A Coumarin-Based Fluorescence Probe for Selective Recognition of Cu2+ Ions and Live Cell Imaging

A new fluorescence probe L was rationally designed and synthesized for the recognition of Cu2+ ions by the combination of coumarin hydrazide and 2-acetylpyrazine. The photochemical properties and selectivity of L for Cu2+ ions in a CH3CN/HEPES (3 : 2, v/v) buffer were investigated by UV-vis absorption and fluorescence emission spectra. A highly selective and sensitive response of L for Cu2+ ions over other competing metal ions was observed with limit of detection in 3 μM. The coordination stoichiometry of L to Cu2+ ions was determined to be 1 : 1 by the UV-vis absorption spectrum, the fluorescence titrations, and density functional theory (DFT) calculations. Moreover, L was applied successfully for recognition of intracellular Cu2+ ions in living cells.