Synthesis Of Tetraphenylethylene Based Reactive Fluorescent Probes For Simutaneous Detection Of Formaldehyde And H₂S

Formaldehyde（Formaldehyde,FA）and hydrogen sulfide（H₂S）are toxic pollution gases,which have adverse effects on human health and can lead to death in serious cases.However,endogenous FA and H₂S participate in a variety of physiological and pathological processes,and play an antagonistic role in coordinating nervous system stability.The abnormal concentration of both these species can cause cancer,diabetes and degenerative neurological diseases.Therefore,the real-time,accurate and highly selective detection of FA and H₂S is of great significance for monitoring environmental quality and revealing the mechanism under diseases.Reactive fluorescent probes have been widely used in the detection of various analytes because of their high selectivity,high sensitivity,fast response,and the real-time and non-invasive detection potentials.In recent years,aggregation-induced emission（AIE）enhanced fluorescent probes have made up for the shortcomings of traditional aggregation-induced fluorescence quenching probes,and became a research hotspot.In this thesis,two reactive fluorescent probes with AIE properties were designed and synthesized for the detection of FA and H₂S,simutaneously.1.TPE-3NH₂ and TPE-4NH₂ were synthesized by introducing amino groups as recognition unit for FA on tetraphenylethylene（Tetraphenylethylene,TPE）.FA reacts with amino groups to generate imines,which can both reduce the solubility of fluorescent probes and inhibit the PET process,thus leading to the emergence of a new fluorescence emission peak at 526 nm.Both TPE-3NH₂ and TPE-4NH₂ have high sensitivity to FA,which showed the low detection limits of 9.3 and 4.5μM,respectively.In addition,fluorescent probes can be loaded on the TLC board for the semi-quantitative detection of FA.At the same time,the fluorescent probes also have good biocompatibility and can be used for the imaging of exogenous FA in living cells.2.Taking advantage of the redox reaction between Ag⁺and TPE-4NH₂ which can quench probe’s fluorescence of and lead to the formation of silver nanoparticles（Ag NPs）and oxidized probes（ox-TPE-4NH₂）,a fluorescence method was developed for the simultaneous detection of H₂S and FA.In the presence of H₂S with concentration less than the probe,ox-TPE-4NH₂ is partically reduced and leads to a slightly fluorescence recovery.When more H₂S is added,the excess H₂S reacts with Ag NPs and forms Ag₂S on Ag NPs,resulting in a significant increase in the fluorescence intensity.In the presence of FA alone,no fluorescence can be observed since it can not react with the oxidized probes.However,when FA and H₂S coexist,the reaction of FA with TPE-3NH₂ or TPE-4NH₂ can further enhance fluorescence,red-shift the fluorescence emission.At the same time,the signal is further enhanced by Ag₂S@Ag NPs,and the signal enhancement has close relationship with the H₂S content.Based on this phenomenon,the system can be used for the simultaneous detection of FA and H₂S.