| In the tide of technological innovation,the development and innovation of new materials provide support and convenience for people's lives and advances in science and technology.While searching for new materials,efficient and effective use and transformation of existing rich resources is also a topic that is worthy of further study.As an enriched product in coal tar,acenaphthene shows the potentialities in fine chemical processing and directed transformation use.Its conversion product,naphthalimide,is a good fluorescent chromophore,which has been widely used in the fields of molecular fluorescent probes,cell imaging and optical devices.In this paper,a series of organic fluorescent compounds were synthesized by directed modification of naphthalimide precursors,and the relationship between the structure of six compounds and the ESIPT luminescence properties was studied.The main research contents are as follows:1.Aldehyde group and hydroxyl group were introduced into the naphthalimide to increase the water solubility of the compound,and at the same time,the essential conditions for the proton transfer in the excited state molecule were constructed.BHC solids exhibited a rare photochromism property,and BHC's photobleaching resistance and stability were verified by fluorescence spectroscopy.The introduction of two hydrophilic groups successfully assisted the compound in cell imaging application and hypochlorite detection.As a probe,the detection limit could be as low as 1.16×10-8 M and the stability at physiological pH range,the selectivity in different ion mixed solutions,as well as cell imaging and endogenous hypochlorite detection were well characterized.2.N-1,N-2,N-3 of three Schiff base compounds were designed and synthesized.Optimized configuration and energy level orbit calculation,solvation and photophysical properties,different water contents fluorescence spectra,fluorescence quantum yields and fluorescence enhancement mechanism speculation explained the intermolecular hydrogen bonding of solvents and solutes that enhanced mechanism of H-bonding activates ESIPT.From N-1 to N-3,the design of the conjugate structure was increased.The Gaussian calculation also reflected the decrease of the energy band gap,and the accuracy of the design was confirmed by UV absorption.The results show that solution there was no fluorescence emission in non-aqueous solution.After the addition of water,the fluorescence increased several times with time,and the fluorescence quantum yield also increased several tens of times.The fluorescence quantum yield of a 50%water content solution of N-1 after standing for 24 hours is as high as 51%.These three compounds maintain high fluorescence intensity in higher water content solutions,which provides a reference for organic light-emitting materials in cell and tissue imaging applications.3.The benzimidazole and benzothiazole heterocycles with electron-withdrawing properties were designed to synthesize the compounds N-N and N-S.The properties of the proton transfer in the excited state were used to expand the planar size and conjugate size of the compound to change the luminescent properties of the compound.Characterization of the photophysical properties of the two compounds and the fluorescence of the different water contents revealed that the luminescent properties of the two compounds sharing similar structures were almost the same.The red shift of ultraviolet absorption and fluorescence emission in a protic solvent could be confirmed by the conformational change calculated by Gauss theory and the expansion of the conjugate plane.Both compounds could detect trace amounts of organic amines in organic solvents.The article tested the ability of two compounds to detect three amines:n-butylamine,ethylenediamine,and triethylamine,which are common in the industry and pose a threat to human health.The detection limits of the compounds N-N and N-S for the three amines were:9.9×10-8 M,6.5×10-8 M,9.4×10-7 M,5.4×10-8 M,9.2×10-8 M,7.8×10-8 M.This test was completely applicable to the standards of industrial production and human's daily life. |
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