DINUCLEAR NICKEL(II) COMPLEX OF A NOVEL OXAMIDO LIGAND AS A CHELATINGAGENT

The dinuclear nickel(II) complex of an oxamide ligand reacted as a che lating ligand with transition metal cations to yield either tetra- or polymetallic complexes. The parent oxamido ligand is decadentate hexab asic and contains two symmetrical sets of N2O3 coordinating sites. The inner N2O3 sites of each set are coordinated to a nickel(II) cation. The outer O2O sites are available to coordinate to other metal cations . The reactions of the parent complex [(H2L)Ni-2].EtOH with Ni(II), Co (II), Mn(II), UO2(VI) and Fe(III) cations yielded the following produc ts: [LNi2M2Cl2(OH2)(4)], M = Ni(II) or Mn(II), [(HL)Ni2CoCl(OH2)(2)](n ), [LNi2UO2(MeOH)](n) and [LNi2Fe3Cl7(OH2)(2)](2). The products were c haracterized by elemental analyses, IR, UV-Visible and mass spectra. I n addition the values of their magnetic moments indicated antiferromag netic interactions between neighbouring metal cations. The magnetic ex change takes place via the oxamido linkage and either the chlorine and /or oxygen bridges.