title: Synthesis and spectroscopic studies of 2,5-hexanedione bis(isonicotinylhydrazone) and its first raw transition metal complexes.
abstract: New VO(2+), Mn(2+), Co(2+), Ni(2+) Cu(2+) and Zn(2+) complexes of 2,5-hexanedione bis(isonicotinylhydrazone) [H(2)L] have been synthesized and characterized. The analyses confirmed the formulae: [VO(L)].H(2)O, [Mn(2)(H(2)L)Cl(2)(H(2)O)(6)]Cl(2), [Co(L)(H(2)O)(2)].2H(2)O, [Ni(HL)(OAc)].H(2)O, [Cu(L)(H(2)O)(2)].2H(2)O, [Cu(L)].2H(2)O and [Zn(L)(H(2)O)(2)]. The formulae of [Ni(HL)(OAc)].H(2)O, [Zn(L)(H(2)O)(2)] and [Mn(2)(H(2)L)Cl(2)(H(2)O)(6)]Cl(2), are supported by mass spectra. The molecular modeling of H(2)L is drawn and showed intramolecular hydrogen bonding. The ligand releases two protons during reaction from the two amide groups (NHCO) and behaves as a binegative tetradentate (N(2)O(2)); good evidence comes from the (1)H NMR spectrum of [Zn(L)(H(2)O)(2)]. The ligand has a buffering range 10-12 and pK's of 4.62, 7.78 and 9.45. The magnetic moments and electronic spectra of all complexes provide a square-planar for [Cu(L)].2H(2)O, square-pyramidal for [VO(L)].H(2)O and octahedral for the rest. The ESR spectra support the mononuclear geometry for [VO(L)].H(2)O and [Cu(L)(H(2)O)(2)].2H(2)O. The thermal decomposition of the complexes revealed the outer and inner solvents where the end product in most cases is metal oxide.
authors.affiliation: Chemistry Department, Faculty of Science, Mansoura University, Mansoura, Dakhalia 35516, Egypt. aelasmy@yahoo.com
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: El-Asmy
authors.forename: A Z
authors.initials: AZ
authors.lastname: Al-Abdeen
authors.forename: W M Abo
authors.initials: WM
authors.lastname: El-Maaty
authors.forename: M M
authors.initials: MM
authors.lastname: Mostafa
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D004583:Electrons; D006835:Hydrazones / Q000138:chemical synthesis* / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics; D013058:Mass Spectrometry; D008958:Models, Molecular; D013055:Spectrophotometry, Infrared; D013696:Temperature; D013818:Thermogravimetry; D028561:Transition Elements / Q000737:chemistry*
chemical_list: C550480:2,5-hexanedione bis(isonicotinylhydrazone); D056831:Coordination Complexes; D006835:Hydrazones; D008024:Ligands; D028561:Transition Elements