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 H₄tdo = trimethylenebis(oxamide) and H₄edo = ethylenebis(oxamide)] in aqueous solution produced the novel 3d-4f heterotrinuclear complexes [NiL{Ln[HB(pz)₃]₂}₂] [abbreviated as Ni(tdo)Ln₂ (Ln = Eu, Tb or Yb) and Ni(edo)Ln₂ (Ln = Sm to Lu)]. The crystal structures of Ni(tdo)Yb₂ and Ni(edo)Lu₂ 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.