Synthesis, spectral studies and antibacterial activity of Cu(II), Co(II) and Ni(II) complexes of 1-(2-hydroxyphenyl)-3-phenyl-2-propen-1-one, N-2-[3,5-dimethyl-1H-pyrazol-1-yl)methyl]hydrazone

A new series of Cu(II), Co(II) and Ni(II) complexes with the 1-(2-hydroxyphenyl)-3-phenyl-2-propen-1-one, N-2-[(3,5-dimethyl-1H-pyrazol-1-yl)methyl]hydrazone ligand, C21H22N4O (LH), were synthesized by the reaction of 1-(2-hydroxyphenyl)-3-phenyl-2-propen-1-one, hydrazone with (3,5-dimethyl-1H-pyrazol-1-yl)methanol and characterized. The nature of the bonding and geometry of I the complexes were deduced from elemental analysis, IR, electronic and H-1-NMR spectroscopy, and magnetic susceptibility and conductivity measurements. The studies indicated square-planar, tetrahedral and octahedral geometry for the copper(II), cobalt(II) and nickel(II) complexes, respectively. The ESR spectra of the copper(II) complex in acetonitrile at 300 and 77 K were recorded and their salient features are reported. The electrochemical behavior of the copper (II) complex was studied by cyclic voltammetry. The antimicrobial activity of the ligand and its metal complexes were studied against the following strains of microorganism: Staphylococcus aureus, Salmonella enterica typhi, Escherichia coli and Bacillus subtilis by the well diffusion method. Metal complexes showed enhanced antimicrobial activity compared with that of the free ligand.