| Over the years,people have been committed to the development and research of organic fluorescent materials with excellent performance,because they have great application value in cell imaging,light-emitting diodes,photoelectric devices,sensors and so on.Most traditional fluorescent molecules have the problem of aggregation induced quenching（ACQ）.Fortunately,in 2001,an unusual phenomenon of aggregation induced luminescence（AIE）was discovered by Tang benzhong’s team.In addition,the AIE properties of organic compounds are often accompanied by mechanofluorochromic properties.Compounds with mechanofluorochromic properties can be used in anti-counterfeiting and safety inks.On the other hand,people have gradually developed the application of AIE in sensing,and ion recognition is one of the main applications.However,the recognition of ions by sensors usually depends on the pure organic solvent environment.At present,only a small number of sensors that can recognize related ions in aqueous mixed organic solvents have been reported.Most of the actual biological samples or environmental samples are aqueous systems,so the sensors with AIE properties are more suitable for practical applications.According to these background,we refer to the similar work and determine a reliable synthesis route,and successfully prepared several organic molecules with corresponding functions.First,three molecules with AIE properties were synthesized by combining tetraphenyl ethylene and fluorene,but the mechanofluorochromic properties were different.Secondly,using 9-fluorenone and anthraquinone as starting materials,two molecules with both AIE and mechanofluorochromic properties were synthesized.Finally,two fluorescent or colorimetric sensors based on triphenylamine and tetraphenyl ethylene were synthesized.The contents of this paper are as follows:In the first chapter,the corresponding background of AIE compounds is introduced,the research progress of AIE molecules and mechanofluorochromic molecules is briefly introduced,and the application of AIE molecules in sensors is also introduced.The proposal of this project is based on the study of the photophysical properties of the synthesized molecules.In the second chapter,three fluorescent molecules,TPE-2FL-0,TPE-2FL-2 and TPE-2FL-4,were synthesized by the combination of tetraphenyl ethylene and fluorene via Buchwald Hartwig aromatic amination reaction.The difference between them lies in the different alkyl chains.The results show that their mechanofluorochromic properties are related to alkyl chain,and they all have excellent AIE properties,but they have different mechanofluorochromic phenomena.TPE-2FL-0 has reversible mechanofluorochromic properties,TPE-2FL-2 has no mechanofluorochromic properties,and TPE-2FL-4 has irreversible mechanofluorochromic properties.In Chapter 3,two triphenylamine derivatives FL-2TPA and AN-4TPA based on Fluorene or anthracene were synthesized by Wittig reaction and Suzuki coupling reaction respectively.The experimental results show that both molecules have AIE properties and reversible mechanofluorochromic properties.In Chapter 4,the sensing molecules S-1 and S-2 were synthesized by multi-step Suzuki coupling reaction and the introduction of recognition groups.The experimental results show that S-1 has AIE property,while S-2 has no AIE property.In addition,S-1 can recognize Hg2+in DMSO-water(Vwater=50%)mixed solvent.The fluorescence intensity of molecule S-1 in DMSO-water(Vwater=50%)mixed solvent gradually weakened and slightly red shifted with the addition of Hg2+,and then turned to very weak yellow fluorescence when Hg2+reached saturation equivalent and fully responded.However,molecule S-2 recognizes HS-in the system of pure dimethyl sulfoxide,which has no fluorescence in pure solvent or aqueous solvent.The color of the solution changes from colorless to brown with the addition of HS-and has a low detection limit. |
