Design And Synthesis Of Cu~+ Fluorescent Probe With Azacrown Sulfide As Recognition Group And Imaging Of Cu~+ Detection

Fluorescence molecular detection imaging is a new molecular imaging technology.Its outstanding feature is the non-invasive qualitative or quantitative visual real-time observation of molecular events that participate in physiological and pathological processes in vivo.It is currently internationally recognized to carry out molecular events in vivo.One of the mainstream methods of event research has great application value in many fields such as physiological metabolism,early disease diagnosis,new drug development and drug efficacy monitoring.Copper is an essential trace metal element whose content in organisms ranks third after iron and zinc.The copper element exists in two forms of reduced monovalent copper ions and oxidized divalent copper ions in biological systems.At the same time,the two forms of copper ions can be converted into each other.Due to the proper redox properties of copper ions,it is a cofactor with many important proteases and plays an important role in physiological activities.Disorders of copper ion metabolism will cause a variety of diseases.Therefore,the detection of copper in biological systems is of great significance for understanding the physiological functions of copper ions and their role in pathology.Fluorescent probes are the core of fluorescent molecular detection imaging technology.In this thesis,based on the specific coordination properties of the crown ether structure for metal cations,a class of cuprous ion fluorescent molecular probes with azacrown sulfide as the recognition group was designed and synthesized,They are applied into the copper ion in living cells Fluorescence detection imaging,the specific content is as follows:1.Design,synthesis and route optimization of azacrown sulfide.The structure of three-unit crown sulfide is difficult to control.In this thesis,by controlling the nucleophilicity of the base in the reaction system,the concentration of the reactants and the order of addition of the reactants,the three-unit structure azacrown sulfide was successfully synthesized in one step.And by extending the reaction time and increasing the reaction concentration of the inorganic base,the yield of the three-unit structure of azacrown sulfide was increased from 5%to 27%,which was a 4-fold increase.2.Synthesis and characterization of Naphthalimide fluorescent probes with azacrown sulfide as Cu（Ⅰ）recognition group.In this thesis,by introducing azetidine into the 4-position of1,8-naphthimide,the formation of twisted intramolecular charge transfer（TICT）was suppressed,and naphthalimide fluorescence with excellent photophysical properties was prepared.The probe Nap-1 has a fluorescence quantum yield as high as 90%.The azacrown sulfide cuprous ion recognition group was further coupled with naphthimide to prepare Nap-2,a fluorescent probe that specifically recognizes cuprous ions.The probe Nap-2 has a fluorescence enhancement response characteristic,and its fluorescence intensity is increased by3-fold after binding with cuprous ions.3.Design of a Si-rhodamine fluorescent probe with azacrown sulfide as the recognition group and Cu（Ⅰ）detection and imaging.The Si-rhodamine was coupled with the azacrown sulfide cuprous ion recognition group to prepare a near-infrared fluorescent probe Si R-1 that specifically recognizes cuprous ions.The study of fluorescence properties showed that the maximum absorption peak of Si R-1 in PBS solution was at 661 nm,the maximum emission peak was at 685 nm,the molar absorption coefficient was 8.81×10⁴ M^-1cm^-1,and the fluorescence quantum yield was 7%.When combined with cuprous ions,the luminescence intensity of Si R-1 was significantly enhanced,and the fluorescence quantum yield increased to29%,which was a 4-fold increase,indicating that Si R-1 can achieve enhanced fluorescence detection of cuprous ions.Stability experiments show that Si R-1 has good chemical stability and light stability,which is conducive to long-term imaging in complex environments.Live cell fluorescence imaging experiments show that the probe Si R-1 is localized in cell mitochondria and can detect the dynamic changes of cuprous ions in live cell mitochondria.