Synthesis And Properties Of Functional Aggregation-induced Emission Compounds

Organic molecules with Aggregation-induced Emission（AIE）properties are widely used in fluorescent chemical sensing,detection and imaging of biological,high-performance optoelectronic devices,environmental monitoring and intelligent materials.This thesis mainly focuses on the application of AIE in the detection of mercury ions and the evaluation of microbial adsorption capacity to mercury ions,as well as the application of AIE in the response to acid-base stimuli and the instant detection of aquatic product freshness.The typical AIE molecules-tetraphenyl ethylene（TPE）and 9,10-distyrylanthracene（DSA）were used as fluorescent chromophores,and different recognition sites were introduced.The fluorescence signal changes in of TPE and DSA were used to detect mercury ion and NH₃.The specific research content is as follows:1.Fluorescent probes evaluate the adsorption capacity of Gram-negative bacteria to Hg²⁺.A novel fluorescent compound Tetra（（4-bis（2-hydroxyethyl）amino）methyl phenyl）ethene（3）was synthesized and used as a fluorescent probe for detecting Hg²⁺.The probe showed a low fluorescence intensity in aqueous solution,but the fluorescence intensity was significantly increased when Hg²⁺was added to the solution.Further addition of lipopolysaccharide（LPS）to the system could further enhance the fluorescence intensity of 3,because the binding between 3-Hg²⁺and LPS activates the Aggregation-induced Emission（AIE）properties of compound 3.Therefore,this fluorescent probe 3 is used as a fluorescent marker to monitor the interaction between Hg²⁺and LPS interactions.Since LPS is the main substance forming the outer wall of gram-negative bacteria,we added compound 3 labeled Hg²⁺into different Gram-negative bacteria,and realized the real-time and rapid evaluation of the adsorption capacity of Gram-negative bacteria to Hg²⁺through the change of fluorescence intensity of compound 3.2.Synthesis and application of fluorescent compounds containing DSA structure in response to acid-base stimulation.Using anthracene as the starting material,9,10-dichloromethylanthracene is obtained through chloromethylation reaction,and then 9,10-bis（4-aldehyde styryl）anthracene is synthesized through Arbuzov reaction and Wittig-Horner reaction.The target compounds DSA-2Py and DSA-3Py were obtained by Knoevenagel condensation reaction with 2-pyridine-acetonitrile and 3-pyridine-acetonitrile,respectively.Since the target compound has excellent solid fluorescence properties,and the pyridine structure in the molecule has typical protonation and deprotonation reaction properties,the photophysical properties of the HCl/NH₃ reversible stimulation response of two DSA derivatives are mainly studied in this thesis.Furthermore,we prepared protonated DSA derivatives into smart labels,which are used to monitor the deterioration process of aquatic products-shrimps at different temperatures,and realize the functional application of DSA derivatives.The above research content combines organic AIE molecules with traditional molecular recognition（metal ions,acid and base）,and exploits the advantage of excellent photophysical properties of AIE molecules in the aggregation state to expand the functionality of organic AIE small molecules,which has certain practical value and potential application prospects.