Facile synthesis, characterization, and antibacterial activities of CuO, NiO, and Co2O3 metal oxide nanoparticles using polysalicylaldehyde-metal Schiff base complexes as a precursor

In this study, NiO, CuO, and Co2O3 NPs with noteworthy antibacterial activity have been efficiently synthesized by a thermal decomposition of polysalicylaldehyde Schiff base-M(II) complexes (M = Cu, Ni, and Co), as the promising precursors. Polysalicylaldehyde (PSA) Schiff base ligand has been synthesized via the condensation reaction of the 2-aminophenol with polysalicylaldehyde followed by metal coordination to Cu(II), Ni(II), and Co(II) ions. The nanoparticles were obtained in high uniformity and homogeneous morphology with high purity and crystallinity by the thermal decomposition of the corresponding PSA Schiff base complexes. A very uniform and narrow size distribution of nanoparticles with spherical morphology and an average diameter between 20 and 22 nm was obtained for all three nanoparticles. The results of characterization analyses showed high purity and high crystallinity percentage of the prepared nanoparticles. The antibacterial activity of all three nanoparticles on Escherichia coli, Bacillus cereus, and Staphylococcus aureus was studied by well diffusion method as well as MIC analysis. All three nanoparticles showed a significant antibacterial effect compared to the initial complex. A promising protocol has been developed for the uniform-sized metal oxide nanoparticles (CuO, NiO, and Co2O3 NPs) with high antibacterial activity using thermal decomposition of polysalicylaldehyde M-Schiff base (Co(II), Ni(II), Cu(II)) complexes.