Design,Synthesis And Recognition Studies Of Fluorescent Probe For Hypochlorous

In biology,ClO^-was generated by reaction of hydrogen peroxide and chloride ion under the catalytic of myeloperoxidase in neutrophils.As an important oxidizing reagent,hypochlorous acid which has antibacterial properties plays an important role in the immune system.However,more and more evidence indicated that anomalies of hypochlorite level have important relationship with tissue damage,degeneration of neurons,cancer and cardiovascular disease.Therefore,it is crucial to find a method to detect hypochlorite with high sensitivity and good selectivity.Compared with traditional detection technology,fluorescent probe which is a new detection technology features easy operation,quick response and high sensitivity,as well as good selectivity,becoming a kind of essential detection tools in cell biology and medical field.The application of fluorescence labeling technology is closely related to the development of fluorescent probe.Among all kinds of fluorescent dyes,1,8-naphthalimide is widely used due to its high fluoresce fluorescent dye nce quantum yield,large stokes shift,stability,easiness to modify.Structurally,connection of electron donor to 4-position of 1,8-naphthalimide will lead to intramolecular charge transfer effect which could be used to design and synthesized fluorescence probe based on intramolecular charge transfer?ICT?mechanism.At the same time,we set out to develop some commercial fluorescent dyes directly applied to identification of ions or molecules,to make up for the disadvantages of traditional chemical probe such as complex of synthesis process,time-consuming,money-consuming and so on.This paper introduces three red fluorescent chemical probes.Probe 1 is a "turn-off"and colormetric probe which can be used for sensitively and efficiently detecting hypochlorous acid.Due to ON-OFF or OFF-ON probes measured at a single wavelength,which may be influenced by many factors such as instrument efficiency and environmental conditions,we designed and synthesized ratiometric probe 2 and 3 based on 1,8-naphthalimide.Through the experiments we found that probe 2 and 3 is selectively response toward hypochlorous acid,and recognition performance is excellent.Detailed as follows:1.Probe 1 has a strong red fluorescence(?_em = 625 nm)in aqueous solution,which could be quenched due to oxidization after addition of hypochlorite resulted in detecting of hypochlorite ion.This probe can also be used for biological imaging with a detection limit of 0.037?M.2.Probe 2 and 3 are 1,8-naphthalimide-based probes which were synthesized by reaction of salicylaldehyde derivative of 1,8-naphthalimide with indole or benzoindoles,respectively,in the ethanol.Spectrometric experiments were studied in HEPES/CH₃OH?1:1?solution.A series of experiments showed that these two probes can detect ClO^-not only via fluorescence spectra and ultraviolet visible absorption spectra,but also by visualizd color change of the solution from purple to colorless.The detection limits were 0.053?M for probe 2 and 0.076?M for probe 3,and these two probes successfully applied in cell imaging experiments.