Conjugated Materials With Aggregation-induced Emission Properties For Recognitions And Detections Of Nitroaromatic Compounds

Nitroaromatic compounds such as 2,4,6-trinitrotoluene(TNT),2,4,6-trinitrophenol(PA),2,4-dinitrotoluene(DNT)are recognized explosives,which are widely used in the military field and cause serious harm to national life and property safety.Furthermore,nitroaromatic hydrocarbons are widely used in fireworks manufacturing,chemical industry,leather industry,medicine,and dyestuff industry.Leakages may occur during production,transportation,and use,which pose a threat to groundwater and soil environment.Therefore,rapid identification and detection of these compounds have always been an important subject for researchers.Among all kinds of explosive detection methods,the greatest advantage of fluorescence detection method is high sensitivity,fast response,flexibility,and unique selectivity.At the same time,the discovery of Aggregation Induced Luminescence(AIE)effect solves the problem of weak or non-luminescence of traditional fluorescent molecules in solid or aggregated states and has been widely used in chemical sensors,biomedicine,physical optoelectronics,and other fields.In view of the above considerations,this study is devoted to the design of different series of high-performance AIE active materials and the identification of nitroaromatic compounds in the environment.Firstly,a series of compounds DBT1,DBT2 and DBT3 were synthesized from dibenzothiophene and thiophene ring by introducing different numbers of cyano and ester groups.The compounds were characterized by UV-Vis spectra and fluorescence spectra.The series of compounds have excellent AIE properties.The theoretical calculation of density function shows that the confinement of intramolecular rotation and the confinement of intramolecular vibration are the main causes of their AIE phenomena.Three different compounds were used as fluorescent sensors for explosive identification.Fluorescence titration experiments showed that these compounds had a unique selective recognition effect on PA.Finally,a low-cost fiber recognition test paper was prepared by self-assembly method combined with nanocomposites,which can be used for rapid identification of explosives.Secondly,Bim1 and Bim2 were designed with 2,2'-imidazole as the parent and triphenylethylene used as the fluorescent group.Then,the ligands were coordinated with transition metal rhenium to synthesize the complexes Re1 and Re2.The molecular structure was determined by NMR,IR,and MS,respectively.The crystal structure shows that the coordination structure of these compounds changes from(M)-trans-(P)structure to(M)-cis-(M)structure.Bim1 and Bim2 can be used for the identification of nitroaromatichydrocarbon explosives in the aqueous phase and the rapid identification test paper can be used for qualitative and quantitative analysis of explosives.