Doping And Properties Of Silver And Copper Nanoclusters Protected By Thiol Ligands

Heterometallic doping has now become a new method to control the structure and properties of nanoclusters,and has achieved fruitful research results.With the help of the precision of the nanocluster structure,scientists have carried out a series of studies on the doping of heterometals（including copper,platinum,palladium,cadmium,mercury,nickel）on Au₂₅,Ag₂₉,Au₃₈ and other classic coinage metal nanoclusters.In addition,the structural relationship between the parent clusters and their different foreign metal-doped clusters,as well as the stability,luminescence,and catalytic properties of the dopant clusters were investigated.However,the existing work mainly focuses on the doping research of Au nanoclusters,while the doping research of Cu and Ag nanoclusters is still rare.Therefore,in order to further enrich the field of doped nanoclusters,this paper will focus on the doping of Cu,Ag nanoclusters,and explore the effect of doping on the structure and properties of the clusters.The specific research contents and results are as follows:1.9,12-dimercapto-1,2-o-carborane was used as the protective ligand to synthesize cyclic copper nanoclusters Cu₁₆(C₂B₁₀H₁₀S₂)₈(abbreviated as Cu₁₆)by one-pot co-reduction method.And Cu₁₆ exhibits strong orange-red fluorescence.After that,10%-40%（mmol）ratio of Au atoms was doped,and the composition and structure were proved by electrospray ionization mass spectrometry（ESI-MS）and X-ray single crystal diffraction（SC-XRD）analysis,respectively Cu_16-nAu_n(C₂B₁₀H₁₀S₂)₈（n=0～3）（NC1）,Cu_16-nAu_n(C₂B₁₀H₁₀S₂)₈（n=0～4）（NC2）,Cu_16-nAu_n(C₂B₁₀H₁₀S₂)₈（n=0～5）（NC3）,Cu_16-nAu_n(C₂B₁₀H₁₀S₂)₈（n=0～8）（NC4）.It is worth noting that the doping of a large number of Au atoms did not significantly change the structure of the nanoclusters.In addition,with the increase of the doping ratio of Au atoms,the photoluminescence（PL）intensity of the nanoclusters gradually weakened;and the nanoclusters showed obvious Aggregation-Induced Emission（AIE）properties.This work realizes the control of the luminescence of the clusters through the doping of the nanoclusters,and reveals that the doping strategy of the nanoclusters is expected to be a new way to control the luminescence of the nanoclusters.2.Based on the silver nanocluster Ag₃₄S₂（PhCH₂S）₁₈（CF₃COO）₉（DMF）₆(abbreviated as Ag₃₄)with a 3-electron open-shell electronic structure.With a little change in synthesis steps,that is,adding Ag（PPh₃）NO₃,and introducing a strong reducing agentNa BH₄,anewsuperatomicsilvernanocluster Ag₃₆（PhCH₂S）₁₈（CF₃COO）₁₀（DMF）₄（PPh₃）₂(abbreviated as Ag₃₆)was obtained by a one-pot co-reduction method.It has 8 free electrons and has obvious fluorescence signal in the near-infraredⅡregion.On the basis of Ag₃₆,the doping of Pd atoms was carried out,and the successful doping of Pd atoms was characterized by single crystal X-ray diffraction and EDS,XPS,EPR and other characterizations,PdAg₃₅（PhCH₂S）₁₈（CF₃COO）₁₀（DMF）₄（PPh₃）₂(abbreviated as PdAg₃₅),in which the Pd atom replaces the Ag atom in the center of the Ag₃₆ icosahedral core,and has 7 free electrons.The comparison shows that they have similar structures and exhibit similar optical properties.Preliminary cluster-catalyzed singlet oxygen experiments show that Ag36 exhibits good catalytic effect;theoretical calculation results further show that the HOMO-LUMO band gap and electronic structure of the three are changed due to the slight changes in structure and composition.This work not only enriches the types and structures of superatomic silver nanoclusters,but also demonstrates the effect of heterometallic doping on the electronic structure and the band gap of silver nanoclusters through doping strategies.There are 56 figures,11 tables and 146 references.