Syntheses And Characterization Of Cu Clusters Protected By Alkynyl-phosphine/Sulfur-phosphine

Metal nanocluster is a kind of transition state between atoms,molecules,nanoparticles and macroscopic materials.It is usually composed of several,dozens or even hundreds of metal atoms through covalent bonding to form relatively stable cluster structure.These regular and orderly clusters can accurately determine the structure of metal nanoclusters by X-ray single crystal diffraction,which plays a positive role in promoting the study of nanoclusters.Due to the unique size effect of clusters,their physical and chemical properties are different from those of atoms,molecules and nanoparticles,and they have good potential application value in many fields such as catalysis,energy,luminescence,cell labeling,ion detection,drug transportation and photoelectric technology.The study on the structure and properties of monetary-metal nanoclusters has always been a frontier subject of researchers' concern.In particular,the research on the protection of Au,Ag,Au-Ag bimetallic clusters by alkyne ligands,phosphine ligands,sulfur ligands and selenium ligands has been widely explored,and the research on copper clusters has also been on the rise in recent years.In this paper,copper metal salts(such as:Cu(OAC)2,Cu(NO3)2,Cu(CF3COO)2,Cu(CF3SO3)2,etc.)were selected as precursors to synthesize a series of copper nanoclusters protected by alkyne phosphine ligands or thiophosphate ligands.The effects of different phosphine ligands,progenitors and ligands on the structure,growth and properties of copper nanoclusters were investigated.The main research contents and results of this paper are as follows:(1)Copper nanoclusters co-protected by alkyne-phosphinea:The influence of the methyl group on the structure of Cu nanoclusters and the bonding pattern between methyl acetylene ligands and metal atoms was investigated.Through four basic acetylene and 1,4-methyl-double diphenyl phosphine were protected to a grain of FCC structure Cu53 clusters,so by changing the position of the methyl acetylene ligand explore whether methyl position influence on the structure and properties,we through the use of 2-methyl phenyl acetylene and 3-methyl phenyl acetylene got Cu44 of two different structure and Cu20 nano clusters,and 2-methyl phenyl acetylene synthesis of copper clusters in only one bidentate phosphine ligands on a phosphine ligand,with another by oxidation combines with oxygen,and 3-methyl phenyl acetylene copper clusters structure phosphine ligand did not participate in the coordination,it is a copper nanocluster protected by all-acetylene.The different positions of methyl groups on the acetylene not only lead to changes in the structure of the copper metal cluster,but also lead to changes in the coordination of phosphine ligands.Moreover,the coordination mode of alkyne also changes from a single coordination of ?4 to?4,?3,?2.So different methyl groups can change the stacking pattern and coordination pattern of the structure.b:The effects of phosphine ligands of different lengths on the structure of copper nanoparticles protected by 2-CH3PHC=CH and the ligand pattern of phosphine ligands were investigated.Cu36(2-CH3PhC?C)23(dppe)2,Cu44(2-CH3PhC?C)28(dppp)O,Cu42(2-CH3PhC ? C)18(dppb)2(CH3COO)6 copper nanoclusters of different structures were obtained by using 1,2-diphenylphosphine ethane(dppe),1,3-diphenylphosphine propane(dppp),1,4-diphenylphosphine butane(dppb)and 2-methylphenylacetylene.Different phosphine ligands lead to different coordination modes of alkynes,and an unusual coordination mode of ?5,and the coordination of phosphine ligands is also changed.(2)Copper nanoclusters co-protected by sulfur-phosphinea:The effects of copper nanoclusters protected by phosphine ligands and different precursors on cluster structure were investigated.Cu(OAC)2,Cu(NO3)2,Cu(CF3COO)2,Cu(CF3SO3)2 and Cu(CF3SO3)2 were prepared by the ligands of triphenylphosphine(PPh3)and 4-fluorophenothiol(4-FPhSH).Cuso was obtained from copper acetate and copper trifluoroacetic acid as precursors,while Cu38 was obtained from copper nitrate and copper trifluoromesylate as precursors.Therefore,different oxygen-containing acid roots in the precursors resulted in different cluster kernel structures.b:The effect of copper nanoclusters protected by phosphine ligands on cluster structure was investigated.Use copper acetate as metal salt with 4-fluorothiophenol and 1,2-bisdiphenylphosphine ethane(dppe),1,3-bisdiphenylphosphine propane(dppp),1,4-bisdiphenyl Phosphonium butane(dppb)reacts to obtain Cu28(4-FPhS)16(dppe)4(CH3COO)4,Cu39(4-FPhS)19(dppp)3(CH3COO)6,Cu30(4-FPhS)19(dppb)3(CH3COO)2 copper nanoclusters with different structures.Clusters with different core structures were obtained due to the effects of steric hindrance.