Novel complexes of Cu(II), Ni(II), Co(II), Zn(II) and VO(II) have been prepared using a Schiff base derived from 1-phenyl-2,3-dimethyl-4-imino-benzylidene-pyrazol-5-one and dimethylglyoxime. The structural features of the chelates have been confirmed by microanalytical data, IR, UV-Vis., ¹H NMR and ESR spectral techniques. Electronic absorption and IR spectra of the complexes indicate an octahedral geometry around the central metal ion except VO(II) complex which shows square pyramidal geometry. The monomeric nature of the complexes is confirmed from their magnetic susceptibility. Low conductance data of the chelates support their non-electrolytic nature except vanadyl complex which shows electrolytic in nature due to the presence of sulphate ion outside the coordination sphere. The cyclic voltammogram of the copper and vanadyl complexes in MeCN at 300 K were well studied. The ESR spectra of copper and vanadyl complexes in DMSO solution at 300 and 77 K were recorded and their salient features are reported. The molecular orbital coefficients were calculated for the complexes. The antimicrobial activity of the ligand and its complexes has been extensively studied on microorganisms such as Staphylococcus aureus, Klebsiela pneumoniae, Bacillus subtilis, Escherichia coli and Salmonella typhi. Most of the complexes have higher activity than that of the free ligand.

Keywords: Schiff Base; 4-Aminoantipyrine; Dimethyl Glyoxime; Antimicrobial Activities;