A new “on-off-on” fluorescent probe containing triarylimidazole chromophore to sequentially detect copper and sulfide ions.

A novel compound TPI-H containing triphenylimidazole chromophore is synthesized and employed as fluorescent probe for sequential detection of Cu 2 + and S 2 − . With three binding sites in its molecular structure, TPI-H exhibits highly selective binding towards Cu 2 + and results in an apparent fluorescence “on-off” behavior. Fluorescence intensity is linear with the Cu 2 + concentration, and the detection limit can be down to 8.7 nM. Furthermore, the in-situ generated ensemble between TPI-H and Cu 2 + (TPI-H-Cu(II)) can be used to detect S 2 − with a low detection limit of 15.6 nM through Cu 2 + displacement method. In addition, the potential utility of the probe for the detection of Cu 2 + and further S 2 − in biological system is investigated by cell imaging. [ABSTRACT FROM AUTHOR]