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-Cu 2+ with Cu 2+ to realize the "turn-off" detection of Cu 2+ with high specificity and sensitivity (3.7 × 10 –7  mol/L). Meanwhile, the complex L-Cu 2+ had a specific fluorescence-enhanced response to HPO 4 2− with a detection limits down to 5.6 × 10 –7  mol/L and was resistant to the effects of many common anions (NO 2 − , N 3 − , CO 3 2− , SO 3 2− , HPO 4 2− , I − , Br − , F − , HCO 3 − , SO 4 2− , NO 3 − , Cl − , CH 3 COO − , Cr 2 O 7 2− , S 2 O 3 2− , P 2 O 7 4− ). Detection mechanism could be HPO 4 2− captured Cu 2+ of the complex and released the free ligand L. At last, the complex L-Cu 2+ was successfully applied to the determination of HPO 4 2− in different environmental water samples, and the spiked recoveries ranged from 98.05% to 108.18% and the relative standard deviations of 0.75% ~ 2.9%, which had good application prospects. Graphical A new coumarin acyl hydrazone fluorescent probe L was designed and synthesized, which could specifically recognize Cu2+ and HPO42- in a relay manner. In addition, the probe had good prospects for practical applications.