Synthesis and characterization of MOFs constructed from 5-(benzimidazole-1-yl)isophthalic acid and highly selective fluorescence detection of Fe(iii) and Cr(vi) in water

Abstract

In this work, four novel metal–organic frameworks [Cd(bipa)]_n (1), {[Zn₂(bipa)₂]·2C₂H₅OH}_n (2), {[Co(bipa)]·C₂H₅OH}_n (3), {[Ni(bipa)₂]·2DMA}_n (4), (H₂bipa = 5-(benzimidazole-1-yl)isophthalic acid) were successfully synthesized under solvothermal conditions. Complexes 1–4 were characterized by powder X-ray diffraction, elemental analysis, infrared spectroscopy and thermogravimetric analysis. Interestingly, the coordination patterns and 3D network structures of complexes 1–3 are very similar, while complex 4 is relatively unique. Complexes 1–2 exhibit potential fluorescent properties. Complex 1 can selectively and sensitively detect trace Fe(III) and Cr(VI) in water by fluorescence quenching detection, and the quenching mechanism is further discussed.