Fluorescence ‘Turn‐on’ Receptor 2‐((E)‐(6‐(Diethylamino)‐2‐methylpyridin‐3‐ylimino) Methyl) Phenol for Nanomolar Fe (III) Detection in Lung Cancer Cells

A newly designed receptor 2‐((E)‐(6‐(diethylamino)‐2‐methylpyridin‐3‐ylimino) methyl)phenol ( DMP ) behaves as a highly selective ratiometric fluorescent receptor for Fe 3+ in acetonitrile solvent. Probe DMP showed a detectable color change from yellow to light pink with a blue‐shift with addition of Fe 3+ in the absorption spectra. A decrease in fluorescence at 424 nm and a red‐shift to 457 nm with a substantial fluorescence enhancement in the presence of Fe 3+ indicated the formation of DMP.Fe 3+ complex. The binding constant ( K a ) for a 2:1 stoichiometry was found to be 3.33 × 10 4 M −1 with a detection limit of 7.739 nM. Theoretical calculations were studied to establish the configurations of DMP.Fe 3+ complex, which supported the observed fluorescence turn‐on phenomenon. DMP was found to be efficient in detecting Fe 3+ in vitro and has high applicability in lung cancer (A549) cell imaging.