A new coumarin-based fluorescence turn-on chemodosimeter for Cu2+ in water

A highly selective and sensitive coumarin-based chemodosimeter 1 for Cu2+ in water is reported in this work. 1 was designed and facilely synthesized by a one-step reaction with coumarin as a fluorophore and 2-picolinic acid as the binding moiety, which showed very week fluorescence in buffer solution, and its fluorescence was considerably enhanced by the addition of Cu2+ at room temperature in 5 min. Mechanism study suggested that Cu2+ promoted the hydrolysis of 1 via the catalytic sensing cycle, generating a highly fluorescent product 7-hydroxycoumarin with fluorescence signal greatly amplified. The probe exhibited remarkably selective fluorescence enhancement to Cu2+ over other metal ions at 454 nm, with a detection limit of 35 nM Cu2+. Under optimal condition, 1 was successfully used for the determination of Cu2+ in fetal equine serum and two water samples. (C) 2011 Elsevier B.V. All rights reserved.