Coordination structures of lanthanide(III) and uranyl(VI) nitrato complexes with N,N′-dimethyl- N,N′-dibutylmalonamide. Part II

Abstract

The coordination structures of lanthanide(III) and uranyl(VI) nitrato complexes with N,N′-dimethyl- N,N′-dibutylmalonamide (DMDBMA) were investigated in terms of 1H, 13C and 14N NMR measurements, infrared spectrum, molar conductivity measurement, absorption spectrum, fluorescence spectrum, magnetic susceptibility measurement and thermal analysis. The chemical formulae of the isolated lanthanide(III) and uranyl(VI) nitrato-DMDBMA complexes are Ln(NO 3) 3 · 2DMDBMA and UO 2(NO 3) 2 · DMDBMA, respectively. The DMDBMA coordinates to the lanthanide(III) and uranyl(VI) ions, with the oxygen atoms of carbonyl group and nitrate ions coordinate to the central metal ions in a bidentate manner. For the lanthanide(III) nitrato complexes, the coordination number is ten, and a change of the coordination structure occurs between the lighter and heavier complexes. The uranyl(VI) nitrato-DMDBMA complex has an eight-coordinated structure with the uranyl group surrounded by six oxygen atoms, four from the bidentate nitrate groups and two from the bidentate DMDBMA, lying in the plane perpendicular to the axial uranyl group.