Fluorescent Sensors For Cysteine And Fluoride Ion Based On Tetraphenylethylene AIE Molecules

Traditional fluorophores suffered from the aggregation caused quenching of fluorescence,which limited their application as fluorescent sensors and resulted in low detection sensitivity.While fluorophores with the unique aggregation induced emission?AIE?characteristics have attracted significant attention in recent years,and they have been widely studied as chemo-/bio sensors,fluorescence imaging and organic light-emitting materials.In recent years,tetraphenylethylene?TPE?compounds are attracting increasing interest as typical AIE fluorophores,due to its simple structure,ease of synthesis and modification.In this dissertation,two kinds of tetraphenylethylene based AIE fluorescent sensors were designed and synthesized for the detection of cysteine and F^-.The main research contents are summarized as follows:1)A tetraphenylethylene based sensor bearing a 2,4-dinitrobenzene sulfonyl group,TPENNO₂,was designed and synthesized.The electron withdrawing property of the 2,4-dinitrobenzene sulfonyl group makes TPENNO₂ non-emissive in aqueous solution.After reaction with the SH group in cysteine?Cys?,the 2,4-dinitrobenzene sulfonyl group was removed,resulting in highly emissive TPE derivative.The selectivity of TPENNO₂ toward Cys is far superior to other biothiols,such as homocysteine?Hcy?,glutathione?GSH?.Moreover,the cytotoxicity of TPENNO₂ is low and TPENNO₂ can be used to imaging intracellular thiols in living He La cells.2)A tetramethylidene derivative,MOTIPS-TPE,bearing one triisopropylsilane group appended to a cationic pyridinium group was designed and synthesized.MOTIPS-TPE exhibited some water solubility and showed low cytotoxcity toward He La cells.The fluoride promoted cleavage of the triisopropylsilane group subsequented with the spontaneous 1,6-elimination generated MOPy-TPE.MOPy-TPE has poor water solubility and tends to aggregated in aqueous solution.As a result,the fluorescence was turned on.MOTIPS-TPE was also applied in imaging of F^-in living He La cells.