Design,Synthesis And Properties Of Nitrozole Heterocyclic Dyes And Fluorescent Probes

In the past few decades,the important value of organic aromatic heterocyclic compounds based on theory and practical application has attracted wide attention from researchers.Among them,pyridone,pyrazolone,pyridinetriazole and other nitrogen-containing heterocyclic compounds have structural diversity and photoelectric properties,and have always been a research hotspot in various field.This article focuses on the design and synthesis,crystal structure,spectroscopy properties,and structure-activity relationship of the nitrogen-containing aromatic heterocyclic compounds pyridone,pyrazolone and pyridinetriazole dyes.The main content includes the following two aspects:（1）An asymmetrical pyrazolone/pyridone bi-heterocyclic dye was synthesized showing good solubility in both water and organic solvents.This dye has three possible azo/hydrazone tautomers because multiple N and O heteroatoms in its molecular structure could serve as the protonated sites for two active protons.NMR techniques have been used to deduce its specific configurations in different solvents,and the results reveal that it adopts monohydrazone in pyridone with5-OH-pyrazolone form in Me OH and double-azo form in water.The following solvatochromic and acid-base titration experiments verify the transfer of proton sites within the multiple heteratoms for the dye and the configurational alterations in non-aqueous and aqueous solvents.Furthermore,two distinguishable one-dimensional copper（Ⅱ）and nickel（Ⅱ）dye-metal coordination polymers have been obtained and structurally characterized.（2）A coumarin schiff base fluorescent dye CPTH modified with pyridinetriazole was successfully designed and synthesized,and NMR,FT-IR,and ESI-MS was used to characterize it.The crystal structure of the compound was further charaterized by X-ray single crystal diffractometer.The selective recognition effect of the probe on some common transition metal ions was systematically studied.The results of fluorescent spectrum analysis showed that the probe emitted strong yellow fluorescence in DMF/PBS（10 m M,p H=7.40,v/v=1/9）buffer solution,and the solution fluorescence was qunenched rapidly after the addition of Cu²⁺.Ultraviolet titration analysis showed that the maximum absorption wavelength was red-shifted from 449 nm to 475 nm.The results of fluorescence titration analysis showed that the probe has no selective recognition effect on other common metal ions selected in the experiment except Cu²⁺.The experimental results showed that the probe has fast response and selection specificity to Cu²⁺.The result of Job’s plot showed that the stoichimetry ratio between the probe and Cu²⁺was 1:1.At the same time,the detection limit of CPTH for Cu²⁺was calculated to be 2×10^-6M,which was obtained by linear fitting of Cu²⁺and probe.