Fluorescence Resonance Energy Transfer?Ions Detection And Applications Of Boron-dipyrromethene Based Dendrons

Here,a series of fluorescent probes were designed and synthesized based on fluoroboron dipyrrole?BODIPY?.Click reaction was used to connect BODIPY with other fluorophores like naphthalimide,rhodamine and xanthene fluorophore.In this work,several multi-channel ratio fluorescent probes were obtained.These probes can detect special species based on different recognition mechanisms using multi recognition groups.Probes reported in this work possessed many excellent properties like intramolecular fluorescence resonance energy transfer,near infrared emission,two-photon fluorescence and so on.These probes are capable of selectively identifying specific targets including cations,reactive oxygen species?ROS?,and reactive sulfur small molecules.Herein,the fluorescence properties and detection mechanism of these probes are studied and analyzed in detail.The following is an overview of this dissertation:Chapter 1:Summarizing the development process as well as advantages of fluorescent probes.Generalizing the mechanism of fluorescence.Introducing the design methods of some fluorescent probes and the transmission mechanism of fluorescent signals in detail.The application fields and development status of fluorescent probe molecules are summarized.The excellent properties of BODIPY fluorescent probes are introduced,and the design ideas of this dissertation are presented.Chapter 2:In this chapter,two fluorescent molecules NP-BODIPY and NPI-BODIPY were synthesized based on naphthalimide and fluoroboron dipyrrole.NP-BODIPY can realize the fluorescence resonance energy transfer?FRET?.Click chemistry?1,3-dipolar cycloaddition reaction?was used during the molecular construction process,which is an effective way to interconnect different fluorophores with high yield.During the research process,finding that NP-BODIPY possess the property of aggregation-induced fluorescence,and the solid NP-BODIPY has a purple-red fluorescence under ultraviolet light in a dark room.Besides,the study also found that dendron compound NPI-BODIPY can selectivity detect the Hg²⁺using wo triazole ring linkages,which demonstrate that the two triazole rings can form an effective metal chelate site for selectivity binding with Hg²⁺.For the purpose of improving the solubility of fluorescent dyes,the fluorescent nanoparticles were prepared by the normal phase microemulsion method,which improved the dispersibility of the fluorescent dyes in aqueous solution significantly.This is an effective way to broaden the application prospects of fluorescent dyes in many fields.Chapter 3:Two fluorescence-enhanced dendritic ratio-type fluorescent probes RhB-BODIPY and RhB-BODIPY-OH were constructed by Click reaction based on rhodamine and fluoroboron dipyrrole.The compounds were characterized by ¹H NMR,¹³C NMR and high resolution mass spectrometry.Probe RhB-BODIPY can realize the fluorescence resonance energy transfer?FRET?induced by proton as well as cation with fluoroboron dipyrrole?BODIPY?serve as energy donor and rhodamine play the role energy acceptor.The energy transfer efficiency reaches a high level.Probe RhB-BODIPY enables unique and efficient identification of Hg²⁺ions.In addition,probe RhB-BODIPY-OH can detect Fe³⁺and Hg²⁺ions,and the recognition process of both two probes can be visualized by naked eyes.RhB-BODIPY-OH has a low detection limit because of Probe RhB-BODIPY-OH is a multi-channel probe with 4 detection sites.Finally,RhB-BODIPY and RhB-BODIPY-OH was successfully applied to live cell imaging and exogenous ion recognition in live cells.Chapter 4:Two novel dendritic fluorescent probes TPA-BODIPY and TPA-BODIPY-OH were designed and synthesized based on triphenylamine fluoroboron dipyrrole.These two probes have high selectivity and low detection limit toward Fe³⁺and Hg²⁺ions.On the basis of TPA-BODIPY,p-hydroxy benzaldehyde was conjugated with BODIPY to extend the?conjugated structure of BODIPY fluorophore,and a near-infrared emission fluorescent probe TPA-BODIPY-OH was obtained.TPA-BODIPY-OH has three maximum emission wavelength.Probes TPA-BODIPY and TPA-BODIPY-OH were multi-channel ratio fluorescence probe with multi detection sites.Considering the detection mechanism,the fluorescence of BODIPY part was quenched due to the photoinduced electron transfer?PET?effect before recognizing the ions.When reacting with the Fe³⁺and Hg²⁺ions,the Schiff base C=N double bond was broken and form a C=O double bond,which lead to the fluorescence turned on.The detection process of both two probes have high stability under physiological environmental.Chapter 5:Compared with the probes described in above chapters,the fluorescent probes designed in this chapter are take full advantages of the probes described above.In this chapter,a two-photon near-infrared dendritic fluorescent probe NRhB-BODIPY was constructed based on near-infrared rhodamine.The probe NRhB-BODIPY has a great improvement in photophysical properties.Firstly,two-photon fluorescence emission is realized.NRhB-BODIPY can detect Hg²⁺ions under two-photon emission conditions.Secondly,the fluorescent probe realizes long-wavelength near-infrared fluorescence emission.Thirdly,the fluorescent probe maintains low low detection limit of rhodamine-based fluorescent probe.Finally,probe NRhB-BODIPY realizes the multiple cycles of utilization,and the"on-off"of the fluorescent signal can be repeatedly performed for several times.This probe has a great application prospects in the field of biological and optoelectronic materials.Chapter 6:In this chapter,a novel two-photon near-infrared emission active oxygen probe?NCS-BOD-OCH₃?was developed and synthesized,which can selectively detect the ClO^-.The detection mechanism of the probe NCS-BOD-OCH₃ utilizes the mechanism of desulfurization and cyclization of thiourea under ClO^-oxidation.The reaction is a ClO^-induced redox reaction,and the changes of fluorescence signal before and after the reaction is used to quantitative detection of ClO^-.Chapter 7:Herein,a red emission reactive thiol probe?RFP?was obtained by chemical modification of bioluminescent molecule green fluorescent protein?GFP?mimic.Probe RFP possessed many excellent properties of fluorescent protein-based mimic,such as good biocompatibility,large Stokes shift,stable photophysical properties,good anti-interference ability and so on.These properties can improve the properties and application fields of probe RFP.RFP is capable of selectively recognizing cysteine?Cys?.Normally,it is difficult to distinguish Cys,Hcy and GSH from the detection process because of cysteine?Cys?,homocysteine?Hcy?and glutathione?GSH?have similar structures and reactivity.However,RFP can selectively detect the Cys,Hcy and GSH using the different reaction time between recognition group acryloyl chloride and these reactive thiols.Chapter 8:Conclusion of this dissertation.