Synthesis And Application Of Fluorescent Probes Based On Bis-chalcone And Bis-pyrazoline

As a new detection method,fluorescent probe has attracted wide attention.Compared with traditional detection technology,it has the advantages of simple operation,low cost,strong selectivity,easy modification,real-time detection and easy visualization,it is widely used in environmental engineering,bioengineering and agriculture.At present,there is relatively little research work on fluorescent probes of bis-chalcone and bis-pyrazoline.Based on the excellent optical properties of chalcone and pyrazoline structures,this paper designed a bis-chalcone fluorescent probe to investigate the recognition effect of hydrazine.In addition,based on the cyclization reaction between chalcone and hydrazine,a fluorescent probe with bis-pyrazoline structure was synthesized to explore the recognition effect on metal ions.Four kinds of small molecular fluorescent probes X₁-X₄ with bis-chalcone structure were designed.The structure of probes X₁-X₄ was confirmed by ¹H NMR,¹³C NMR and ESI-MS.The optical properties of probes X₁-X₄ show that probes X₁-X₄have high selectivity for hydrazine in DMF:H₂O,（V/V=（9:1）HEPES,10 m M,pH=7.4）buffer solution,and have the advantages of fast response within 10 minutes,low detection limit and no influence of pH.In addition,gaussian quantization calculation and mass spectrometry analysis show that the interaction between probe and hydrazine lead to the closure of intramolecular ICT effect and fluorescence quenching.The cytotoxicity of probe X₄ on Hela cells and cell imaging tests showed that chalcone compounds had good biocompatibility and low toxicity,and could be used to detect hydrazine in cells.Three kinds of fluorescent probes Y₁-Y₃ with bis-pyrazoline structure were designed,and the molecular structures were confirmed by ¹H NMR,¹³C NMR and ESI-MS.The optical properties of probes Y₁-Y₃ show that probes Y₁ and Y₂ have the advantages of specific recognition for Cu²⁺and Fe³⁺in THF/H₂O（V/V=9:1,HEPES,10 m M,pH=7.4）,low detection limit,excellent anti-interference ability,and ion recognition is not affected by pH,Y₃ has no recognition effect on metal ions.In addition,the recognition mechanism of probe Y₁ for Cu²⁺and Fe³⁺was inferred by infrared spectrum test,gaussian quantization calculation and nuclear magnetic resonance study.The toxicity test and cell imaging test of probe Y₁ on He La cells show that the fluorescent probe with bis-pyrazoline structure has good biocompatibility and low toxicity,and can be used to detect metal ions in cells.A new fluorescent probe Z of bis-pyrazoline was synthesized.The molecular structure was confirmed by ¹H NMR,¹³C NMR and ESI-MS.The study of optical properties shows that probe Z has the advantages of enhanced fluorescence response,low detection limit and reusability to Zn²⁺in DMF/H₂O（V/V=9:1,HEPES,10 m M,pH=7.4）buffer solution.The recognition mechanism of probe Z for Zn²⁺was speculated by infrared spectrum test.