A benzothiazole-based fluorescent probe for distinguishing and bioimaging of Hg2+ and Cu2+

A new benzothiazole-based fluorescent probe 2-(benzo[d]thiazol-2-yl)-4-(1,3- dithian-2-yl)phenol (BT) with two different reaction sites, a thioacetal group (site 1 for Hg2+), and 0 and N atoms of the benzothiazole dye (site 2 for Cu2+), was designed and synthesized. The probe BT showed ratiometric fluorescent response to Hg2+ and fluorescence quenching behavior to Cu2+, which induces naked-eye fluorescent color changes from green to blue and colorless, respectively. Moreover, it displayed highly sensitivity and selectivity toward Hg2+ and Cu2+ without interference from other metal ions. The sensing mechanisms were also confirmed by H-1 NMR titration, mass spectrum and Job's plot analyses. Finally, probe BT was successfully used for fluorescent imaging of Hg2+ and Cu2+ in living cells, demonstrating its potential applications in biological science. (C) 2016 Elsevier B.V. All rights reserved.