A highly sensitive and selective chemosensor for Pb(2+) based on quinoline–coumarin

In this study, a highly sensitive and selective fluorescent chemosensor, ethyl(E)-2-((2-((2-(7-(diethylamino)-2-oxo-2H-chromene-3-carbonyl)hydrazono)methyl)quinolin-8-yl)oxy)acetate (1), was synthesized and characterized by (1)H NMR, (13)C NMR and ESI-MS. Sensor 1 showed an “on–off” fluorescence response to Pb(2+) with a 1 : 1 binding stoichiometry in CH(3)CN/HEPES buffer medium (9 : 1 v/v). The detection limit of sensor 1 to Pb(2+) was determined to be 0.5 μM, and the stable pH range for Pb(2+) detection was from 4 to 8.