Synthesis And Properties Of Copper Based Nanoclusters

Atomically precise metal nanoclusters have attracted abundant attention recently,due to their unique electronic structures and unusual physical and chemical properties,which make them promising application potentials in numerous fields,such as catalysis,electronics,chemical sensing,bioimaging and biomedicine.In the past few decades,the synthesis,structure determination and properties of coinetallic nanoclusters have made rapid progress.Unlike gold and silver nanoclusters,there are still many problems in the synthesis and application of copper nanoclusters due to their poor stability,which seriously hinders the development and application of copper nanoclusters.In this work,we have successfully synthesized a Cu23 nanocluster and a novel bimetallic cluster AgCu16,by exploring different synthetic methods.The main research work of this thesis is as follows:1.Synthesis of atomically precise copper nanoclusters by gradient reduction strategy.In this work,we investigate a gradient reduction strategy(GRS)for the preparation of copper nanoclusters.By using different reducing agents,we have realized the evolution of copper atom from divalent to monovalent and eventually to zero valence.Using this strategy we have successfully synthesised a Cu23 nanocluster with a[Cu4]0 tetrahedral kernel.And the cluster can crystallise in two different solvents to form two compounds[Cu23(tBuC?C)13(CF3COO)6]and[Cu23(tBuC?C)13(CF3COO)6]·CHCl3 with different space groups.By analysing single crystal diffraction data of two compounds,we found that weak intermolecular interactions and van der Waals forces are important factors in the polymorphism of nanoclusters.2.Synthesis and assembly mechanism of Ag-Cu bimetallic cluster.We have successfully isolated two bimetallic clusters with the same main structure[Ag@Cu12S8@Cu4(dpph)6]+by using[PhC?CCu]n precursor,silver powder,1,6-bis(diphenylphosphine)hexane and Ph3CSH as reactants,which can be viewed as a cuboctahedral Ag@Cul2 nanocluster through four ?4-S2-ions anchored in a Cu4(dpph)6 tetrahedral cage.The successful synthesis of the cluster provides a geometrically matched model of cuboctahedral clusters with tetrahedral coordination cages,further advancing the development of host-guest system.Moreover,we have also carried out a series of mass spectrometry tests on the cluster by varying the collision energy to study its fragmentation process in the gas phase.Combined with its structural characteristics,we propose a possible assembly mechanism of bimetallic nanoclusters in solution,which laid the foundation for the realisation of controlled synthesis of bimetallic nanoclusters.