Heterotrinuclear complexes containing d- and f-block elements: synthesis and structural characterisation of novel lanthanide(III)-nickel(II)-lanthanide(III) compounds bridged by oxamidate

The reaction of lanthanide(III) ions with a tripodal ligand HB(pz)(3)(-) [= hydrotris(pyrazol-1-yl)borate] and a 'complex ligand' [NiL](2-) [L = tdo(4-) or edo(4-), where H(4)tdo = trimethylenebis(oxamide) and H(4)edo = ethylenebis(oxamide)] in aqueous solution produced the novel 3d-4f heterotrinuclear complexes [NiL{Ln[HB(pz)(3)](2)}(2)] [abbreviated as Ni(tdo)Ln(2) (Ln = Eu, Tb or Yb) and Ni(edo)Ln(2) (Ln = Sm to Lu)]. The crystal structures of Ni(tdo)Yb-2 and Ni(edo)Lu-2 have been determined by X-ray diffraction method. The Ni atoms in both have a square-planar environment and the Ln atoms have eight-co-ordinated square-antiprismatic co-ordination geometries.