Study On Synthesis And Application Of Sulphur Dioxide Fluorescent Probe Based On Carbazole

Sulfur dioxide（SO₂）molecules play a very important role in industrial manufacturing and organisms.SO₂ has the functions of inhibiting bacterial growth,preventing enzymatic browning and resisting oxidation,and is often used as a preservative and antioxidant in the manufacturing process.In addition,endogenous SO₂ can be produced in organisms and participate in physiological and pathological activities of organisms as gas signal molecules.However,abnormal SO₂ may destroy the cell’s homeostasis,causing adverse reactions such as diarrhea,asthma,allergic reaction and hypotension,as well as respiratory and cardiovascular diseases,lung cancer and many neurological diseases.Therefore,it is of great significance to monitor the dynamic changes of SO₂ in organisms in real time.Organic small molecule fluorescent probe has the advantage of real-time in-situ biological imaging,and can recognize the change of fluorescence signal caused by response with target molecules in vivo,so as to realize the detection of target molecules,which is an indispensable research tool in chemistry and biology.In addition,the fluorescent probe has the advantages of simple operation,good repeatability and cost-effective,and also plays its role in food detection and environmental detection.Dye is the main structure for constructing fluorescent probes.Carbazole fluorophores have the advantages of high quantum yield,good photostability,bifunctional modification and electron-rich mechanism.Therefore,carbazole is widely used as a dye in fluorescent probes,and is often used as an electron donor to design various D-A or D-π-A ICT fluorescent probes.In this paper,carbazole was selected as fluorophore,and three fluorescent probes were designed and synthesized by modifying fluorophore,which were used to detect the concentration changes of biological weight sulfur dioxide and its derivatives(HSO₃^-/SO₃^2-).First,A novel multifunctional fluorescent molecule（TCMn）with AIE properties was synthesized,with carbazole as the fluorophore and the introduction of diphenylamine and malononitrile groups to form an intramolecular push-pull electron system to enhance the fluorescence of carbazole derivatives and carbon-carbon double bonds as SO₂ recognition sites.The probe TCMn can specifically identify exogenous and endogenous sulfur dioxide derivatives in living cells.Based on the excellent AIE characteristics of probe TCMn,probe TCMn has a good application prospect in the development of fluorescent ink.What’s more,since the probe TCMn is able to extract information about potential fingerprints on multiple matrices,it provides a simple and widely applicable method for the visualization of potential fingerprints.Secondly,with benzothiazole group as electron-withdrawing group,diphenylamine group as electron-donating group,and carbon-carbon double bond as recognition site of sulfur dioxide derivatives,a new type of ratio fluorescence probe TCMs was designed and synthesized to detect sulfur dioxide derivatives.The prepared fluorescent probe has large Stokes shift（150nm）,high ratio response multiple（142-fold）,a lower detection limit of SO₂ derivatives（47 n M）.Using the probe TCMs,we have successfully detected SO₂ derivatives in cells.In addition,the probe TCMs has high sensitivity to SO₂derivatives in real food samples.Moreover,the fabricated test strips could be used to assess the amount of SO₂ derivatives in aqueous solutions by natural light or fluorescence.Finally,design and synthesis of a ratiometric fluorescent probe TCMo for the detection of sulfur dioxide derivatives in organisms and cells.A new fluorescent probe（TCMo）was designed based on carbazole as fluorophore,malononitrile as electron-withdrawing group and carbon-carbon double bond as the SO₂ recognition site.The probe has the ability to detect sulfur dioxide derivatives by the ratio fluorescence intensity of 470 nm and 630 nm.It has high selectivity and sensitivity for sulfur dioxide derivatives,low detection limit（62 n M）and fast identification（within 120 s）.In biological imaging,the probe TCMo has been successfully used to detect not only exogenous and endogenous sulfur dioxide derivatives in cells,but also sulfur dioxide derivatives in mice.