Detection Strategy Designing And Application For Reaction-based Fluorescent Probe Of Aryl Boronic Acid

Fluorescent probe has been widely used in molecular recognition,environmental detection,cell tracing and so on,because of its excellent sensitivity,simple operation and rapid response time.Reaction-based fluorescent probe is designed according to the specific chemical reaction between probe molecule and detection object,hence owning selectivity and sensitivity.In recent years,boric acid/boronate-based fluorescent probes have attracted much attention for in-situ detection of reactive oxygen species（ROS）and metal ions due to their biological compatibility and high interference resistance.However,in most cases,the boric acid/borate ester groups are introduced through modification of the complex fluorophore in order to ensure good fluorescent property of this kind of probe,which leads to sophisticated synthetic procedure,high cost and limited species.Additionally,the detection mechanism is mainly focused on REDOX reaction,while other reactions are used relatively limited.Therefore,the design strategies and types of boric acid based fluorescent probes need to be further developed.Based on this,several aryl boric acid compounds with simple structure were ultilized to be fluorescence probes for the detection of hydrogen peroxide,palladium ion and copper ion respectively by optimizing the detection strategy.The mainly contents of this thesis are as follows:（1）Based on the quinolin-8-ylboronic acid/Al（Ⅲ）fluorescent probe,a synergistic detection strategy of"REDOX-coordination"was designed for the detection of hydrogen peroxide.By adding hydrogen peroxide,quinolin-8-ylboronic acid can be easily hydrolyzed to 8-hydroxyquinoline,which then coordinated with Al（Ⅲ）to generating corresponding complex and resulted in an obvious fluorescence enhancement of 515 nm.The probe can selectively detected H₂O₂ among various oxidants,with the limit of detection（LOD）down to 1.03μM.A linear relationship between fluorescent intensity at 515 nm and the concerntrations of H₂O₂ is obtained in the range from 5 to 115μM.The probe has been not only successfully applied to the detection of hydrogen peroxide in real water samples and simulated environment,but also prepared a paper-based test strip,which exhibited a certain application prospect.（2）The application scope of similar strategies is further expanded on the basis of above mentioned work.The"oxidative coupling-coordination"synergistic detection strategy was designed for the detection of Pd（II）by using quinolin-8-ylboronic acid/Al（Ⅲ）fluorescent probe.The palladium-catalyzed oxidative coupling reaction of quinolin-8-ylboronic acid leads to the generation of 8,8’-biquinoline,which then coordinated with Al（Ⅲ）to form a strong fluorescence complex and resulting in fluorescence enhancement phenomenon.The concentrations of Pd（II）are linear related with the fluorescent intensity in the range of 8-55μM,with the LOD down to 0.53μM.It’s worth noting that the assay method can not only selectively detect Pd（II）among various metal ions,but also not interfered by the ligand in the palladium catalyst,showing high specificity.（3）A detection strategy for Cu（II）was designed based on ESIPT mechanism by using 2-aminocarbonylphenylboronic acid as probe.The boric acid group in the probe,not only serves as the recognition group of Cu（II）,but also inhibits ESIPT effect.Copper catalyzed the hydrolysis of boric acid group to hydroxyl group,leading to the ESIPT effect recovery and fluorescence enhancement.In the present of Cu（II）,fluorescent intensity increases up to 25 times.When the concentration of Cu（II）ranges from 0-22μM,the fluorescent intensity at 410 nm shows excellent linear relationship with the concentration of Cu（II）,and this sensor obtains detection limit down to 0.68μM.Fluorescent tests on other metal ions show that the probe has excellent selectivity for the detection of Cu（II）.