Synthesis, Structure And Application Of BODIPY-type Cu²⁺ Fluorescent Probe

Fluorescent probes are widely used in chemistry,medicine,food analysis,disease treatment and other fields due to their advantages of high sensitivity,short response time,easy operation,real-time and in-situ detection,etc.In order to overcome background interference and enhance the penetration depth in biological samples(or in vivo),long wavelength fluorescent probes which feature near infrared exciting and emitting wavelengths have attracted much attention in recent years.BODIPY dyes are undoubtedly excellent candidates in all short wavelength sensitizing dyes for its excellent properties,such as high fluorescence quantum yield,high molar absorption coefficient,easy functionalization and excellent light stability.Based on BODIPY,the following work has been carried out in this thesis.(1)Novel compounds BC-DPA and BA-DPA with BODIPY as fluorophore and dimethylpyridinium(DPA)as Cu²⁺recognition group were designed and synthesized.The intermediates and target compounds were systematically characterized by mass spectrometry and nuclear magnetic resonance spectroscopy.Additionally,the crystal structures of BA and[Cu^?(BC-DPA)](Cl O₄)₂(H₂O)are determined by X-ray single crystal diffraction,which belong to monoclinic P2₁space group and triclinic P-1spacegrouprespectively.Thesinglecrystalstructureof[Cu^?(BC-DPA)](Cl O₄)₂(H₂O)shows that BC-DPA combined to Cu²⁺with the ratio of 1:1 and forming a mononuclear copper complex with hexahedral and octahedral configuration.(2)BC-DPA is a good"turn-OFF"type copper ion fluorescent probe due to its good selectivity and sensitivity to Cu²⁺.The detection limit of BC-DPA towards Cu²⁺in HEPES-CH₃CN(19:1,V/V,10 m M,p H 7.4)buffer solution is 0.35?M,and the binding constant K_assis 4.66×10~5M^-1determined by fluorescence titration.(3)The fluorescence of BC-DPA almost completely quenched when treated by Cu²⁺,then the fluorescence recovered after hydrogen sulfide was introduced into the solution of BC-DPA-Cu²⁺companied by the generation of copper sulfide precipitate.Consequently,BC-DPA-Cu²⁺could be a prominent"turn-ON"fluorescence probe target hydrogen sulfide.(4)BC-DPA succeed in fluorescence imaging of Cu²⁺in living cells such as He La and MCF-7 on the premise of low cytotoxicity and good cell membrane permeability.BC-DPA is mainly distributed in cytoplasm and the green fluorescence can effectively be quenched by exogenous Cu²⁺in living cells.(5)Based on the phenomenon of obvious blue shift and hypochromic effect in UV-visible absorption spectra,we can conclude that BC-DPA-Cu(?)insert the base pairs of CT-DNA distinctly through non-classical intercalate combination mode.