Colorimetric Fluorescence of a 2,4,5‐Triaryl Imidazole‐Based Sensor for the Selective Detection of Iron

Abstract

Two imidazole‐based color‐changing fluorescent probes 4‐(4,5‐bis(4‐chlorophenyl)‐1H‐imidazol‐2‐yl)‐N, N‐diphenylaniline (CIN) and 4‐(4,5‐di(furan‐2‐yl)‐1H‐imidazol‐2‐yl)‐N, N‐diphenylaniline (FIN) were synthesized and characterized. The new probes CIN and FIN exhibit excellent selectivity and sensitivity towards Fe3+ with relatively low detection limits (0.26 μM and 0.10 μM) and strong anti‐interference properties. Both the probes CIN and FIN complex 1 : 1 with Fe3+ ion, and the complexation constants were 1.165×105 M−1 (CIN) and 1.899×105 M−1 (FIN), respectively. Moreover, CIN and FIN could be recycled by EDTA and could effectively monitor Fe3+ ions at pH 4–10, which ensures the sensor‘s potential for detecting Fe3+ in actual aqueous solutions. The probes were further applied to the detection of Fe3+ in the actual reaction of Fe2+ oxidation, and the filter paper and the probe solution are combined to make an indicator to detect Fe3+ more conveniently and quickly.