Triazole based ratiometric fluorescent probe for Zn2+ and its application in bioimaging.

An efficient fluorescent chemosensor 4-((2-hydroxynaphthalen-1-yl)methyleneamino)-3-phenyl-1H-1,2,4-triazole-5(4H)-thione, based on triazole has been designed by condensing 2-hydroxy-1-napthaldehyde with amine, appended to 1,2,4-triazole unit. The probe displays excellent selectivity and sensitivity in both absorbance and fluorescence detection of Zn2+ over other essential metal ions. The nature of fluorescence behavior of receptor upon addition of Zn2+ has been obtained from Density Functional Theory calculations. Imaging experiment indicates that probe works effectively for intracellular Zn2+ imaging with good cell permeability and biocompatibility.