Synthesis And Properties Of 8-hydroxyquinoline-based Probes For Copper Ion And Benzophenone Type Luminescent Materials

Owing to their various advantages including the simplicity of synthesis,ease of modification,low toxicity and so on,organic luminescent materials have gained great attention in the field of chemical sensors,luminescent probes for biological imaging,counterfeit labeling and optoelectronic devices.In this thesis,8-hydroxyquinoline and benzophenone were used as the basic structural units to design new organic luminescent materials.We had successfully synthesized 8-hydroxyquinoline-based fluorescent probes for copper ion and benzophenone type pure organic room temperature phosphorescence（RTP）materials and thermally activated delayed fluorescence（TADF）materials.The photophysical properties or response mechanisms of these three types of organic luminescent materials were studied and analyzed.The main research contents of this paper are as follows:（1）Two new quinolone-based fluorescent probes 1 and 2 with AIE feature had been synthesized to detect Cu²⁺.Probes 1 and 2 were highly efficient,specific and regenerable for the detection of Cu²⁺,and both of them could complete the response to Cu²⁺within a few minutes.In addition,we found that probes 1 and 2 could not only detect Cu²⁺sensitively in the presence of a variety of competitive metal ions or anions,but also in a wide p H range.And the detection limits for probes 1 and 2 to detect Cu²⁺were as low as 10^-8 M level,which were much lower than the allowable standard of Cu²⁺in drinking water.More importantly,both of these probes had realized the detection of Cu²⁺in real water sample and the preparation of strip paper for the rapid and field detection of Cu²⁺.（2）Based on benzophenone and dibenzothiophene units,three pure organic RTP materials DTPM,DTPMF and DTPMCl were synthesized.All of them showed RTP in the crystalline state with millisecond-scaled lifetimes.We also studied the crystal packing and intermolecular interactions of DTPM and DTPMCl.Compared with DTPMCl,a denser packing mode and the rigid environment of DTPM could suppress nonradiative deactivation of triplet excitons,leading to more efficient phosphorescence.In addition,DTPMCl powder experienced a photochromic transition from white to yellow upon UV irradiation,which provides more possibilities for the application of RTP materials such as the preparation of counterfeit labeling.（3）The benzophenone-based target product BPDBT was synthesized via Suzuki coupling reaction.It was found that BPDBT not only showed TADF emission,but also exhibited weak phosphorescence emission at room temperature.In addition,the triplet signal can be captured by the laser flash photolysis spectrometer so that we can study the luminescence mechanism of BPDBT in detail.We also found that the lifetime of triplet state of BPDBT in deaerated methanol which was helpful for us to further study the luminescence mechanism of BPDBT.On this basis,it is expected that through further structural modification,the purpose of regulating its triplet state can be achieved,and finally some highly efficient TADF materials can be developed.