A porous zinc(II) metal–organic framework exhibiting high sensing ability for ferric and nitroaromatics as well as photocatalytic degradation activities against organic dyes

<p>A NbO-type Zn(II) metal–organic framework of {[Zn<sub>2</sub>(HL)(H<sub>2</sub>O)<sub>2</sub>]∙H<sub>2</sub>O}<sub>n</sub> (<b>1</b>) has been developed using a pentacarboxylate 2,5-bis(3′,5′-dicarboxylphenyl)-benzoic acid (H<sub>5</sub>L) ligand and characterized. The single-crystal X-ray diffraction studies indicate that <b>1</b> comprises free –COOH groups and Zn(II) centers bridged by four carboxylate groups to form a paddle wheel SBU which is further connected by L<sup>5−</sup> ligands to build a 3-D porous network with two types of cages. The chemically stable MOF <b>1</b> behaves as a highly selective and sensitive fluorescent chemosensor for the detection of Fe<sup>3+</sup> ions, 2,4,6-trinitrophenol (TNP), which is known to be an extremely hazardous and strong explosive. Furthermore, the photocatalytic properties of <b>1</b> for degradation of methyl violet (MV) and Rhodamine B (RhB) have been explored. The possible emission quenching mechanism in the presence of nitro-aromatics (NACs) has been addressed by theoretical calculations and photocatalytic activity of <b>1</b> against organic dyes has been supported using density of states (DOS) calculations.</p>