Study On The Structure-activity Relationship And Application Of Boron Difluoride β-diketone Dye

The novelπ-conjugated organic small molecules with excellent optical properties have broad application prospects in fluorescent dyes,probes,two-photon materials,and many other fields.Curcumin is the most common conjugatedβ-diketone compound.In recent years,the research on curcumin and its analogs boron-fluorine complexes is gradually becoming one of the research hotspots.Therefore,starting from the molecular structure in this paper,we discuss the asymmetric system related to curcumin but containing only half of theπ-conjugated main chain.and their interactions with biological macromolecules.The first chapter briefly describes the research progress of the fluorescence mechanism,curcumin and its fluoroboron complexes and serum proteins,and focuses on the application of curcumin and its fluoroboron complexes in various fields.Analogue boron-fluoride complexes are limited in structural diversity.In addition,albumin fluorescent probes with different luminescence types and their recent research results are introduced.Based on this,the research content and research purpose of this paper are put forward.The research work in the second chapter includes the synthesis and characterization of boron difluorideβ-diketone complexes,the determination of optical properties,and the application of cell imaging.A large number of literatures have previously shown that the spectrum of boron difluorideβ-diketone dyes can reflect the fine structure of the dyes,but so far,based on the molecular symmetry,based on its photophysical properties,the correlation of the structure-activity relationship of such dyes has not been explored.report.Therefore,this paper uses molecular symmetry to reveal the change law between molecular structure and properties.Our research shows that the characteristic absorption peaks of this series of compounds are mainly generated by theπ-π^*transition of the benzene ring or aromatic amine ring group in the molecule,and the molecule containing the aromatic amine group has stronger electron donating ability and larger conjugated system.The intramolecular electron density increases,and the solution fluorescence exhibits typical intramolecular torsional charge transfer（TICT）characteristics.In addition data integration is performed on the synthesized molecules,and it is found that with the increase of the power supply intensity of the group,the absorption and emission of the molecule are both higher.gradually red-shifted,indicating that the emission wavelength can be tuned by controlling the intensity of the terminal donor group.Due to the hydrophobicity of the arylamine group,it is embedded in the hydrophobic core of the lipid droplet through the strong hydrophobic interaction,and we also obtained the probe N-BF₂ that can specifically recognize the lipid droplet.With the continuous development of fluorescent labeling technology,protein tags covalently linked according to genetic codes have been developed,such as the widely used SNAP-tag,Halo-tag,but how to realize molecular recognition and activate fluorescence is still such fluorescent probes a challenge.The third chapter of this paper can explain the binding mode of small molecules with different structures and biological macromolecules at the molecular level through the binding of the commonly used model proteins in medicine-bovine serum albumin/human serum albumin（BSA/HSA）to small molecules.and fluorescence response mechanisms.The study found that based on the good optical properties of the small molecule probe N-BF2 and its sensitive response to changes in the microenvironment,it was combined with the biological macromolecule serum albumin.The binding of the two homologous serum albumin BSA/HSA（5μM）can achieve a 112/90-fold enhancement within 1.2 s.Surprisingly,this is the probe with the fastest recognition speed.Molecular docking shows that N-BF2 can be combined in HSA through hydrogen bonding and hydrophobic interaction,which further confirms that the aniline group connected by methyl bridge is crucial in the process of biological macromolecular recognition,so N-BF2 can be used as an ideal albumin recognition probe It led us to deeply understand the transport,distribution and metabolism of small molecule drugs in cells.We also discovered the process of the molecule entering and exiting lipid droplets through cell imaging,which is important for revealing the mode of action between drugs,antibodies,other functional molecules and lipid droplets,elucidating the mechanism of action of drugs,new drug transformation,and pharmacokinetics.data support.