Preparation Of Probe With Carbazole As Fluorescent Precursor And Its Application In Detection Of Small Molecular Amine And Sulfite

In recent 20 years,fluorescent probes have attracted much attention due to their high selectivity,high sensitivity,fast response speed,simple equipment,convenient operation,visual detection,strong practicability,easy popularization,and the ability to provide real-time images.This probe has been widely used to detect related small molecules such as anions,cations,metals and biology.According to the binding mode of the probe molecule and the target,it can be divided into two types:reactive fluorescent probes and complex fluorescent probes.Among them,the reactive fluorescent probe is designed according to the unique structure of the substance to be detected,and it can recognize the target with a specific,irreversible reaction,and has more excellent sensitivity and selective recognition ability.Therefore,in this thesis,three series of reactive probes were designed and synthesized by using alkenyl malononitrile,benzothiazole and benzoindole derivatives as the recognition groups,for short-chain fatty amines and bisulfites.Details as follows:1.Using alkenyl malononitrile as the recognition site and carbazole as the fluorescent group,through substitution reaction,Suzuki coupling reaction and condensation reaction,the same series of two fluorescent probes TCM and TDM were synthesized and responded to amines.Experiments have found that these two probes have exceptional sensitivity to primary aliphatic amines,with detection limits as low as nanomolar,but only micromoles can be detected for secondary amines,without reacting with tertiary amines.According to its reaction characteristics,the purpose of selectively identifying aliphatic primary amines,secondary amines,and tertiary amines can be achieved through ultraviolet spectrum and fluorescence spectrum.2.Two new fluorescent probes CTB and TCT based on carbazole and benzothiazole derivatives were designed and synthesized.The detection of sulfur dioxide derivatives can be achieved by colorimetric and ratio methods.After adding bisulfite ion,the intramolecular charge transfer process is blocked due to the nucleophilic addition reaction between the molecules,and the ultraviolet absorption and fluorescence intensity of the probe solution change significantly.At the same time,the color of the solution changes with the naked eye under natural light or 365nm fluorescence.In addition,the detection limits of the two probes for sulfite ions were calculated to be 2.21×10^-5M and 3.23×10^-6M,respectively.3.For the detection of HSO3^-,we combined a carbazole derivative with a benzoindole derivative and synthesized a novel fluorescent probe ICI based on the characteristics of Michael reaction.Due to the specific nucleophilic addition reaction between the HSO₃^-ion and the probe molecule,the probe solution undergoes significant fluorescence enhancement and visible color change.The reaction between the probe and the target in DMSO can release more than 80%of the saturated fluorescence within 50s,and has more specific selectivity and sensitivity to HSO₃^-ions than other anions and cations.