title: Synthesis, characterization, biological activity and equilibrium studies of metal(II) ion complexes with tridentate hydrazone ligand derived from hydralazine.
abstract: In the present study, a new hydrazone ligand (2-((2-phthalazin-1-yl)hydrazono)methyl)phenol) prepared by condensation of hydralazine (1-Hydralazinophthalazine) with salicylaldehyde (SAH). The synthesized SAH-hydrazone and its metal complexes have been characterized by elemental analyses, IR, (1)H NMR, solid reflectance, magnetic moment, molar conductance, mass spectra, UV-vis and thermal analysis (TGA). The analytical data of the complexes show the formation of 1:1 [M:L] ratio, where M represents Ni(II), Co(II) and Cu(II) ions, while L represents the deprotonated hydrazone ligand. IR spectra show that SAH is coordinated to the metal ions in a tridentate manner through phthalazine-N, azomethine-N and phenolic-oxygen groups. The ligand and their metal chelates have been screened for their antimicrobial activities using the disc diffusion method against the selected bacteria and fungi. Proton-ligand association constants of (SAH) and the stepwise stability constants of its metal complexes are determined potentiometrically in 0.1 M NaNO(3) at different temperatures and the corresponding thermodynamic parameters were derived and discussed. The order of -ΔG° and -ΔH° were found to obey Mn(2+)<Co(2+)<Ni(2+)<Cu(2+), in accordance with the Irving-Williams order. The complexes were stabilized by enthalpy changes and the results suggest that the complexation is an enthalpy-driven process. The concentration distribution diagrams of the complexes are evaluated.
authors.affiliation: Department of Chemistry, Faculty of Science, Cairo University, Cairo, Egypt.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: El-Sherif
authors.forename: Mohamed M
authors.initials: MM
authors.lastname: Shoukry
authors.forename: Mohamed M A
authors.initials: MM
authors.lastname: Abd-Elgawad
mesh_terms: D000890:Anti-Infective Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D001424:Bacterial Infections / Q000188:drug therapy; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D005658:Fungi / Q000187:drug effects; D006801:Humans; D006830:Hydralazine / Q000138:chemical synthesis / Q000737:chemistry; D006835:Hydrazones / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D009181:Mycoses / Q000188:drug therapy; D013816:Thermodynamics
chemical_list: D000890:Anti-Infective Agents; D056831:Coordination Complexes; D006835:Hydrazones; D006830:Hydralazine