Photocatalytic properties of two new isostructural cobalt(II) and nickel(II) complexes having terphenyl-3,3″,4,4″-teteacarboxylic acid

Abstract

The effective and rapid removal of organic pollutants from wastewater is very important for the safety of aquatic environment. Photocatalytic degradation is a feasible strategy that can safely eliminate the organic pollutants from the wastewater discharge. Amongst varied class of photocatalysts, the coordination polymers (CPs) are important class of material that can be used to remove and degrade the organic dyes from wastewater. Herein, two isostructural coordination polymers, having compositions [Ni2(H2L)2(phen)4·H4L·6H2O)] (1) and [Co2(H2L)2(bipy)4·H4L·6H2O)] (2) (H4L = terphenyl-3,3″,4,4″-teteacarboxylic acid, phen = 1,10-phenanthroline and bipy = 2,2′-bipyridine) have been synthesized and characterized. Both of the isostructural compounds display dinculear architecture, where metal centers are coordinated to two carboxylic groups, which further forms a 2D supramolecular layer via hydrogen bonds formed between the water molecules and uncoordinated carboxylate groups. Both the compounds have been used as photocatalysts to catalyze the photodegradation of methylene blue (MB) and methylene violet (MV) under UV irradiation. The Ni(II)-based photocatalyst 1 exhibited the good photocatalytic performance in comparison to that of 2. The observed differences in the photocatalytic properties of both the CPs have been addressed using Hirshfeld surface analyses.