The large-scale use of pesticides such as organophosphates pesticides (OPPs) and organochlorines pesticides (OCPs) has led to serious environmental problems worldwide, and their high toxicity could cause serious damage to...

Four novel lanthanide­(III)-based metal–organic frameworks (MOFs), formulated as [Ln3(HDDB)­(DDB)­(H2O)6]­·NMP·3H2O (Ln = Eu (1), Tb (2), Dy (3), Gd (4)), were successfully constructed with a rigid pentacarboxylate ligand 3,5-di­(2′,4′-dicarboxylphenyl) benzoic acid (H5DDB). Complexes 1–4 are isostructural and exhibit a new 3,4,4,6-connected network. 1–2 exhibit excellent fluorescence properties and good water stability. The emissions of the doped bimetallic Eu x Tb1–x -MOFs can be adjusted by varying the Eu­(III)/Tb­(III) ratios used in the reaction. Furthermore, 2 presents excellent sensitivity and selectivity to sense vitamin B6 (VB6) and the pesticide 2,6-dichloro-4-nitroaniline (DCN) as a multiresponsive luminescent sensor. Compound 2 is the first MOF-based luminescent sensor for detecting VB6 with a low detection limit (LOD) of 9.5 × 10–8 M (∼58.4 ppb) in phosphate buffer solution (pH = 6.86), which also displays a high-sensitivity sensing activity for VB6 in human serum. Moreover, 2 exhibits high-sensitivity sensing for the pesticide DCN with an LOD value of 1.4 × 10–7 M (∼86.1 ppb) in aqueous solution, and it also can be successfully used for detecting DCN in the extracts of carrots, grapes, and nectarines.

A zinc(ii)-based metal–organic framework exhibits fluorescence turn-on behaviour for Fe3+ and AA with high sensitivity and selectivity.