Study On Synthesis And Properties Of 4-substituted 1,8-naphthalimide Organic Fluorescent Compounds

With the development of science and technology,the research on new materials is going deep.Acenaphthene,a compound with a high content of coal tar components,can be transformed into a new type of fluorescent naphthimide with high performance.Naphthalimides have been widely used in fluorescent probes,cell imaging and optical devices due to their excellent photophysical properties and easy modification.In order to explore the fluorescence properties of naphthalimide derivatives,six compounds with different fluorescence properties were designed and synthesized using C-4 as modification site after exploration and design,and their fluorescence properties were systematically studied.The research results are as follows:1.The synthesis of key intermediate 4-aldehyde-1,8-naphthalimide was optimized,which reacted with o-aminophenol in one step to produce BHBD which can specifically recognize Cu²⁺.The compound has high selectivity and sensitivity,and the detection limit of Cu²⁺is 4.8×10^-5M.It has shown excellent performance in the test of real water samples,and has been successfully applied to the cell imaging of He La cells,and can also recognize Cu²⁺in the cell field.2.Based on the fluorescence quenching properties of compounds 4-aldehyde-1,8-naphthalimide,the compounds ND-1,BHBD and ND-2 with the properties of ACQ,AIE and ESIPT were designed and synthesized.Taking compound ND-1 as the model compound,combined with compounds BHBD and ND-2,the fluorescence properties of the three compounds were mainly studied due to their different structures.It was found that the properties of ACQ could be changed from AIE through structural regulation.At the same time,due to the presence of hydroxyl group in the structure,ESIPT properties are also present.The comparison of fluorescence properties of the three compounds enables us to have a deeper understanding of ACQ,AIE and ESIPT.3.Based on the strong electron donating properties of benzimidazole,two fluorescent compounds NDB-1 and NDB-2 with high quantum yields were designed and synthesized.NDB-1 and NDB-2,by introducing the benzimidazole structure into4-aldehyde-1,8-naphthalimide,and changing their fluorescent properties,the effect of methyl groups in the structure of benzimidazole on the fluorescence properties of the compounds was also studied.It was found that both compounds have strong fluorescence quantum yields,which can reach more than 80%in solution,the presence of methyl group affects the conjugated structure of the compound,and then affects its fluorescence properties.4.Based on the mechanism of reactive fluorescent probes,an“OFF-ON”fluorescent probe NDC was designed and synthesized.The fluorescence test showed that the compound NDC has high selectivity and sensitivity to ClO^-,and its detection limit is as low as 67 n M,in the real water samples of ClO^-detection also have good results,and we successfully made a test paper can detect concentrations of ClO^-.There are 70 pictures,4 tables,and 116 references in this paper.