Reactive Fluorescent Probes' Design And Synthesis And Application

With the development of science and technology,people's awareness of environmental protection has gradually increased,and at the same time,the understanding of life sciences has gradually become deeper.Therefore,there is an urgent need to develop new methods for real-time environmental pollutants and ions,living biological small molecules,enzymes,etc.that participate in life activities,monitor.Although traditional methods,such as electrochemical method,mass spectrometry,etc.,have been widely used for the detection of pollutants and physiological activity-related species,most of these methods have certain drawbacks and factors that limit their application,such as expensive equipment,inconvenient operation,and procedures.Complex,long detection time,and so on.Therefore,the development of new detection methods is an urgent problem to be solved.Fluorescence analysis is a good solution to the many shortcomings and limitations of the traditional detection methods,and therefore has been widely used in recent years in the detection of pollutants,food testing,medical treatment and other fields.Meanwhile,developing a sensor system that can detect and analyze analytes effectively has drawn extensive attention in the fields of Supramolecular and biochemical fields.As a branch of the sensor system,the fluorescence sensor is even more eye-catching.Fluorescent probes refer to a generic class of organic compounds that can detect one or more specific analytes and show the result of detection through the change of fluorescence signal.Compared with other technologies,fluorescent probes have the advantages of high sensitivity,high selectivity,low cost,easy operation and real-time monitoring of targets,so they have been widely used in living cells,tissues and animals.In this paper,we use benzopyran,benzothiazole and carbazole as fluorescence signal groups respectively.Fluorescent probes for the detection of sulfite/bisulfate,hydrazine hydrate were constructed.The main work is as follows:(1)as for the limitations of fluorescence-enhanced and fluorescence-attenuating probes for single fluorophore synthesis,such as probe concentration,environmental influence,and excitation energy,we designed a benzopyran-based ratiometric fluorescent probe based on the Michael addition mechanism to overcome these problems,with the detection line reaching 6.1×10-7M.The probe can effectively solve the external disturbance caused by self-calibration of two emission bands.External interference problems with self-calibration.At the same time,we successfully applied the probe to the fluorescence imaging of HeLa cells,which also proved that the probe can actually detect the concentration of sulfite ions in the cells.(2)Hydrated hydrazine,a typical reducing agent and foaming agent,is widely used in pharmacy,agricultural production and preparation of polymer foams,and hydrazine hydrate is highly toxic to human and animals.Toxicity experiments have also shown that irreversible damage to the liver,lungs,kidneys,and central nervous system occurs after prolonged exposure to high levels of hydrazine hydrate.Meanwhile,hydrazine hydrate also has potential carcinogenicity and mutagenic effects.In view of the above situation,we chose a hydroxybenzothiazole with excited proton transfer fluorescence emission as the parent fluorescent molecule and malononitrile as the recognition group to develop a fluorescence enhanced N2H4 fluorescent probe HBTM.The fluorescent probe is used to detect hydrazine hydrate.The probe is very selective,and the detection line is 2.9×10-7M,which is lower than the standards of the American Environmental Protection Association.In view of the excellent detection performance of HBTM on N2H4,we successfully performed colorimetric detection of N2H4 at different concentrations on the filter paper and detection of intracellular exogenous N2H4,which provided strong support for the potential application of HBTM in actual samples and cells.(3)Based on the work of the second chapter,we further designed fluorescein probes based on intramolecular charge transfer(ICT)mechanisms using carbazole as a fluorescent group,malononitrile and phthalimide as double recognition sites.DCMM is a typical fluorescence quenching probe,and its fluorescence emission intensity at 538 nm shows a clear linear relationship with N2H4 concentration(0-6?M).By calculation,the detection limit of DCMM for N2H4 is 4.7×10-8 M,which is far below the US Environmental Protection Agency standard.At the same time,we successfully achieved fluorescent colorimetric detection of different concentrations of N2H4 on filter paper.