Synthesis Of Luminescent Metal-organic Frameworks And Its Application In Fluorescent Detection

Metal-Organic Frameworks(MOFs)is a category of crystalline porous materials which consist of metal or metal cluster and organic linker through coordination interaction.Taking the advantage of a wide range of selectable metals and well-designed ligands,it is suitable for designing MOFs containing fluorescence function and responding to the external stimulation.This thesis is focusing on design and synthesis of novel fluorescent MOFs based on fluorescent metal or ligand,and its fluorescent property which was explored in terms of different interaction with external molecules that was further applied in analytical chemistry fields.The specific contents are concluded as fellow:1.Three kinds of MOFs were synthesized using zinc(Zn),cadmium(Cd)or Zn and Cd as metal center linked with fluorescent ligand,respectively.Herein,the stability of these MOFs was studied.The results show that Zn and Cd bimetallic MOFs(Zn-Cd-MOF)has the best stability in aqueous system.Simultaneously,it found that the fluorescent emission wavelength and intensity of the proposed Zn-Cd-MOF had a change with the content of water in organic solvent.The possible reason is that intramolucular hydrogen-bond was existed in the ligand.However,intermolecular hydrogen bond between water molecular and ligand may be formed when Zn-Cd-MOF was dispersed in the organic solvent containing water,which changed conformation of ligand.Furthermore,fluorescence signal of Zn-Cd-MOF was changed.The method of detecting water in organic solvents was established based on above-mentioned principle.2.Lanthanide MOFs was formed through the coordination interaction between hexanuclear europium(Eu)cluster and 2,2'-bipyridine-5,5'-dicarboxylic acid.Then terbium(Tb)was modified by means of coordinating with bipyridine.Then the dual emission fluorescence property of MOFs was endowed.However,unsaturated coordination site of Tb could further interact with anthrax spores biomarker,2,6-pyridine-dicarboxylic acid.By means of this interaction,fluorescence intensity of Tb was enhanced based on “antenna effect”.In contrast,fluorescence intensity of Eu has no changed.In this way,spores biomarker was analyzing in ratiometric fluorescent method through differential sensitization toward lanthanide.3.Three different metals were employed to construct MOFs with triphenylamine-based ligand containing molecule rotor.The fluorescence change was explored according to different viscosity,temperature or host-guest interaction of size of molecule owing to the restricted rotor of benzene ring in ligand.As a result,fluorescent signal changed variously due to different pore size from different MOFs.Organic amine could change MOFs' fluorescence distinctly.Finally,matrix-mixed membrane was prepared doping fluorescent materials in large scale.