An EDTA promoted coordination induced disaggregation for specific Hg2+ detection

In this work, a novel fluorescent sensing strategy was developed for the detection of Hg2+ with excellent sensitivity and selectivity using a metal-induced disaggregation of aggregated squaraine molecules with the help of ethylenediaminetetreaacetic acid (EDTA). This EDTA promoted probe exhibited a specific turn on fluorescent response to Hg2+ with a detection limit of 7.6 x 10(-9) M (3 sigma/k). Owning to the high coordinating ability of EDTA and dithiocarbamate tethered squaraine dye toward Hg2+, the disaggregation process could be improved by EDTA via the formation of squaraine-Hg2+-EDTA trinary complex, resulting in a greater fluorescent release, and this novel phenomenon has been confirmed by light scattering experiments, H-1 NMR, IR and MS. (C) 2014 Elsevier Ltd. All rights reserved.