This is the first comprehensive review of the biological activity of hydrazone-transition metal complexes. Hydrazone complexes gained much attention because of their antifugial, antibacterial anticonvulsant, and analgesic, antiinflammatory, antimalarial, antimicrobial, antituberculosis, anticancer, and antiviral activities. Additionally, some of the hydrazone complexes were used in treatment of iron overload diseases. One application, which reflects the importance of hydrazone complexes, is their use in detection and determination of metals and some organic constituents in pharmaceutical formulations. This review will provide an overview of the biological, analytical and catalytic applications of this category of complexes.

The coordination chemistry of N′-((1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)methylene)-2-hydroxybenzohydrazide with copper(II), nickel(II), cobalt(II), manganese(II), zinc(II), palladium(II), iron(III), ruthenium(III), uranyl(VI), and titanium(IV) has been studied. The ligand and its complexes was characterized by elemental and thermal analyses, magnetic moments and conductivity measurements as well as spectroscopic techniques such as infrared, mass spectra, nuclear magnetic resonance, electron spin resonance and electronic absorption spectra. The spectral data showed that the ligand is monobasic tridentate coordinated via the enolic carbonyl oxygen of the hydrazide moiety, azomethine nitrogen and pyrazolone oxygen atoms.