A New Tetrasubstituted Imidazole Based Difunctional Probe for UV-spectrophotometric and Fluorometric Detecting of Fe3+ Ion in Aqueous Solution

Two new compounds, 4-(2-bromophenyl-4,5-diphenyl-imidazol-1-yl)aniline(probe 1) and 4-[2,4,5-tris(4-bromophenyl)-1H-imidazol-1-yl]aniline(probe 2), were synthesized via a soft and high-efficiency one-pot microwave-assisted method under solvent-free conditions. Their sensing to different metal ions was detected by UV spectrophotometry and fluorescence spectrometry. Probe 2 revealed highly selective and sensitive UV and fluorescence response to Fe³⁺ ion. Upon the addition of Fe³⁺ ion, probe 2 showed obvious color change of the solution, conspicuous absorbance enhancement and relatively quick fluorescence quenching. The detection limit for Fe³⁺ ion was respectively calculated to be 0.72 μmol/L(fluorescent detection) and 0.48 μmol/L(UV-spectrum detection). Also, probe 2 was bound by Fe³⁺ ion to form a 1:1 complex. Moreover, preliminary application of probe 2 for detecting Fe³⁺ ion in aqueous solution was attempted, and satisfying results were obtained.