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

A NbO-type Zn(II) metal-organic framework of {[Zn-2(HL)(H2O)(2)]center dot H2O}(n) (1) has been developed using a pentacarboxylate 2,5-bis(3', 5'-dicarboxylphenyl)-benzoic acid (H5L) ligand and characterized. The single-crystal X-ray diffraction studies indicate that 1 comprises free -COOH groups and Zn(II) centers bridged by four carboxylate groups to form a paddle wheel SBU which is further connected by L5- ligands to build a 3-D porous network with two types of cages. The chemically stable MOF 1 behaves as a highly selective and sensitive fluorescent chemosensor for the detection of Fe3+ ions, 2,4,6-trinitrophenol (TNP), which is known to be an extremely hazardous and strong explosive. Furthermore, the photocatalytic properties of 1 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 1 against organic dyes has been supported using density of states (DOS) calculations. [GRAPHICS]