Selective Chemosensor of Fe3+ Based on Fluorescence Quenching by 2,2′-Bisbenzimidazole Derivative in Aqueous Media

2,2-Bisbenzimidazole derivative (L) was designed as a fluorescent chemosensor for Fe3+. This structurally simple chemosensor displays significant fluorescence quenching with increasing concentrations of Fe3+. L exhibited high selectivity and antidisturbance for Fe3+ among environmentally relevant metal ions in aqueous media. The method of Job's plot indicated the formation of 1:2 complex between L and Fe3+, and the possible binding mode of the system was also proposed. In addition, further study demonstrates the detection limit on fluorescence response of the sensor to Fe3+ is down to 107 mol center dot L1 range. The binding mode was investigated by fluorescence spectra, ESI-MS, IR data, 1H NMR, 13C NMR and crystal data.