Synthesis Of Organic And Mesoporous Materials-based Fluorescence Sensor And Their Detection Of Water Content

Water is the most important component of organisms and the important resource for all living things.However,as a pollutant and harmful impurity in organic solvents,the presence of trace amounts of water can cause serious hazards to chemical reactions and industrial production,such as fires and explosions.Therefore,convenient,rapid and accurate detection of low content water in organic solvents is very important.Among the many detection methods,fluorescence analysis is widely used in the analysis and detection field due to its advantages of simple operation,high sensitivity,portability and real-time.Based on this,a series of organic and mesoporous materials-based fluorescence sensors were designed and synthesized to detect the water content in the organic solvents.The main research contents of this paper are:1.Naphthalimide was selected as the fluorescence signal group to synthesize N-propyl,N-hydroxypropyl,4-hydroxyl,and N-hydroxypropyl and 4-hydroxyl substituted naphthalimide derivatives,namely PNI,HONI,PNIOH and HONIOH,respectively.In this paper,the effects of the substituent groups on the photophysical properties of the compounds were investigated under different p H values and in different solvents.p H does not affect the optical physical properties of PNI and HONI.The response ranges of PNIOH and HONIOH to p H were 5.5 < p H < 7 and 1.5 < p H < 10,respectively.Solvent does not affect the color of PNI and HONI under sunlight lamp and 365 nm UV irradiation.PNIOH can divide the solvent into two types with blue fluorescence and yellow fluorescence.HONIOH not only can qualitatively identify DMF,but also has the ability to distinguish Me OH from Et OH.As described in the review,the synergistic effect of N-hydroxypropyl and 4-hydroxyl enhances the sensitivity of HONIOH to p H and solvent changes.2.Based on the second chapter,HONIOH was used as a fluorescence sensor to detect water content in organic solvents.The photopysical property of HONIOH in water were significantly different from those of HONIOH in organic solvents,such as DMF,THF,AN and Acetone.Based on this,the effects of water content in organic solvents on the photophysical properties of HONIOH were further investigated.The results showed that,HONIOH had good performance in the determination of low-content wate in DMF,THF,AN and Acetone,with the minimum detection limits of 0.017%,0.066%,0.089% and 0.048%,respectively.3.Dansyl and pyrene were selected as fluorescent groups to synthesize compound PDH with double fluorophore.The fluorescence properties of PDH and single fluorophore compounds Dns–Hz and Py H were investigated in different solvents to explore the ability of solvent discrimination by the synergistic mechanisms of intra–molecular charge transfer(ICT),monomer–exicimer formation and fluorescence resonance energy transfer(FRET),and to study the ability of water content identification in PDH organic solvents.4.The mesoporous material Py H–SBA–15,PHC–SBA–15 and Py U–SBA–15 were prepared by grafting pyrene into the pore of SBA-15 with different ligands.The spectroscopic properties of organic molecules grafted into SBA-15 and the effect of ligands on the spectroscopic properties of mesoporous materials were investigated.Py U–SBA–15 can be applied to the detection of water content in methanol and ethanol,with detection limits of 0.02% and 0.2%,respectively.