Dissolution-enhanced Emission Of Organic Small Molecular Sensor And The Fully Conjugated 3D COFs:The Synthesis And Fluorescence Properties

While satisfying human production and life,the chemical industry has also brought some negative impacts on humans,including metal ion pollution,organic waste pollution,and dangerous gas leakage.The fluorescence analysis method has the advantages of short analysis time,high detection sensitivity,simple operation of the instrument,and low detection cost.It not only has great potential in the field of hazardous substance detection,but also has emerged in the field of life medicine.The main research contents are as follows:1.After aggregation-induced emission mechanism has been proposed,it has been used as a general strategy for designing Turn-On probes,which has set off a wave of research in the field of fluorescence sensing.In this paper,a fluorescent probe 1,3,6,8-tetrakis(4-carboxyphenyl)pyrene(TBAPy)with a simple structure and no metal elements is proposed.The molecule can achieve high-sensitivity detection of arginine and lysine by fluorescence enhancement effect in aqueous solution.In this paper,the sensitivity,anti-interference and detection limits of TBAPy probe for detecting arginine and lysine are studied in detail.The detection limits of TBAPy probe for arginine and lysine were 2.3 × 10-6 M and 2.2 × 10-6 M,respectively.And through the response of TBAPy to different pH solutions,the suitable pH range for TBAPy probe to detect arginine and lysine was determined.According to the nuclear magnetic resonance hydrogen spectrum before and after adding arginine or lysine in the TBAPy detection system.We first proposed the mechanism of Dissolution-enhanced emission(DEE)to explain its fluorescence phenomenon.The proposed DEE mechanism further enriches the strategy of designing fluorescence-enhanced probes.2.Designed and synthesized a "saddle-shaped" three-dimensional conjugated ligand-COThP-CHO,and further successfully synthesis three-dimensional fully conjugated covalent organic frameworks BUCT-COF-1 with p-phenylenediamine by solvothermal method.The experimental results show that the specific surface area of BUCT-COF-1 can reach 976.6 m2/g and the pore size distribution is 1.17 nm.At the same time,BUCT-COF-1 not only has high thermal stability but also has excellent fluorescence sensing performance.We have studied in detail the fluorescence detection performance of BUCT-COF-1 for metal ions and nitro explosives,and found that BUCT-COF-1 can achieve high selectivity and high sensitivity detection of Fe3+ through competitive absorption mechanism and fluorescent internal filtering effect.And it can realize the selective detection of 2,6-dinitrophenol in the presence of trinitrophenol.The successful preparation of BUCT-COF-1 not only fills the gap in the field of fully conjugated 3D covalent organic frameworks materials,but also provides new ideas for the design of fully conjugated 3D covalent organic framework materials.