Design, Synthesis And Application Of Red Light Materials With Aggregation-induced Luminescence Properties

In recent years,compounds with aggregation-induced emission(AIE)effects have drawed great attention in the fields of fluorescence detection,bioimaging,and organic light emitting diodes due to their special luminescence behavior and high solid quantum efficiency.However,most AIE compounds have shorter emission wavelength,and it is of great significance to broaden the emission wavelength of AIE compounds for the fileds of fluorescence detection and biological imaging.Based on the AIE effect and intramolecular charge transfer(ICT)process,a class of AIE compounds with red emission were synthesized and successfully applied to highly sensitive fluorescence detection and intracellular mitochondrial targeting probe.The main work is as follows:(1)A cationic compound(TPE-QN)with AIE effect was designed and synthesized by combining quinolinium salt with tetraphenylethylene(TPE)group.TPE-QN showed strong red fluorescence in DMSO/H2O(1:99,v/v)solution,and the fluorescence was significantly quenched when iodide was added.This is due to the strong electrostatic interaction between TPE-QN and iodide ions as well as the effective collisions between them.Other anions can not quenched the fluorescence of TPE-QN,so TPE-QN can be used as iodide ion fluorescent sensor,and the detection limit is 22.6 nM.When mercury ions were added into above system,the fluorescence of the system was enhanced due to the strong affinity between the mercury ions and the iodide ions,thus eliminating the quenching effect of iodide ions.Therefore,TPE-QN-I can act as mercury ion fluorescent sensor,and the detection limit can reach 71.8 nM.Since TPE-QN has a high sensitivity to iodide and mercury ions,it can be used for the successful detection of trace iodide and mercury ions in tap water and urine.(2)On the basis of TPE-QN molecular structure,another cationic compound TPE-QN-2 with AIE effect was successfully synthesized by increasing the number of double bonds,and the emission wavelength was redshift compared to TPE-QN.We further explored the application of these compounds in cell imaging.MTT assay showed that the two compounds show good biocompatibility.Further biological experiments suggested that the two compounds can stain in the mitochondria with highly specificity.In addition,under the irradiation of white light,these compounds can produce singlet oxygen,which make those AIE compounds have potential application in the field of cancer cell diagnosis and treatment.