Fluorescent Probe Based On Uranyl Ion Of Triphenylamine In Acid And High Water System

Uranium mining,refining and spent fuel reprocessing are mostly carried out in an acidic and high water ratio environment.This usually causes the surrounding environment to be acidic and flows into the natural environment and organisms with water,leading to the deterioration of environmental pollution and biological diseases.Compared with other methods of detecting uranyl,fluorescent probes are a convenient,low-cost and efficient detection method.Therefore,synthesizing a fluorescent probe that can specifically detect UO₂²⁺in an acidic environment and a high-water ratio system,and finally realize the detection of UO₂²⁺in actual water samples and biological samples is an important direction.In order to synthesize a probe meeting the above requirements,use triphenylamine as the parent and2-（4,5-dihydrothiazole）phenol as the recognition group to synthesize the target compound 2-（4,5-dihydrothiazole）-4-（4-Diphenylamino）phenol（hereinafter referred to as USC-001）,and has done the investigation of the fluorescence properties,the recognition performance of UO₂²⁺and the practical application ability.The first chapter made relevant research on fluorescence detection methods,introduced the recognition mechanism of fluorescent probes and the main fluorescent groups,and focused on the research of the triphenylamine group with AIE effect in fluorescence detection.And the research status of fluorescent probes for UO₂²⁺detection was summarized,and the experimental plan of this article was finally proposed.The second chapter mainly discussed the fluorescence luminescence properties of the probe USC-001.Under different water ratio conditions,it exhibited a complex luminescence mechanism.Replace the phenolic hydroxyl group of USC-001 that have the possibility to occur ESIPT mechanism with the impossible ethoxy group（USC-002）,and compared the fluorescence properties of them under the same conditions.At fw from 0%to 70%,it affected by ESIPT and ICT mechanisms,USC-001emitted in a ketone structure and gradually redshift with the fluorescence intensity decreased;But at fw from 70%to 80%,due to molecular aggregation blocked the ESIPT and ICT processes,the fluorescence blue shifts and increases.This was proved by dynamic light scattering and refined water ratio growth experiments;And at fw from 80%to 100%,as the molecules became more and more flat,intramolecular hydrogen bonds gradually replaced intermolecular hydrogen bonds,and USC-001once again emitted fluorescence with a keto structure.The third chapter explores the ability and mechanism of the probe USC-001 to detect UO₂²⁺.USC-001 has a good recognition effect on UO₂²⁺in H2O:THF=95:5（V/V）,and in the ion selectivity and competitive experiments,except for Cu²⁺interference,other coexisting ions have no interference on UO₂²⁺detection,and Cu²⁺interference can also be masked by masking agent.In addition,the coordination ratio of USC-001to UO₂²⁺was estimated to be 2:1 by Job’s plot and density functional theory,and it was proved by FI-IR,¹H NMR and TOF-MS.According to the experimental results,O atoms from USC-001 and N atoms from dihydrothiazole are involved in the coordination,binding UO₂²⁺with a2:1 coordination ratio,resulting in molecular fluorescence quenching due to the PET mechanism.Finally,it has been successfully used to detect uranyl ions in water samples from Xiangjiang River and biological cells,providing a method for the detection of UO₂²⁺in actual environment and biological samples.