A Water-Stable Metal–Organic Framework for Highly Sensitive and Selective Sensing of Fe³⁺ Ion

A new metal–organic framework [Zn 5 (hfipbb) 4 (trz) 2 (H 2 O) 2 ] ( NNU-1 ) [H 2 hfipbb = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid), Htrz = 1 H -1,2,3-triazole] was assembled by hydrothermal synthesis. Single-crystal X-ray diffraction analysis reveals that NNU-1 displays a twofold interpenetrating three-dimensional (3D) framework with a {4 24 ·6 4 }- bcu topology. Interestingly, the 3D framework contains a two-dimensional (2D) layered structure that consists of alternating left- and right-handed double helical chains. On the basis of the hydrophobic −CF 3 groups from H 2 hfipbb ligand, NNU-1 possesses excellent stability in water. It is worth noting that NNU-1 not only shows a highly selective fluorescence quenching effect to Fe 3+ ion in aqueous solution but also resists the interference of other metals including Fe 2+ ion. Accordingly, NNU-1 probably functions as a potential promising fluorescence sensor for detecting Fe 3+ ion with high sensitivity and selectivity.