Research On Synthesis And Ion Recognition Performance Of Self-assembled Supramolecular Fluorescence Chemical Sensor

In recent years,fluorescent chemical sensors have become indispensable tools in many fields of science and technology due to their strong specificity,high accuracy,super sensitivity,and high selectivity.Supramolecular fluorescent chemical sensors based on self-assembly generally contain intermolecular hydrogen bonds,van der Waals forces and?-?stacking and other non-covalent bonding forces,which lead to such fluorescent chemical sensors with molecular polymorphism and reversibility.Based on these excellent properties of fluorescent chemical sensors,they are widely used in ion recognition,molecular recognition,bioimaging and detection of harmful substances in food.Fluorescence chemical sensor have received a lot of research and development in the past few decades.Research progress on fluorescence chemical sensors at home and abroad in recent years was summarized in this paper,and on this basis,this thesis designs and synthesizes three chemical sensors based on fluorescent materials,and studies their applications in the detection of anions and cations.The main work carried out is as follows:1.A new type of fluorescent chemical sensor G based on acylhydrazone group was successfully synthesized by connecting gallic acid derivatives and biphenyl aldehyde by acylhydrazone bond,which can realize ultra-sensitive detection of Pd2+in aqueous solution.Sensor G self-assembles through?-?stacking,van der Waals forces and intermolecular hydrogen bonds in the organic solvent DMF to form a stable supramolecular organogel OG,and produces an aggregation-induced effect（AIE）.The aqueous solution of Pd²⁺was added in OG,the fluorescence of the system was quenched,and its lowest detection limit（LOD）was 2.03?10^-8M,the resulting metal gel Pd G can also recognize H₂OP₄^-in the anion.Finally,a new type of heterogeneous catalyst Pd@OG was prepared with xerogel OG as the carrier.More importantly,this new type of high-efficiency catalyst can be reused at least 5 times,and the catalytic activity of the C-C coupling reaction is not reduced.2.A new type of multi-channel chemical sensor TBT was synthesized by reacting gallic acid derivatives with benzoyl chloride.The sensor forms a suspension in the organic solvent i-Pr OH and self-assembles into a multidimensional network structure through?-?stacking,van der Waals forces and intermolecular hydrogen bonds.Cu²⁺,Fe³⁺,Cr³⁺and Co²⁺in water super sensitively were detected through fluorescence by chemical sensor TBT,when Cu²⁺,Fe³⁺,Cr³⁺and Co²⁺ions were added,the fluorescence of the system is quenched at 466 nm,the detection limits are 6.5×10^-8M,4.7×10^-8M,5.8×10^-8M and 4.1×10^-8M,respectively.3.This article is based on environmentally friendly,green and pollution-free palygorskite（PGS）,functionalized grafted with 3-aminopropyltriethoxysilane（APTES）,and further grafted with a biphenylaldehyde fluorescent luminescence Group（TB）,and finally form a fluorescent chemical sensor PGS-APTES-TB,the sensor produces aggregation induced fluorescence effect（AIE）in ethanol solution and emits bright blue fluorescence.And use it in the ultra-sensitive fluorescence detection of Cu²⁺,Fe³⁺and NO₂^-,because of its environmental protection and low toxicity,it can be used for the detection of nitrite in food.According to the detection experiment on bacon,ham and mustard tuber,it can be seen that the fluorescent chemical sensor PGS-APTES-TB can be successfully used in food Nitrite detection.