one-pot synthesis,ligand exchange,and metal exchange methods,have been applied in synthesizing atomically precise nanoclusters with various sizes and compositions.Remarkably,the luminescence properties of some obtained materials are comparable to or even superior than those of the classic fluorescent nanomaterials and organic dyes.Herein,a series of novel atomically precise nanoclusters were obtained by metal doping and reactivity modulation.Through studying the photoluminescence properties and the related mechanisms of them,the relationship between structures and properties were deeply explored in our works.In Ag₁₃3 nanocluster system,Ag₃pz₃ was synthesized firstly as a precursor and then Ag₁₃3 was obtained by diffusion synthesis.Through adding different proportion for Cu₃pz₃ in-situ synthesis,two Cu-doped isostructural clusters,Ag_11.8Cu_1.2 and Ag_11.3Cu_1.7,were obtained and exhibited quiet different luminescence properties from that of Ag₁₃.Noteworthily,the absolute quantum yield of Ag_11.8Cu_1.2 and Ag_11.3Cu_1.7.7 are even higher than 60%,while that of the Ag₁₃3 is lower than 0.01%.After analyzing the results of experiment data and theoretical calculations,it is revealed that the heavy atom effect of Cu atoms makes the main contribution to the enhancements of the absolute quantum yield.The results indicate that doping of metal ions is an effective way to obtained nanocluster materials with enhanced luminescence properties.In Ag₂₀0 nanocluster system,Ag₂₀ nanoclusters were synthesized by Ag₃Pz₃,with enough phenylacetylene,in certain reaction conditions.The calabash-shaped metallic kernel of Ag₂₀0 is surrounded by fourteen phenylacetylene and four pyrazole ligands.Ag₂₀0 is not stable in air and its luminescence was hardly detected at room temperature.However,its emission properties is extremely enhanced at cryogenic temperature.If added less phenylacetylene and no Et₃N during synthesis,only Ag₃ was obtained,which shares the same structure with Ag₃Pz₃.Ag₃ emits blue luminescence upon excitation at 365 nm.The structural transformation of high-nuclearity silver clusters from small one to another bigger one induced by cluster reactivity is of scientific significance.It is the first time to synthesis nanoclusters simplified method with two different Cyclic Trinuclear Complexes as precursor.By changing the concentration of the second ligands,two novel Ag clusters,Ag₁₃3 and Ag₂₀,were obtained and explored their photoluminescence properties.Based on the results of the high-resolution mass spectrometer and single-crystal diffractometer,the relationships between the compositions and properties of these clusters were studied in our works,which may provide some insight into the related researches of nanoclusters.