Highly selective fluorescent and colorimetric sensor for Hg2+ based on triazole-linked NBD

7-Nitrobenzo-2-oxa-1,3-diazole (NBD) derived compound 1 bearing triazole binding site was used as a selective fluorescent and colorimetric sensor for Hg2+ in aqueous solution. Among the metal ions examined, only Hg(2+)caused significant fluorescence quenching in EtOH/HEPES (v/v = 9:1) at pH 7.4, along with a remarkable red shift in both absorption and fluorescence spectra which then facilitated naked-eye detection. H-1 NMR titration and control experiments by using more rigid triazolyl NBD derivative 2 were carried out to illustrate the complexation mode and the importance of cooperation of amino acid moiety and triazole ring in improving the binding ability of 1 to Hg2+. (C) 2011 Elsevier Ltd. All rights reserved.