3-Hydroxy-N'-(2-hydroxy-4-methoxybenzylidene)benzohydrazide and its isostructural cobalt(II) and nickel(II) complexes: Synthesis, X-ray crystal structures and antibacterial activity.

A new hydrazone compound 3-hydroxy-N'-(2-hydroxy-4-methoxybenzylidene)benzohydrazide (HL) and its isostructural cobalt(II) and nickel(II) complexes [M2Cl2L2(EtOH)2] (M = Co for 1, Ni for 2) were synthesized and characterized by physico-chemical methods such as elemental analysis, infrared and electronic spectroscopy. The free hydrazone HL was also characterized by 1H and 13C NMR spectroscopy. Structures of HL and the two complexes were further confirmed by single crystal X-ray determination. The hydrazone ligand in the complexes coordinates to the metal atoms through phenolate oxygen, imino nitrogen and carbonyl oxygen atoms. The metal atoms in the complexes are in octahedral coordination. The hydrazone and both complexes were assayed for antibacterial activities on the bacterial strains Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and on the fungal strains Candida albicans and Aspergillus niger, and gave interesting results.