Synthesis, characterization and antioxidant study of Cu(II) and Ni(II) hydroxamic acid complexes / Syed Mohd Naqib Syed Zainal Abidin

The complexes of copper-benzohydroxamic acid (CuBHA) and nickel-benzohydroxamic acid
(NiBHA) were successfully synthesized using benzohydroxamic acid ligand and copper
sulfate pentahydrate (CuSO4.5H2O) and nickel chloride hexahydrate (NiCl2.6H2O) metal
salts. The metal salts and ligand were mixed at a raised temperature and pH adjustment was
made to obtain a precipitate. The structures of the complexes were determined by elemental
analysis, fourier-transform infrared (FTIR) and magnetic susceptibility. Unfortunately, both
complexes have solubility problems in dimethylsulfoxide (DMSO), chloroform, water,
methanol and acetone which have restricted them for nuclear magnetic resonance (NMR)
characterization. In addition, it was found that both complexes exhibit paramagnetic behavior
when magnetic susceptibility characterization was performed. The complexes have been
investigated for their reducing power capacity, which will indicate their potential of
exhibiting antioxidant property using the FRAP method. From the results obtained, it showed
that both Cu(BHA)2 and Ni(BHA)2 are very least likely to have or posses no potential to be
antioxidants