Highly selective probe of a copper(II) complex based on a coumarin derivative for hydrogen sulfide detection

A fluorescent probe 1 containing copper(II) had been designed and synthesized based on a coumarin derivative. The molecular structure of probe 1 was characterized by 1H NMR, HRMS, IR, and elemental analysis. The interactions of 1 with biologically important anions and amino acid were determined by UV–Vis, fluorescence, and HRMS titration experiments. Results indicated that probe 1 showed the highest binding ability for HS− among studied anions (AcO−, H2PO4−, F−, Cl−, Br−, and I−) and cysteine in pure dimethyl sulfoxide (DMSO) and HEPES buffer solution. As we expected, the response of UV–Vis spectra in aqueous solution was stronger than that of pure DMSO solvent. In addition, the binding ability for HS− was not hindered by the existence of other anions. HRMS titration experiment showed that the interacted mechanism was that the copper(II) ion in 1 was captured by HS− and then free ligand released. Furthermore, the detection limit of probe 1 with HS− was carried out through UV–Vis titration showing 1 to be highly sensitive for HS−.