Study On Synthesis And Properties Of Tetraphenylethylene Fe³⁺ And ROS Fluorescent Probes Based On Aggregation-induced Emission

Traditional fluorescent probes are often prone to Aggregation-caused Quenching（ACQ）phenomenon,which easily leads to problems such as low sensitivity of luminescent materials and reduced luminescence performance.However,fluorescent molecules with aggregation-induced fluorescence（AIE）phenomenon are an effective way to solve the above problems.As a typical representative of AIE molecules,tetraphenylethylene compounds have attracted wide attention in the field of fluorescent probes because of their simple synthesis,easy modification and good fluorescent properties.Fe³⁺is the activator of various enzymatic reactions,deficiency and overdose can lead to a variety of diseases,such as cancers,Alzheimer’s disease,Parkinson’s disease and so on.On the other hand,ROS plays a role in signal transduction,inflammation and carcinogenesis in biological processes,and excessive production of ROS will induce cell apoptosis.In view of the important role of Fe³⁺and ROS in environmental and physiological processes,as well as the advantages of tetraphenylethylene fluorescent probe,it is still of great significance to develop tetraphenylethylene fluorescent probe for the detection of Fe³⁺and ROS.This paper mainly introduces the following contents:（1）the compound L1 based on tetrastyrene-rhodamine bisamide was synthesized by connecting 4-（1-phenyl-2,2-di-p-tolylvinyl）aniline（TPE-NH₂）and rhodamine B acylhydrazide（Rh B-NH₂）with pyridine-2,6-dicarbonyl dichloride,and its structure was determined.Secondly,the optical properties of L1 were studied by spectroscopy.The experimental results showed that L₁ showed high selectivity and sensitivity to Fe³⁺in Et OH/H₂O（50μmol/L,v/v,11/9,Tris-HCl p H 7.0）solution.In the presence of Fe³⁺,the probe solution showed obvious color change and fluorescence change from colorless to orange.The ESI-MS study shows that the complexation ratio of L₁ and Fe³⁺is 1:1 and the detection limit is as low as 5.03×10^-6 M.Finally,the mechanism of Fe³⁺recognition by fluorescent probe L1 was discussed by NMR titration and ESI-MS,and it was applied to the detection of Fe³⁺in water.（2）L1 is also used in the detection of ROS,and its properties are studied by UV-vis and fluorescence spectra.The experimental results show that L1 can selectively recognize Cl O^-and ONOO^-in Et OH/H₂O（50μmol/L,v/v,1/1,PBS p H 7.4）solution at the same time.In the presence of Cl O^-,the probe solution showed obvious color change and fluorescence change from colorless to bright pink,and the detection limit was as low as 6.1x10^-6M.In the presence of ONOO^-,the probe solution showed obvious fluorescence quenching in 5S at 490nm,the quenching ratio was as high as 97.5%,and the detection limit was 1.43×10^-5M,and preliminary research on its recognition mechanism was studied by ESI-MS.（3）Glyoxal is used to connect TPE-NH₂ and Rhodamine B hydrazide（Rh B-NH₂）through a condensation reaction to obtain a tetrastyrene-rhodamine-based bisimine compound L₂,which is further reduced by sodium borohydride to obtain compound L3,This probe can achieve Cl O^-specific identification in Et OH/H₂O（8μmol/L,v/v,1/9,PBS p H 7.4）.In the presence of Cl O^-,the probe solution showed a color change from colorless to light pink and a significant fluorescence change at 490nm,and the detection limit was 5.31×10^-7M.Finally,the mechanism of Cl O^-recognition was studied by ESI-MS.