Design,synthesis And Application Of Pyrazoline Structure Metal Ion Fluorescent Probes

In recent years,the detection and tracking of metal ions,especially transition metal ions,in organisms and environments has played a significant role in the field of chemistry and biological sciences,and it is also an effective means of protecting the environment.Fluorescent probes are widely used for the analysis and detection of metal cations,anions and neutral molecules due to their advantages of good selectivity,high sensitivity,low cost,and easy operation.Pyrazoline derivatives,as an important class of nitrogen-containing five-membered heterocyclic compounds,not only possess a wide range of biological activitie but also has good stability,good membrane permeability and low toxicity,and is widely used as fluorescent whitening agent,and detection metal ion fluorescent probes,hole transport materials,and the like.Currently,as a metal ion fluorescent probe,pyrazoline compounds have attracted the attention of many researchers.In this paper,three kinds of metal ion fluorescent probes were designed and synthesized based on the advantages of fluorescent molecular probes and pyrazoline compounds.The optical properties were studied and the probe was applied to intracellular detection.The specific work mainly includes the following four aspects:In chapter one,according to the related literature,the construction of fluorescent probes and several common recognition mechanisms are described.In addition,the definition of fluorescence,the factors affecting fluorescence,and the progress of research on pyrazoline fluorescent probes are briefly introduced.And thus put forward the design ideas and research topics of this paper.In chapter two,We have justified designed and synthesized a straightforward pyrazoline-based fluorescent probe,which displays specific responses with Zn²⁺and Cd²⁺ions in mixed buffer medium at physiological p H.Addition of Zn²⁺and Cd²⁺showed drastic enhancement of emission intensity,meaning that probe 1 could be used as a dual probe in ethanol aqueous solution for these metal ions.The probe 1formed a 1:1 complex with Zn²⁺and Cd²⁺which inhibit the C=N-N isomerization and generated complexation-enhanced fluorescence effect.The probe not only has low toxicity but also can be successfully applied to the microscopic imaging for detection of Zn²⁺and Cd²⁺in Hela cells.In addition,the 1-Zn²⁺and 1-Cd²⁺ensembles for subsequent selectivity for the PPi in the same medium.In chapter three,a novel highly selective fluorescent probe based on a pyrazoline monomer was synthesized and used for the determination of Zn²⁺ion with high selectivity and a low detection limit in ethanol aqueous solution.The probe L formed a 1:1 complex with Zn²⁺,which inhibits the isomerization of C=N-N and produced a complex enhanced fluorescence effect.The addition of PPi can quench the fluorescence of L-Zn²⁺,indicating that L is a reversible probe.The probe was successfully applied to the microscopic imaging for detection of Zn²⁺in BHK-21cells.In chapter four,a new pyrazoline fluorescent probe compound L₁ containing a quinone-naphthol system was designed and synthesized.Its specific response to Cu²⁺ions in a mixed buffer medium at physiological p H was studied.The addition of Cu²⁺significantly reduced the emission intensity,which means that probe L₁ can be used to detect Cu²⁺ions in aqueous ethanol.The addition of PPi restored fluorescence,indicating that L₁ is a reversible probe and can be used to detect PPi.