A highly stable, luminescent and layered zinc(II)-MOF: Iron(III)/copper(II) dual sensing and guest-assisted exfoliation

A highly stable and luminescent metal-organic framework (LMOF) with layered structure, namely, C₆H₄N₅OZn (1) has been successfully achieved and fully characterized by single crystal X-ray diffraction, powder X-ray diffractions, fluorescence titration and thermogravimetry. This blue-light emitting compound 1 exhibit outstanding stability and can detect Fe³⁺ and Cu²⁺ in water specifically, presenting potential application in the field of fluorescent probe technology. Fluorescence titration experiments indicate that the detection of Fe³⁺ ions by 1 is more significant than that of Cu²⁺ ions in terms of K_sv value. Furthermore, guest-assisted exfoliation of layered MOF 1 is efficiently carried out through ether O[sbnd]H hydrogen bond or π···π interactions between the layered host structure and intercalated guest molecules (4,4′-oxybisbenzoic acid and triphenylamine). Tyndal scattering was observed in the suspensions of obtained MOF nanosheets. This study shows that the compound 1 with unique metal ion sensing properties can be applied as a probe material in water pollution treatment field, but also opens up the opportunity for synthesizing luminescent MONs through the “bottom-up” guest intercalation methodology.