Synthesis And Property Studies Of Schiff-base Fluorescence Probes Containing Nitrogen Heterocyclic Compounds

More and more researchers focus on the development of Schiff-base fluorescence probes with high selectivity,sensitivity,low detection limit and real-time monitoring.In view of previous researchers,we find Schiff-base fluorescence probes containing C=N structure with a lone electron pair have good ability to coordinate with metal ions.Compounds with an unbridged C=N structure are often nonfluorescent due to the C=N isomerization.By combining specific metal ions,the C=N isomerization is prevented,specific chelating effect is caused,thereby fluorescent property is enhanced.Therefore,we incorporated a special functional groups(–CH=N–)into our probe design.(1)Two novel Schiff-base fluorescence probes based on triazole and benzotriazole were designed and synthesized.Corresponding orbital electron distribution and molecular geometry configurations of the compounds were predicted by density functional theory(DFT).Fluorescence properties of probes were detected by UV–Vis and fluorescence spectra.(2)Two new Schiff-base fluorescent probes based on indole derivatives and4-aminoantipyrinewere designed,synthesized and characterized.Their characters toward metal ions have been studied by UV-Vis absorption spectra,fluorescence spectroscopy and electrochemistry.The stoichiometric ratio,detection limits and binding constant of compounds were obtained by the method of fluorescence titration.In addition,the optimized geometry and related properties were calculated at B3LYP/6-31G* by density functional theory.Innovation point in this paper:Four novel Schiff base fluorescent probes have been prepared,which have good selectivity for some special metal ions.