Thiophenethiol Functionalized Metal-Organic Frameworks:Design,Synthesis And Optical And Electrical Properties

Metal-Organic Framework(MOF)has many advantages,such as its highly ordered structure,adjustable pore size,controllable size and morphology,predictable topology and modifiable functions,so this material has developed rapidly in various application areas.Generally speaking,there are two main strategies for synthesizing functionalized MOF.One is to first design and synthesize functionalized ligands and then assemble them with metal ions to obtain MOFs.Another is to assemble unfunctionalized ligands with metal ions to obtain MOFs,and then introduce functionalized groups or components through post-modification strategies.The methods of post-modification mainly include covalent modification,doping,exchanging ligands or metal ions,and increasing defects.Based on the previous research work,this thesis designs and synthesizes two new organic sulfur-containing ligands,prepares four new MOFs and explores their properties.The specific research contents are as follows:First,the background of this subject is summarized,and the characteristics and applications of the metal-organic framework are introduced,and the research content and topic significance of this thesis are explained.Secondly,zirconium-based metal-organic framework Zr BPD-L with thiophenethiol functionalization was designed and synthesized,and its thiophene side chain was oxidatively cross-linked through post-synthesis modification.The chemical stability and electronic conductivity of the oxidized Zr BPD-L-Ox are greatly improved,and its electronic conductivity can reach 2.2×10^-3 S·cm^-1.The proton conductivity of H₂SO₄@Zr BPD-L-Ox loaded with sulfuric acid can reach 1.62×10^-3 S cm^-1at 80°C at90%RH,which is thousands of times higher than that before loading.Third,a series of two-dimensional layered metal-organic frameworks Eu-L,Tb-L and Dy-L with dinuclear rare earth metal clusters functionalized with thiophenethiol were designed and synthesized.The fluorescence characteristics of Eu-L and Tb-L were systematically studied.The application of Eu-L in heavy metal detection was further explored,and it was found that it has a strong selective fluorescence response to silver ions.In addition,the magnetic property of Dy-L was also explored and it was found that it is an antiferromagnetic material.Finally,a three-dimensional zinc-based metal-organic framework Zn-L functionalized with thiophenethiol was designed and synthesized.It can maintain crystallinity after exposing to the air for 21 days and immersing in boiling water for 30hours,which is more stable than unfunctionalized zinc-based MOF.The fluorescence properties of Zn-L were systematically studied.In addition,the proton conductivity of NH₄Br@Zn-L loaded with ammonium bromide is four orders of magnitude higher than that before loading,which proves that loading the proton carrier in the water-stabilized MOF can effectively increase the proton conductivity.