A Fluorescent Anionic MOF with Zn 4 (trz) 2 Chain for Highly Selective Visual Sensing of Contaminants: Cr(III) Ion and TNP.

Heavy-metal ions and nitroaromatic substances are highly toxic and harmful to human health and the ecological environment. It is an urgent issue to selectively detect and capture these toxic substances. By introducing the triazole ligand to the π-conjugated aromatic carboxylate system and borrowing the organic template open framework idea, a stable fluorescent framework [Me2 NH2 ]4 [Zn6 (qptc)3 (trz)4 ]·6H2 O (1) (H4 qptc = terphenyl-2,5,2'5'-tetracarboxylic acid, trz = 1,2,4-triazole) has been successfully synthesized, which features Zn4 (trz)2 chain-based 3D anionic structure with channels filled by [Me2 NH2 ]+ cations. It is worth noting that the material exhibits selective adsorption and recyclable detection of heavy-metal Cr3+ ion in aqueous solutions, which may be the synergy from the metal charge, bond ability of metal ions to carboxylate oxygen atom, and soft-hard acid-base properties. Furthermore, it can selectively sense of 2,4,6-trinitrophenol with a large quenching coefficient Ksv of 2.08 × 106 M-1 .