Study On Synthesis And Optics Properties Of Zn~?-ln~? Compounds Based On A New Amide-imine Semi-rigid Ligand

The Zn^?-Ln^?heterometallic complexes have attracted attention due to their high nuclearity,diversity,complexity and characteristics in optics,magnetism,and catalysis.In particular,their optics can not only be applied to biological imaging,medical and fluorescent probes,but also be used as potential luminescent materials.Therefore,the construction of multifunctional rare earth heterometallic complexes with different structures is one of the important contents of the development of rare earth functional materials.By introducing pyrazolone into the salicylamide-imine semi-rigid ligand,the N heterocyclic new polydentate ligand(E)-2-hydroxy-N-(3-(((5-hydroxy-3-Methyl-1-phenyl-1H-pyrazol-4-yl)(phenyl)methylene)amino)propyl)-3-methoxybenz amide(H₂L)was synthesized.And a series of novel Zn^?-Ln^?heterometallic complexes were obtained by solvent evaporation method at room temperature.The introduction of pyrazolone functional group not only enriches the structure of salicylamide-imine multidentate ligands,regulates the conformation and electronic properties of such ligands,but also enriches the study of the structure and properties of Zn^?-Ln^?heterometallic complexes.Based on the characterization of the composition and structure of the series of complexes,including infrared spectroscopy,thermogravimetric analysis,and X-ray diffraction,the optical properties and fluorescence response were studied.The research content of this paper is mainly divided into the following three chapters:Chapter 1:The research progress of 3d-4f complexes in magnetic,catalytic and optical properties in recent years is briefly introduced,especially the research results of Zn^?-Ln^?bimetallic complexes in optical sensing and dye adsorption.On this basis,the meaning and significance of the topic of the dissertation is proposed.Chapter 2:Using phenylhydrazine and methyl 3-methoxysalicylate as starting materials,theintermediateproduct4-benzoyl-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one(PMBP)and monolateral amine N-(3-aminopropyl)-2-hydroxy-3-methoxybenzamide were obtained by step reaction,and the target ligand(E)-2-Hydroxy-N-(3-(((5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)(phenyl)methylene)amino)propyl)-3-methyl Oxybenzamide(H₂L)was obtained through amine aldehyde condensation reaction.And seven isomorphic tetranuclear complexes[Zn₂Ln₂L₄(NO₃)₄]·x CH₃OH·y CH₃CN·z H₂O were obtained in a mixture solvent of acetonitrile and methanol of about 2:1 by room temperature volatilization,and referred to as Zn₂Ln₂(Ln^?=Pr^?,Nd^?,Eu^?,Tb^?,Ho^?,Er^?and Gd^?)and a single rare earth complex Er₂L₂(NO₃)₂,and the obtained polycrystalline samples of the complex were characterized by infrared,thermogravimetric and XRD.Chapter 3:Studies on the luminescence properties of the series of complexes show that the Zn^?-L chromophore can not only sensitize the luminescence of rare earth ions in the visible region,but also sensitize the luminescence in the near-infrared region,making the series of Zn^?-Ln^?bimetallic species appear the characteristic emission of rare earth ions.Studies on the fluorescence response of the complex Zn₂Tb₂ show that in the buffer solution of p H=7.2,the complex Zn₂Tb₂ can selectively recognize Cu²⁺and 3-nitrophenol(3-NP)based on the fluorescence quenching effect.In particular,it should be pointed out that,Zn₂Tb₂ can realize the recognition of Cu²⁺by naked eyes.The p H gradient experiment shows that the recognition of Cu²⁺by the complex Zn₂Tb₂ can be applied to physiological conditions.The study of the recognition mechanism shows that the selective fluorescence quenching of Zn₂Tb₂ by Cu²⁺is based on the mechanism of the excitation efficiency,while the selective fluorescence quenching of Zn₂Tb₂ by 3-NP is the result of the combined effect of the excitation efficiency and light-induced electron transfer.The research results of this thesis have important theoretical significance and potential application value for the preparation and application of optical properties of Zn^?-Ln^?bimetallic compounds with novel structure and excellent optical properties.