Synthesis of Metal (II) Complexes of Co, Cu and Ni with Organic Ligand (Maleic Acid) and Their Antioxidant Activities

by Emeka Walter Ndubuisi, Hassan B. Yesufu, Lawrence Ocheme Akor, Wadai Smith

Published: October 13, 2025 • DOI: 10.51244/IJRSI.2025.120800331

Abstract

Complexes of Co, Ni and Cu with maleic acid as ligand were synthesized using reported procedure and characterized using UV spectrometry. The purity of the complexes was monitored and analyzed using solubility, melting point test and the complexes were evaluated for anti-oxidant activities against 1,1-diphenyl-2-picrylhydraxyl(DPPH) free radicals. All the complexes are of good yield, they are of different colors, partially soluble in organic solvent and soluble in DMF. The result was analyzed and presented as mean± SEM. The complex of Co, Ni and Cu at the concentration of 100ug/ml, 50ug/ml, 25ug/ml and 12.5ug/ml respectively shows less scavenging activity compared to the standard (vitamin C) at all concentration. The EC50 result shows that all the complexes have less activity compared to the standard (Vit C.) but still showing notable antioxidant capacity. On the bases of the above studies, an octahedral has been proposed for the complexes.