A highly selective turn-on sensor for paramagnetic Fe3+ ions based on (E)-N'-((2-aminophenyl)(phenyl)methylene)thiophene-2-carbohydrazide is successfully synthesized. The sensor BPTH is significantly selective and sensitive towards Fe3+ ions over other interfering metal ions especially Cu2+ and Co2+ ions with a lowest limit of recognition 1.48 × 10-7 M. The turn-on sensing mechanism involves enhanced charge transfer. Fe3+ ion forms strong binding with the ligand with a Ka value about 8.23 × 104 M-1 and a 1:1 stoichiometric ratio is confirmed by Job's plot experiment. With Fe3+ ion, the yellow ligand BPTH change to a green fluorescent and reversible with 1 equivalent of EDTA. Practical application of sensor is demonstrated in real sample analysis.
Keywords: Charge transfer; Iminobenzophenone; Iron (III); Paramagnetic; Thiophen hydrazide; Turn-on.
© 2023. The Author(s), under exclusive licence to European Photochemistry Association, European Society for Photobiology.