A simple symmetric N1, N2-bis 3-nitrobenzylidene fluorescent probe for Fe3+ ion: experimental and theoretical investigations

A symmetric small molecule fluorescent chemosensor L based on 3-nitrobenzaldehyde was synthesized by the reaction of ethylenediamine with 3-nitrobenzaldehyde in methanol and the product gained was utilized for the detection of Fe 3+ by fluorescence quenching “turn on‐off” process. The fluorescence spectral data results of the probe L specified that 9.54 × 10 4 M −1 as binding constant of L for Fe 3+ and the detection limits as 1.28 × 10 −6 M −1 . A possible C=N isomerization and a reverse PET mechanism is proposed for the probe L detection system for Fe 3+ ions constructed on the fluorescence studies and supported by the DFT calculation findings including the binding stoichiometry of the probe L with Fe 3+ ion as 1:1. To demonstrate its practical utility, the sensing system was investigated for the real water sample analysis and determination of iron in iron tablet. Graphical abstract