A highly selective fluorescent chemosensor for cyanide anions based on a chalcone derivative in the presence of iron(III) ions, and its capacity for living cell imaging in mixed aqueous systems

A chalcone, 4-dimethylamino 4-fluorochalcone (1) with donor-acceptor structure characteristics is found to exhibit a distinct green fluorescence and good stability in CH₃CN/water (v/v = 1: 9) buffer solution (Tris-HCl, pH = 7.4), and the in situ formed 1-Fe³⁺ complex upon addition of Fe³⁺ serves as a highly selective cyanide anion probe via a turn-on fluorescence mechanism. Furthermore, the fluorescence imaging experiments of 1-Fe³⁺ in the presence of CN^- in human glioma living cells (U251) demonstrate its potential for practical applications in biological and environmental systems.