A novel Bodipy-based fluorescent probe for Au3+ ions with high selectivity and its application to bioimaging

A novel fluorescent probe based on a boron dipyrromethene (Bodipy) derivative for Au3+ has been designed, synthesized, and characterized. The probe comprises a spectroscopic unit of Bodipy and a specific Au3+ binding unit of 2-(phenylethynyl)aniline. The probe itself is almost no fluorescence because of photo-induced intramolecular electron transfer from the aniline unit to the Bodipy moiety, whereas transforming the 2-(phenylethynyl)aniline unit into the 2-phenylindole by Au3+ induced intramolecular cyclization reaction gives rise to strong fluorescence emission. In the system, an excellent selectivity toward the detection of Au3+ in aqueous solution over a wide range of tested cations was observed. Moreover, this probe can be used to detect Au3+ in real water samples, and can be used for fluorescent bioimaging of Au3+ in living cells.