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

Graphical Two imidazole-based color-changing fluorescent probes 4-(4,5-bis(4-chlorophenyl)-1 H -imidazol-2-yl)- N , N -diphenylaniline (CIN) and 4-(4,5-di(furan-2-yl)-1 H -imidazol-2-yl)- N , N -diphenylaniline (FIN) were synthesized and characterized. The new probes CIN and FIN exhibit excellent selectivity and sensitivity towards Fe 3+ with relatively low detection limits and strong anti-interference properties. Both the probes CIN and FIN complexed 1 : 1 with Fe 3+ ion. Two imidazole-based color-changing fluorescent probes 4-(4,5-bis(4-chlorophenyl)-1 H -imidazol-2-yl)- N , N -diphenylaniline (CIN) and 4-(4,5-di(furan-2-yl)-1 H -imidazol-2-yl)- N , N -diphenylaniline (FIN) were synthesized and characterized. The new probes CIN and FIN exhibit excellent selectivity and sensitivity towards Fe 3+ 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 Fe 3+ ion, and the complexation constants were 1.165×10 5 M −1 (CIN) and 1.899×10 5 M −1 (FIN), respectively. Moreover, CIN and FIN could be recycled by EDTA and could effectively monitor Fe 3+ ions at pH 4–10, which ensures the sensor‘s potential for detecting Fe 3+ in actual aqueous solutions. The probes were further applied to the detection of Fe 3+ in the actual reaction of Fe 2+ oxidation, and the filter paper and the probe solution are combined to make an indicator to detect Fe 3+ more conveniently and quickly.