Synthesis And Properties Of Water-soluble ONOO^- And HClO/ClO^- Fluorescent Probes Based On Aggregation-induced Luminescence

Peroxynitrite(ONOO^-)and hypochlorite/hypochlorite(HClO/ClO^-)are important reactive oxides in living organisms,which are essential for maintaining metabolic stability and causing diseases.Most of the current fluorescent probes for the detection of ONOO^-and HClO/ClO^-are synthesized based on conventional fluorophore design and are prone to fluorescence burst.In this paper,based on tetraphenylene fluorescent master with aggregation-induced luminescence properties,combined with polyethylene glycol chains with good water solubility,we designed and synthesized fluorescent probes to recognize ONOO^-and HClO/ClO^-,respectively,endowed with aggregation-induced properties and water solubility of the probes,and investigated their spectral properties and recognition mechanisms,respectively,as follows.In the first part of the work,the tetraphenylene fluorescent parent(TPE-NH₂)was firstly reacted with succinic anhydride by condensation reaction,and the synthesized tetraphenylene derivative TPE-COOH was reacted with polyethylene glycol 2000 and polyethylene glycol monomethyl ether 1900,respectively,to obtain the probes TPE-PEG2000-TPE and probe TPE-PEG1900.the probes were investigated by fluorescence spectrometry and UV The spectroscopic properties of these probes were investigated by fluorescence spectroscopy and UV-absorption spectroscopy,and the results showed that the probes have typical aggregation-induced fluorescence properties in the DMF/H₂O mixture,and have good selectivity for ONOO^-.The probe TPE-PEG2000-TPE showed a"turn-off"recognition of ONOO^-with a burst ratio of97.1%and a detection limit of 1.61×10^-5.The probe TPE-PEG1900 showed a"turn-on"recognition of ONOO^-with a fluorescence enhancement of 5 times."The difference in fluorescence may be due to the different grafting rates of polyethylene glycol groups on fluorophores in the probe molecules.The identification mechanism was investigated by thin-layer chromatography and ESI-MS,and it was hypothesized that the reaction between the probe and ONOO^-broke the ester bond to generate TPE-COOH,which caused the change in fluorescence.In the second part of the work,the tetraphenylene parent(TPE-CHO)was modified by cyanoacetic acid to obtain the compound CN-TPE-COOH with an increased conjugated structure,and the C=C double bond recognition site was introduced,which was condensed with poly(ethylene glycol)monomethyl ether 1900to obtain the probe CN-TPE-PEG1900.The spectroscopic properties of the probe were investigated,which showed that the probe was The spectroscopic properties of the probe showed that the probe exhibited typical aggregation-induced fluorescence properties in CH₃OH/H₂O mixture solution and good selectivity for Cl O^-.The probe CN-TPE-PEG1900 showed a"turn-on"recognition of Cl O^-with a 7-fold fluorescence enhancement and a detection limit of 1.7×10^-5,accompanied by a color change(yellow to colorless),which was investigated by thin-layer chromatography and ESI-MS,and the mechanism of recognition was hypothesized to be that the double bond between the probe and Cl O^-reaction broke the double bond to generate TPE-CHO,which caused the fluorescence change.