Novel probes based on coumarin-bisdithiocarbamate system for selective recognition of Ag(I) in aqueous solution

Two novel fluorescent probes (C1, C2), comprising a coumarin moiety as fluorophore and a pair of dithiocarbamates as recognition sites, were designed and synthesized as fluorescent probes for Ag+. The probes exhibited high selectivity for Ag+ with fluorescence enhancement (FE) in CH3CN/4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) (1:9, v/v, pH 7.38); the selectivity was not affected by other metal ions. The binding ratio of C2–Ag+ complex was determined to be 1:1 according to the Job plot and mass spectroscopy (MS) data. The association constant K a of Ag+ with C2 was 1.6 × 104 M−1. These probes could be applied for monitoring of Ag+ in aqueous solution in the pH range of 5.0–8.0, with calculated detection limit of 0.27 μM.