Synthesis And Properties Of Solvent-induced Structural Tautomeric Probes With Mitochondria/Lysosome Targetability

Using solvents to affect the structure,kinetics,and charge distribution of organic compound molecules,small molecular solutions can exhibit different colors.In recent years,solvent probes have good application in the fields of chemistry and biology.In addition,probes that can simultaneously target mitochondria and lysosomes are beneficial to explore the relationship between the pathological and physiological effects in different assays.As such,it is necessary to develop fluorescent probes that accurately locate mitochondria and lysosomes simultaneously for cell imaging in some disease diagnosis.HSO3-,as a derivative of SO2,has a certain harmful effect on human health and ecological environment.In this dissertation,we synthesized three solvent-induced structural tautomeric probes(PBIC-C,PAIC-C,PPIC-C),and explored their properties and applications.Furthermore,we also found that PBIC-C could be used as a colorimetric and ratiometric fluorescent probe with specific detection of HSO3-.The details are as follows:1.Three organic fluorescent probes PBIC-C,PAIC-C and PPIC-C were synthesized using 4-bromo-l-naphthocarbonitrile as the initial material.The probes exhibited diverse photophysical characterization(spectra,quantum yield and fluorescence lifetime)and distinct solvatochromic behavior in different polar solvents.In this regard,we carried out UV-vis spectra and nuclear magnetic titration experiments.Trace water was added dropwise to trichloromethane and dichloromethane of probes to observe the changes of UV absorption spectra and solution color respectively.Excess trifluoroacetic acid was added to the deuterated dimethyl sulfoxide of the three probes to observe the changes in the UV absorption spectra and 1H NMR spectra.Given all that,we speculated that the solvatochromism of three probes were all caused by the ground-state intramolecular proton transfer(GSIPT),that is,there were two reversible conversion isomers(spiro structure and double bond structure)in different solvents.In addition,cell imaging tests revealed that the designed probes could be used as dual intracellular mitochondria/lysosome-targeting fluorescent probes for biological applications.2.Compound PBIC-C could also be used as a colorimetric and ratiometric fluorescent probe for HSO3-.Based on the C=C nucleophilic addition reaction mechanism,the dual excitation fluorescence tests were performed with 350 nm and 520 nm as excitation wavelengths,and the fluorescence signal ratio I397/I646 increased by about 20 times.The linear range was 0.04-0.19 mmol/L,and the detection limit was 208 nmol/L.The color of the solution gradually changed from purple to colorless.Moreover,PBIC-C had good photostability and wide pH test range(4-8),and the specific detection of exogenous HSO3-in cells was demonstrated.