Synthesis, Characterization and Crystal Structures of N’-(2-hydroxy-4-methoxybenzylidene)-3-Trifluoromethylbenzohydrazide and its Nickel(II) and Iron(III) Complexes with Antibacterial Activity

A new aroylhydrazone compound N’-(2-hydroxy-4-methoxybenzylidene)-3-trifluoromethylbenzohydrazide (H2L) is synthesized and characterized by elemental analysis, IR, 1H and 13C NMR spectra. Reaction of H2L as ligand with nickel(II) acetate and iron(III) chloride, respectively in methanol affords complexes Ni2L2(CH3OH)4 1 and FeCl2(HL)(CH3OH) 2. Both complexes are characterized by elemental analysis and IR spectra. Structures of H2L∙CH3OH and the complexes are further confirmed by single crystal X-ray determination. The NiII and FeIII atoms in both complexes are in octahedral coordination. The dianionic enolate form of the aroylhydrazone ligand in the nickel(II) complex coordinates to NiII atoms through phenolate oxygen, imino nitrogen and enolate oxygen. The monoanionic keto form of the aroylhydrazone ligand in the iron(III) complex coordinates to FeIII atom through phenolate oxygen, imino nitrogen and carbonyl oxygen. Crystals of the compounds are stabilized by hydrogen bonds. Biological assay indicates that the compounds have effective antibacterial activity.