A benzimidazole functionalized NDI derivative for recyclable fluorescent detection of cyanide in water

Abstract

A fluorescent chemosensor (L2) has been designed and synthesized via a simple one step reaction through rationally combining benzimidazole and naphthalene diimide (NDI) moieties together. The structure of L2 has been confirmed by single crystal X-ray diffraction. The sensor L2 shows a highly selective and sensitive fluorescence response for CN⁻. Upon the addition of a CN⁻ water solution into the DMSO solution of sensor L2, the solution of L2 shows an instant fluorescence enhancement and other anions couldn't interfere in the CN⁻ detection process. The CN⁻ sensing process shows reversible properties by adding H⁺ into the sensor L2 solution treated by CN⁻. The detection limit of the sensor towards CN⁻ is 8.32 × 10⁻⁷ M, which could be distinguished by the naked eye in a UV lamp. The sensor L2 could serve as a practical and convenient recyclable test kit to detect CN⁻.