Physicochemical and antimicrobial investigation on some selected arylhydrazone complexes

Some selected transition (Cu, Cr, Mn, Fe, Co and Ni) and non-transition (Zn and Pb) metal complexes of arylhydrazones, namely o-hydroxyacetophenone benzoylhydrazone (HBH) and o-mthoxybenzaldehyde benzoylhydrazone (MBH) have been isolated and characterized by a combination of elemental analysis, spectral (UV-Vis., IR, H NMR) and magnetic measurements. Only two divalent metals (Cu and Ni) yield stable complexes with MBH. The mode of bonding as well as the geometry of the solid complexes was identified. The results and discussion pointed out that HBH and MBH coordinate to the central metal ion in a bi and/or tridentate manner with forming a dimeric structures in case of Cu, Fe, Ni, Zn and Pb-HBH while a classic mononuclear structures in case of (Cu, Ni-MBH) and (Cr, Mn-HBH) complexes. The amount of solvent inside and outside the coordination sphere of solid samples was determined by the aide of thermal measurements. The prepared ligands and their metal complexes have been evaluated for their antimicrobial activity against Gram-positive and Gramnegative bacteria as well as for antifungal activity. The metal complexes were much more active than the original compound. In addition, the complex Ni-HBH showed the highest both antifungal and antibacterial activities against all microbial tested whilst the compound MBH revealed the lowest.