Highly Specific Probe for Ferric Ions in Aqueous Solution Based on 5, 6-Dicarboxy-3H-benzoimidazol-1-ium Nitrate†

The organic compound, 5, 6-dicarboxy-3H-benzoimidazol-1-ium nitrate (Hdcbii·NO3) (1), was synthesized by the reaction of 1H-benzoimidazole-5, 6-dicarboxylate (Hbidc) with nitric acid under hydrothermal conditions. The crystal structure of the compound shows abundant hydrogen bonds and π···π stacking interactions revealed by X-ray single crystal diffraction and FT-IR spectroscopy. This compound has high selectivity for ferric (Fe3+) ions in aqueous solution and shows strong potential for application as a fluorescent probe for ferric ions.