A Study on the Role of Dicarboxylic Acid Conjugated Copper(II) Complexes in the Reduction of p-Nitrophenol Under Mild Condition in Water Medium

Abstract

The present work reports the synthesis of Schiff base Cu(II) complexes 1–3 condensed with significant dicarboxylic acids as co-ligands. They have been synthesized and characterized by various spectral and analytical methods like microanalytical data, magnetic susceptibility values, molar conductivity measurements, UV-vis, IR, ¹H NMR, ¹³C NMR and EPR techniques. In addition to that XRD, morphological studies were also carried out. The complexes were found to reveal excellent catalytic activity. In this work, p-nitrophenol (p-NP) was reduced to p-aminophenol (p-AP) where novel dicarboxylic acid conjugated Cu(II) complexes were acting as catalysts. The demand to reduce the toxic p-NP, found in water bodies in a soluble and stable form has prompted us to undertake the work and carry it out effectively. These classified environmental hazards and their solubility posed a major problem in employing traditional water purification methods for the removal of p-NP from contaminated waste waters. The limited reports available on the metal complex catalytic reduction of p-NP encouraged us to carry out the same using the complexes synthesized by us. The efficiency of the catalytic reduction carried out in water medium has been evaluated towards the reduction of p-NP and the complete reduction was achieved within 70 min. The outcome of various physicochemical parameters and stability of the catalyst was also investigated. Fascinatingly, the catalyst was stable up to its 5th cycle and its efficiency was about 70%. Interestingly, the process is environmentally benign, universal, efficient, safe and operationally simple.