Triphenylamine-based Fluorescent Molecules And Conjugated Polymers For Applications In Sensors

The fluorescent probe is one of the important contents in the fluorescence analysis techniques.These probes can bind to the target substance specifically,so that their fluorescence spectra are changed significantly in emission wavelength and fluorescence intensity.Several targets can be detected by fluorescent probes including various ions,p H,free radicals,temperature,viscosity,polarity,and so on.Fluorescent probes not only achieve some simple detection methods,but also show several outstanding advantages in terms of selectivity,sensitivity,time resolution,and real-time monitoring ect.With above advantages,the fluorescent probes are widely used in environmental monitoring,clinical analysis,biological analysis,and life sciences.It has received widespread attention from scientists in different fields.Through fluorescence analysis technology,they can gain the information of the target ions concentration in complex systems and intracellular fluorescence imaging.In this dissertation,triphenylamine fluorophore was used as precursor to design and synthesize two small molecular sensors for detecting metal ions.Then,two conjugated polymers were designed and synthesized with these sensing segments.The structures of probes were characterized by ¹HNMR,¹³CNMR and HRMS.The properties of the fluorescent probes were tested and studied by UV-vis and fluorescence spectroscopy.The research work of this dissertation mainly included the following aspects:In the first chapter,I introduced the basic model and research progress of fluorescent chemical sensors briefly,and gived four basic design principles of fluorescent chemical sensors.Several metal ion fluorescent molecular probes for detecting Zn²⁺and Hg²⁺were introduced and gave the concept of conjugated polymers.Finally,according to the previous work of our research group,I gived the basic design ideas and research methods of this paper.In the second chapter,a triphenylamine-based fluorescent molecular sensor TPAI with 8-hydroxyquinoline unit was designed and synthesized.The fluorescent molecular probe could identify zinc ion in a complex system quickly.According to the fluorescence spectral titration curves,the probe TPAI showed high capability to complex zinc ion,and could realize the quantitative detection of low concentration of zinc ion.In the third chapter,a tetrasulphite-containing fluorescent chemodasimeter for mercury ion with optimized selectivity towards silver ion was designed and synthesized.Compared with the traditional probe molecule TPAII-1,the probe molecule TPAII-2could overcome the interference of silver ion,and increased the selectivity to mercury ion.According to the fluorescence spectra titration curve,the probe molecule TPAII-2 has a lower detection limit in the HEPES buffer solution than in the organic solvent and could be used for fluorescence imaging of mercury ion in living cells.In the fourth chapter,I expanded the fluorophores into the main chain of the conjugated polymer,using 2,2’-（9,9-dioctyl-9H-fluorene-2,7-diyl）bis（4,4,5,5-tetramethyl-1,3,2-dioxaborolane）as a comonomer.The target conjugated polymers TPAIII-1 and TPAIII-2 were obtained through the Suzuki coupling reaction under the action of the phosphine-palladium catalyst,and their structures were characterized.