A highly stable 8-hydroxyquinolinate-based metal–organic framework as a selective fluorescence sensor for Fe3+, Cr2O72− and nitroaromatic explosives

Abstract

An 8-hydroxyquinolinate-based metal–organic framework [Zn(L)]·2MeOH·H₂O (1) was synthesized for the first time by treating a novel 8-hydroxyquinolinate ligand H₂L involving two carboxylate groups with zinc salt. Based on single-crystal X-ray analysis, the Zn-MOF exhibits a porous framework assembled from interlinked nanotubes that are constructed from three 4₃ helices. Complex 1 possesses excellent stability in both water and common organic solvents, which is conducive to its utility as a chemical sensor. The fluorescent sensing studies indicated that 1 can detect Fe³⁺ in aqueous solution with high sensitivity and selectivity even in the presence of other interfering metal cations. The recyclability and possible mechanism of 1 in the Fe³⁺ sensing process have been demonstrated. Additionally, fluorescent 1 is capable of sensing Cr₂O₇²⁻ in aqueous solution and nitroaromatic explosives in DMF. High selectivity and sensitivity were observed by fluorescence quenching effects. The above observations suggested that 1 can be considered as a potential fluorescent sensor for detecting Fe³⁺, Cr₂O₇²⁻ and nitroaromatic explosives.