Design,Synthesis And Performance Research Of Carbazole Derivatives Containing Cyanovinyl Unit With Aie Characteristics

The excellent electron donating ability and large conjugated coplanar molecular structures of carbazole endow carbazole fluorescent materials with special optical properties,such as active electron transfer ability,large Stocks shift and photostability.With all these advantages,carbazole moiety is usually used in the synthesis of many fluorescent compounds as the intermediates.But the aggregation caused emission quenching(ACQ)effect has been a great obstacle to the development of carbazole derivative fluorescent materials and has limited the application scope of the solid-phase materials.The discovery and study of aggregation-induced emission(AIE)provide a promising solution to the obstacles in this field.At present,carbazole derivatives with AIE properties have shown potential value for biological probes,fluorescence sensors and OLED components.However,their properties and types still cannot meet the growing needs for fluorescent materials,therefore,develop more kinds and better properties of carbazole derivatives with AIE performance are very important.Based on the above purposes,we have successfully synthesized 21 carbazole derivatives and the related compounds containing cyanovinyl units with AIE properties.Furthermore,their optical properties and AIE behavior were be researched also.Chapter 1:This chapter systematically summarizes the concept,mechanism,molecular design and application of AIEgen,and briefly introduces the design and synthesis of carbazole derivatives with AIE in recent years and their applications in various fields.Chapter 2:In order to endow the synthesized carbazole derivatives and the related compounds with excellent optical properties and AIE properties,Target compounds are synthesized by bonding carbazole as the electron-donating group with the typical AIE block of cyanovinyl unit.We selected carbazole and the like as raw materials to synthesize a series of 21 carbazole derivatives and related compounds with AIE properties which 19 have not been reported in literatures,by means of N-alkyl/arylation,friedel-crafts acylation and Knoevenagel condensation,structures of compounds were characterized by NMR,IR,HRMS and X-ray crystallography.The affect factors on acylation reaction such as solvent dosage,molar ratio of reactants,reaction temperature and time had been surveyed using single factor method,and then the optimal condition was obtained.Chapter 3:Many characterization such UV-vis absorption spectra,fluorescence emission spectra and dynamic light scattering(DLS)were used to explore the optical properties and the aggregation-induced emission behaviors of these 21 synthesized compounds.Experiment results showed that these compounds have excellent AIE properties,and the solid fluorescence emission wavelength is in the range of 502 ～ 595 nm.It can be found from experiment results that the fluorescence emission wavelength and intensity will be affected by the crystal form of compound18.Finally,relationships between the optical properties and the molecular structure of these compounds were analyzed by theoretical calculation and supplementary analysis of crystal structure.According to above experimental results,it can be draw that aggregation-induced emission occurs under the two mechanisms: the formation of J-aggregates and the restriction of intramolecular motion due to these compounds possessing highly distorted molecular structure.