A turn-on chemosensor based on naphthol–triazole for Al(III) and its application in bioimaging

A new Schiff base 1-[(1H-1,2,4-triazole-3-ylimino)-methyl]-naphthalene-2-ol (H2L) exhibiting high selectivity for Al3+ ion over other metal ions, such as Li+, Na+, K+, Ca2+, Mg2+, Cu2+, Co2+, Mn2+, Ni2+, Zn2+, Cd2+, Pb2+, Fe3+, and Cr3+ was prepared, and it is sensitive for Al3+ with the detection limit reaching 0.69 μM in DMF. Upon addition of Al3+, the significant enhancement (32-fold) of fluorescence intensity for H2L at 466 nm is ascribed to the formation of a 1:1 complex between Al3+ and H2L, which is denoted as the chelation-enhanced fluorescence (CHEF) effect. The confocal fluorescence microscopy experiments demonstrate that H2L could be used as a fluorescent probe for Al3+ in living cells.