Synthesis of Coumarinylhydrazone Fluorescent Probe and its Relay Recognition of Cu2+ and HPO42−

A novel coumarinylhydrazone fluorescent probe L was designed and synthesized from 4-(diethylamino)salicylaldehyde, its structure was characterized by NMR, IR. Fluorescence emission spectra showed that in ethanol solution, probe L could form a 1:1 complex L-Cu2+ with Cu2+ to realize the "turn-off" detection of Cu2+ with high specificity and sensitivity (3.7 × 10–7 mol/L). Meanwhile, the complex L-Cu2+ had a specific fluorescence-enhanced response to HPO42− with a detection limits down to 5.6 × 10–7 mol/L and was resistant to the effects of many common anions (NO2−, N3−, CO32−, SO32−, HPO42−, I−, Br−, F−, HCO3−, SO42−, NO3−, Cl−, CH3COO−, Cr2O72−, S2O32−, P2O74−). Detection mechanism could be HPO42− captured Cu2+ of the complex and released the free ligand L. At last, the complex L-Cu2+ was successfully applied to the determination of HPO42− in different environmental water samples, and the spiked recoveries ranged from 98.05