A Novel Dual Channel Fluorescent Probe for Ca2+ and Zn2+ Based on a Coumarin Schiff Base

A novel coumarin Schiff base fluorescent probe ethyl 7‐hydroxycoumarin‐3‐carboxylate‐8‐formaldehyde benzoyl hydrazone (EBH) has been designed and synthesized which shows solvent dependent dual sensing, viz., recognition of Ca2+ in DMF‐H2O (9∶1, V/V) solution based on C = N isomerization, photoinduced electron transfer (PET) inhibition and chelation‐enhanced fluorescence (CHEF) mechanism as well as detection of Zn2+ in H2O‐CH3OH (9∶1, V/V) solution by excited‐state intramolecular proton transfer (ESIPT) and CHEF processes. The structure of the probe EBH has been confirmed by single‐crystal X‐ray diffraction analysis. Meanwhile, the probe was also used to image intracellular Zn2+ ions in MCF‐7 cells with a good performance.