Synthesis,Characterization And Property Of Silver And Gold Doped Silver Nanoclusters

Due to the special nanoscale size,nanoclusters exhibit distinctive characteristics in geometric structure,electronic structure and physicochemical properties,which have great applications in many fields,such as catalysis,luminescence,biology,sensing and so on.The determination of structural ordering at the atomic level of metal nanocluster is of extreme significance for fundamental studies of nanomaterials.In this essay,low-nuclearity gold-silver clusters were systematically studied,then high-nuclearity silver nanoclusters and gold-doped silver nanoclusters protected by different ligands were synthesized and charaterized.The research work focused on core and surface structures,electronic structures and optical properties.The details are as follows:(1)A serial of silver clusters Ag8R2(dppf)4Cl4(R =-C=CPh-p-But,-SPri or-SC6H11)were synthesized.In these stuctures,the bisphosphine dppf ligand coordinates with the silver atoms in bridged form,which is helpful for stabilizing the structure.In addition,the AuxAg15-xRi2(R =-C?CFc or-C?CBut,X = 0 or 7)clusters with different alkynyl ligands or the doping Au atoms were synthesized.The resulsts indicates that the doping atoms Au and the alkynyl do not have effect on the core structures.(2)The alloy nanoclusters Au4Ag23(C?CBut)10Cl7(dppf)4X2 and Au5Ag24(C=CPh-p-But)16Cl4(dppf)4X3(X = PF6-or SO3CF3-)were successfully synthesized.The results demonstrate that the anion deriving from silver salt do not affect the metal core structure.The formations of the nanoclusters are induced by the subtle change of group on alkynyl ligand.The steric hindrance and rigidity of ligands can significantly influence the structure of nanoclusters.The two nanoclusters show distinctly different geometric structures and thus exhibit different properties.For exmpale,cluster Au4Ag23 is emissive in the NIR region both in solution and solid state whereas Au5Ag24 is only emissive in solid state.(3)Two silver clusters Ag49(C=CBut)32 and Ag43(C=CBut)24(SO3CF3)8 were successfully synthesized.Both metal cores can be regarded as the combination of two layers.Besides,the stuctures also reveal that alkynyl ligands of silver nanoclusters coordinate with silver atoms via simple modes rather than staple modes on the suface of gold nanoclusters.