Novel acylhydrazone-based supramolecular gel for super-sensitive detection of Fe3+ and alternant detection of CN− in aqueous medium

Abstract

Specific detection of ultratrace levels of ions in aqueous solution without costly equipment and advanced technical is a hot research topic for environmental monitoring. A new gelator molecular, (E)-N’-(4-bromobenzylidene)-4-methoxybenzohydrazide (BM), has been simply synthesized via a 1-step pathway. The obtained molecular BM could self-assembled in N,N-Dimethylformamide (DMF) and formed a stable organogel (OBM) via multi-self-assembly driving forces. Interestingly, OBM had a fluorescence ‘‘turn-off’’ detection signal for Fe3+ and formed a complex OBM-Fe3+. When CN− ions are added to the Fe3+ coordinated metal-organic gel, the fluorescence intensity was increased to the original strength of the supramolecular gel OBM again. The sensing mechanism of CN− was determined through the competitive coordination action of supramolecular gel OBM, Fe3+ cations and CN− anions. Simultaneously, the organogel sensor OBM could also serve as ion responsive films for the detection of Fe3+ and CN−.