Antimicrobial activity of some pyrazolidin-3-one Schiff base derivatives and their complexes with selected metal ions

In spite of the fact that the structural similarity of pyrazolidin-3-one based compounds with the triazole, the antimicrobial activity of pyrazolidin-3-one compounds, have been investigated by many research groups to achieve potent antimicrobial agents. As result of the emerged drug resistance for many antimicrobial agents, we aimed in the current study to develop new potent and safe antimicrobial agents. In this study, a series of novel antimicrobial pyrazolidin-3-one based compounds and their transition metal complexes with Fe (II), Mn (II), Co(II), Ni(II), Zn(II), Cd(II), Cu(II), Pt(II) and Mo(II) ions were synthesized in good yields using microwave irradiation. All synthesized compound (free ligands and their metal complexes) were fully characterized by several spectroscopic techniques such as molar conductance, infrared, UV/Visible electronic, 1H NMR and 13C NMR spectra. In addition, the elemental analyses and conductivity investigations were done and combined with other spectroscopic data to determine the ligand: metal [M: L or L:M] ratio. The free unattached ligands and their complexes were screened for their in vitro antimicrobial activity against Staphylococcus aureus (ATCC29213) Escherichia coli (ATCC-25922), and Candida albicans (ATCC-10231). The achieved results indicated that some complexes are more potent than their free ligands and metal ions (Fe (II), Pt (II), Co(II), and Ni(II)), and some of the complexes are more potent than the standard antifungal amphoteracine-B. In conclusion, the biological activity results indicated the enhancement of the antimicrobial activity of some imine derivatives of pyrazolidin-3-one will open the field for scientists to develop more effective and safe drugs.