Synthesis And Cell Imaging Applications Of Polyarylimidazole-Based AIE Fluorescent Dyes

In this dissertation,the aggregation-induced emission(AIE)properties of three kinds of polyarylimidazole derivatives were systematically studied.The key structural factors leading to aggregation-induced emission were discussed.And their applications in cell imaging were examined.The full text consists of four chapters,including the following contents:In the first chapter the development history and research progress of aggregation-induced luminescence were summarized.In the second chapter,the AIE properties of 2,4,5-triphenylimidazole derivatives were studied.Two butylidene bridged bisimidazole derivatives and two 1-butyl substituted monoimidazole derivatives were synthesized by using dibromobutane/bromobutane and 2,4,5triphenyl-1H-imidazole derivatives.All four of the imidazole derivatives showed excellent AIE properties.The research on AIE mechanism indicated that the restriction of twisted intramolecular charge transfer(TICT)was responsible for the AIE behaviors of these imidazole derivatives.Therefore,the strong electron-withdrawing group at 2-position is the key factor for their AIE activities.In addition,the steric effect of the substituent group at 1-position of imidazole ring is also indispensable for AIE.Finally,two monoimidazole derivatives were used for cell imaging.Both of them showed excellent fluorescence imaging performance in blue,green and red channels,but the different staining regions in cells were observed in different channels.In the third chapter,the AIE properities and cell imaging applications of 1,2,4,5tetraarylimidazole derivatives were studied.Two tetraphenylimidazole derivatives with propeller-like highly twisted conformation were synthesized from benzil,p-nitrobenzaldehyde and aromatic amines.Both of them showed excellent AIE properties.The cell staining and fluorescence imaging performance of self-assembled nanoparticles and F-127 encapsulated nanoparticles were compared.The self-aggregation nanoparticles and the pluronic F-127 encapsulated nanoparticles of them were prepared for comparative study of their cell imaging performance.The findings indicated that they showed the distinct staining behaviors.The cells stained with the self-aggregates showed clear cell outlines but fuzzy cell interiors.By comparison,the pluronic F-127 encapsulated nanoparticles can be distributed in the whole cell.In the fourth chapter,three tetraphenylimidazole derivatives containing aryl acrylonitrile group were synthesized.All of them showed good AIE properties in THF/H2O,and the emission intensities reached the maximum when the water volume fractions were 99%.All of them displayed an excellent bioimaging performance in blue,green and red channels,but the different staining regions in cells were observed in different channels.