Preparation and characterization of new nickel(II), cobalt(II) and copper(II) complexes of 3,11-diacetyl-2,12-dioxo-5,9-diazatrideca-3,11-diene; reactivity towards ammonia, 1,2-diaminopropane, hydroxylamine and copper(II) acetylacetonate compounds

• Published in: Journal of coordination chemistry 2004-04, Vol.57 (6), p.509-524
• Main Authors: El-Tabl, Abdou S., Issa, Raafat M.
• Format: Article
• Language: English
• Subjects: β-Diketones
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958970410001696816

The interaction of the potentially binucleating enaminoketone, ligand 3,11-diacetyl-2,12-dioxo-5,9-diazatrideca-3,11-diene, towards nickel(II), cobalt(II) and copper(II) ions yields square planar complexes. The interaction of the complexes with ammonia, 1,2-diaminopropane, hydroxylamine and copper(II) acetylacetonate has been investigated. The complexes have been characterized by elemental analyses, UV-vis and IR spectroscopy, molar conductances, mass spectra, 1 H NMR, D.T.A., magnetic and ESR measurements. The molar conductances in DMF indicate that the complexes are non-ionic. Exposing nickel(II) complex (2) in CD 3 OD/D 2 O (10%) to 60 Co γ-rays at 77 K using a 0.2216 M rad h −1 dose, yields a nickel(I), d 9 species with a ground state. The spectrum shows that annealing above 77 K leads to a low-spin, nickel(III), d 7 species with a ground state. The cobalt(II) complex (3) shows a spectrum with g ⊥  > g || , indicating a ground state; however, the copper(II) complex (4) shows a spectrum with g ||  > g ⊥ , indicating a ground state. The redox properties of the copper(II) complexes (4 and 13) are discussed.