New Cu(II), Co(II), Ni(II) complexes with aroyl-hydrazone based ligand. Synthesis, spectroscopic characterization and in vitro antibacterial evaluation.

A new aroyl-hydrazone, N-(2-pyridinecarbaldehyde)-N'-[4-(4-chloro-phenylsulfonyl) benzoyl]-hydrazone (L) and its Cu(II), Co(II) and Ni(II) complexes have been prepared. The structure of these compounds has been investigated by using elemental analysis, magnetic susceptibility, molar conductance, thermal and spectral (IR, UV, NMR, LC-MS, EPR) measurements. The semi-empirical method MM2, LC-ESI-MS, NMR and IR spectra indicate that the ligand behaves as mononegative bidentate/tridentate with NO/NON donor sequence in E isomeric form towards the metal ions. The magnetic and spectral data indicate a square-planar geometry for Ni2+ complex and an octahedral or pseudo-tetrahedral geometry for Co2+ and Cu2+ complexes. Bacterial activity of acyl-hydrazone (L) and its complexes were studied against gram-positive bacteria: Staphylococcus aureus, Bacillus subtilis and gram-negative bacteria: Pseudomonas aeruginosa, Escherichia coli by using minimum inhibitory concentrations (MICs) method.