Synthesis And Luminescent Properties Of Tetraphenylethylene Derivatives Based Ionic Compounds

Tetraphenylethylene(TPE),as a typical molecule with Aggregation-Induced Emission(AIE),has a unique propeller-like structure.Because of its simple synthesis,convenient modification and excellent optical properties,it has attracted much attention in the field of organic fluorescent materials and is a rising star.How to modify TPE reasonably and turn on or off AIE when needed is the key to the application of TPE derivatives.In this paper,we synthesized three kinds of TPE derivatives,which can be completely dissolved in water and can quickly turn on the AIE phenomenon in the presence of heparin.In addition,rare earth elements have excellent optical,electrical and magnetic properties,so they have always been the key research objects in the field of scientific research,and they are also indispensable strategic resources for the country.In particular,in the field of optics,because rare earth elements have many electronic excitation energy levels,their fluorescence emission can cover the whole range of visible and near infrared wavelengths.However,due to the barrier of 4f-4f transition,rare earth elements usually need to be sensitized by sensitizers.Through the proper method of combining TPE derivatives with rare earth elements,introducing the AIE mechanism into the field of rare earths,and discussing the interaction between fluorescent groups,it is of great significance for fluorescence regulation.In the second chapter,we introduce pyridine ring into TPE group by Suzuki coupling reaction,and then introduce amino and ionic bonds through the nucleophilic substitution reaction of pyridine and halogenated hydrocarbons,and synthesize three kinds of TPE derivatives.These three TPE derivatives are composed of TPE-based cations and simple bromine ions and have certain water solubility.Moreover,different amounts of charge and amino groups have a certain effect on the water solubility of TPE derivatives,which is further confirmed by Tyndall effect and Lamberbier’s law,and the appropriate solution concentrations of the three compounds in water are found.By measuring the fluorescence spectra of ethanol/ethyl acetate mixed system,it is found that in the high ethyl acetate phase,the fluorescence of the three compounds is enhanced,which has a typical AIE effect.In addition,we synthesized three water-soluble TPE derivatives with AIE effect,which can be used as fluorescence probes for heparin detection,and each probe has its own advantages and can be applied to various scenarios.It is believed that these three kinds of fluorescence probes have a wide application prospect in the field of fluorescence detection.In the third chapter,inspired by the binding of TPE sequence cations and heparin anions in Chapter 2,we found that counterions have a very significant effect on the molecular accumulation and fluorescence of TPE motif cations,but most researchers do not consider the luminescence of anions themselves.Therefore,we synthesized an ionic rare earth complex and combined the rare earth complex anions with TPE motif cations.A new type of organic rare earth complex was constructed,which can be due to both the excellent optical properties of rare earth and the AIE effect of TPE motif.By studying the changes of its fluorescence properties in different proportions of DMF/water,we established that it has unique AIE/ACQ dual properties,and discussed the intramolecular energy transfer pathway through the data of fluorescence lifetime,UV and phosphorescence spectra,and made a preliminary explanation for the unique dual fluorescence properties of AIE/ACQ.In addition,we also found that the system has the property of coordinated fluorescence,and the fluorescence emission of the system can be regulated by adding ATP and polyacrylic acid,which provides a new idea and method for the design of tunable fluorescent molecules.