Preparation Of Microporous MOFs Based On Tricarboxylic Acid Ligands For Fluorescence Sensing And Adsorption Properties

Metal-organic frameworks（MOFs）are a type of coordination polymer that self-assembles from metal ions（clusters）and organic ligands under certain conditions.MOFs have been widely used in gas storage and separation,drug delivery and bioimaging,catalysis,fluorescence sensing,and adsorption due to their structural and functional diversity,porosity,designability,and tunability.However,most of the current MOFs-based fluorescence sensing platforms can only carry out single-target detection and single-peak detection,and detection limits need to be further improved.In addition,most MOF materials used as adsorbents have poor stability and cannot simultaneously adsorb multiple dyes.Therefore,in view of the existing issues in the fields of fluorescence sensing and adsorption of MOFs,combined with the porosity,designability,and modifiability of MOFs,MOFs materials were successfully prepared for the fluorescence sensing of drugs and metal ions,as well as for the adsorption of organic dyes.The specific work contents are as follows:1.A microporous Tb-MOF（Tb-TATB）with a three-dimensional structure was synthesized by a solvothermal reaction using the tricarboxylic acid ligand 2,4,6-tris（4-carboxyphenyl）-1,3,5-triazine（H₃TATB）as an organic ligand.Tb-TATB has water stability,excellent thermal stability,and superior luminescent properties,which lay the foundation for fluorescence detection.Due to competitive absorption of excitation energy,Tb-TATB can achieve fluorescence quenching detection of Fe³⁺,Cu²⁺,andα-cyano-4-hydroxycinnamic acid（α-CHC）with low detection limits of 4.84μM,2.92μM,and 1.96μM,respectively,enabling multi-functional sensing of Fe³⁺,Cu²⁺,andα-CHC.2.A microporous anionic MOFs material（TATAB-In）was synthesized by the solvothermal method with the tricarboxylic acid ligand 4,4’,4’’-s-Triazine-1,3,5-triyltri-p-aminobenzoic acid（H₃TATAB）as the organic ligand and In³⁺as the metal center.TATAB-In exhibits good thermal and excellent water stability,laying the foundation for the adsorption of organic dyes in aqueous solutions.Due to the pore structure,anionic framework,and multifunctional sites of TATAB-In,it achieves good adsorption performance for organic dyes,with adsorption performances in the order of VB>BG>MB>R6G>RB>MO>CR,and can almost completely adsorb VB,BG,and MB within 24 hours.In addition,TATAB-In can also achieve good separation of two mixed dyes.This work demonstrates the effective adsorption of multiple single dyes and the adsorption separation of two mixed dyes.3.The anionic microporous MOF material TATAB-In was used as a precursor,and Tb³⁺was introduced into its framework to create Tb@TATAB-In,a Tb³⁺-characteristic luminescent material.Based on the characteristic luminescence of the rare earth element Tb³⁺and the fluorescence of the ligand,Tb@TATAB-In can realize sensitive detection of Fe³⁺and proportional detection of Cu²⁺.The detection limit of Tb@TATAB-In for Fe³⁺is 1.52μM,and the proportional detection limit for Cu²⁺is8.91μM.Based on the different fluorescence responses of Tb@TATAB-In to Cu²⁺and Fe³⁺,a decoder logic gate was designed to distinguish between Cu²⁺and Fe³⁺.Compared with Tb-TATB,Tb@TATAB-In has significantly improved sensitivity for the detection of Cu²⁺and Fe³⁺.