An excellent water-stable 3D Zn-MOF with 8-fold interpenetrated diamondoid topology showing “turn-on/turn-off” luminescent detection of Al3+ and SNT in aqueous media

Abstract

The effective detection of Al³⁺ and antibiotics pollutants is crucial for environmental protection and human health due to their high toxicity and nondegradability, but it is still currently challenging. In this work, a methyl-decorated acylamide-containing dicarboxylate ligand H₂L was elaborately designed and successfully synthesized, which was further employed to react with Zn(II) ions and dpe ligands to construct a new luminescent Zn-MOF, namely {[Zn(L)(dpe)]·DMF·3H₂O}_n (1). X-ray crystallography reveals that MOF 1 is a 3D 8-fold [4 + 4] interpenetrated diamondoid framework with isolated DMF and water molecules in the pores, in which the uncoordinated acylamide groups are found and facilitate the Zn-MOF to recognize analyte molecules. The activated solvent-free MOF sample (denoted as 1a) exhibits excellent water stability and good luminescent performance. The luminescence sensing experiments show that 1a could behave as a bi-responsive chemical sensor for “turn-on” and “turn-off” luminescent detection of Al³⁺ and SNT in aqueous media, respectively. The sensing mechanisms have also been discussed. Furthermore, MOF 1a was successfully applied to the effective determination of Al³⁺ and SNT in real water samples. This represents, to our knowledge, the first example of a MOF material for “turn-on” and “turn-off” luminescent detection of Al³⁺ and SNT in water, which will promote the practical application of water-stable luminescent MOF sensors in monitoring metal ions and antibiotics pollutants in the environmental water matrices.