The Structure,spectrum Regulation And Application Of Retinal And Naphthalimide

Nowadays,organic fluorescent dyes have attracted great attention because of their diverse structure and functions and wide application range.Under the stimulation of common external factors such as light,electricity,heat,pressure,acid and alkali,fluorescent dyes can emit light with different wavelengths and change in absorption wavelength,or switch between fluorescent and non-fluorescent,different colors and reversible change.Retinal is a natural chromophore of conjugated polyene.Because of its biocompatibility and sensitivity to light,it has gradually become a research focus.4-Bromo-1,8-naphthalenedicarboxylic anhydride is a conventional fluorophore,which has the advantages of strong fluorescence,good stability,fluorescence quantum yield,and easy modification,therefore,it has been of important research value.This article discusses the synthesis,properties and potential applications of retinal and naphthalimide fluorescent dyes in four chapters.Chapter 1:The principles,characteristics and influencing factors of the absorption and fluorescence spectra of substances are reviewed,and the research status of retinal and naphthalimide in various fields is introduced.Chapter 2:Retinal has a flexible chain structure and natural biocompatibility.It can be used as a fluorophore for fluorescent probes from solvent environment to physiological environment,but it is rarely used for fluorescent probes due to its poor fluorescence performance.Therefore,we designed and synthesized a new Cu²⁺fluorescent probe using retinal as a chromophore and o-phenylenediamine as a chelator.The study found that the probe can be used as a Cu²⁺selective and sensitive sensor.After combining with Cu²⁺in acetonitrile,its ultraviolet absorption spectrum and fluorescence emission spectrum show regular changes,and it has strong anti-interference ability to other common cations.In addition,the probe can also function in saline and serum.Chapter 3:Natural retinal derivatives are able to respond to different wavelengths of light by regulating different protein environments.Therefore,it is important to explore or simulate the photochemical and photophysical properties of retinal in abiotic systems.We introduce different push-pull electron groups at the ends of retinal:malononitrile,diaminomaleonitrile,and o-phenylenediamine.These groups replace proteins to regulate the charge distribution of retinal.Studies have found that in the absence of a protein environment,retinal derivatives achieve susceptible reactions to visible light through cis-trans isomerization,protonation,and deprotonation.The response mechanism similar to that in the protein environment has been confirmed by copper ion coordination.A preliminary application experiment of retinal-o-phenylenediamine was also carried out,which was used for information security verification.Chapter 4:Classical tautomer proton transfer is usually limited to adjacent groups within the molecule.The contrast of the tautomers’structure and physicochemical properties is not enough.Therefore,we proposed a long-range question transfer strategy and designed and synthesized a series of proton tautomers N1-N5 based on the naphthimide chromophore.The isomerization of N1-N5 in the presence of different solvent polarities and fluoride ions was studied.The general structure of naphthalimide based on long-range proton tautomers was established.A high contrast isomer with an absorption change of more than 200nm was developed.By changing the solvent polarity and fluoride titration,the long-range proton tautomerism activity of N1-N5 was further verified.The structural transfer of tautomeric isomers is characterized by NMR.