Design of turn-on fluorescent probe for effective detection of Hg2+ by combination of AIEE-active fluorophore and binding site

By combination of the AIEE-active fluorophore and coordination binding group, a new selective and sensitive probe (1) for Hg2+ detection has been synthesized. 1 exhibits weak fluorescence in dilute solution, but exhibits dramatically enhanced emission in aggregation. In the solid state, a remarkable red-shifted emission and longer PL lifetime of 1 are present, which is caused by the formation of excimers due to the pi-pi stacking interactions of the coumarin groups. This AIEE effect of 1 is utilized to design probe for the detection of Hg2+ in a luminescence turn-on mode. The functionalization of the AIEE-active molecule with chelating group provides the potential binding sites for Hg2+. The selective coordination-induced aggregation bursts the emission. 1 has been successfully applied to detect Hg2+ in aqueous and living cells. (C) 2015 Elsevier B.V. All rights reserved.