A Zn-MOF constructed from electron-rich π-conjugated ligands with an interpenetrated graphene-like net as an efficient nitroaromatic sensor

Abstract

A novel zinc-based luminescent metal–organic framework (Zn-MOF) has been successfully constructed based on a designed flexible and electron-rich N-involved linker (HL = 4-(bis(4-(pyridin-4-yl)phenyl)amino)benzoic acid). The framework of this Zn-MOF exhibits a 2-fold interpenetrated network which is composed of (3,3)-c sheets. The Zn-MOF has a strong solid state emission at 512 nm. The luminescence signal of the Zn-MOF can be quenched efficiently by trace amounts of electron-deficient nitroaromatics, especially 2,4,6-trinitrophenol (TNP). The quenching constant (K_sv) for TNP is 2.11 × 10⁴ M⁻¹, indicating that this framework can be employed as an excellent chemical sensor for identifying and quantifying TNP. This work highlights a strategy for designing a N-involved π-electron-rich enhanced ligand with nucleophilic properties for MOF-based materials as sensors. It also paves the way toward exploring other more efficient MOF materials as sensors for determining electron-deficient nitroaromatics.