Synthesis, structure and magnetic properties of a novel family of heterometallic nonanuclear NaI2MnIII6LnIII (Ln = Eu, Gd, Tb, Dy) complexes

Abstract

The structures and magnetic properties of four isomorphous nonanuclear heterometallic complexes [Na₂{Mn₃^III(μ₃-O²⁻)}₂Ln^III(hmmp)₆(O₂CPh)₄(N₃)₂]OH·0.5 CH₃CN·1.5H₂O are reported, where Ln^III = Eu (1), Gd (2), Tb (3) and Dy (4), H₂hmmp = 2-[(2-hydroxyethylimino)methyl]-6-methoxyphenol. Complexes 1–4 were prepared by the reactions of hmmpH₂ with a manganese salt and the respective lanthanide salt together with NaO₂CPh and NaN₃. Single-crystal X-ray diffraction analyses reveal that the six Mn^III and one Ln^III metal topology in the aggregate can be described as a bitetrahedron. The two peripheral [Mn^III₃(μ₃-O²⁻)]⁷⁺ triangles are each bonded to a central Ln^III ion with rare distorted octahedral geometry. The magnetic properties of all the complexes were investigated using variable temperature magnetic susceptibility and both antiferromagnetic and ferromagnetic interactions exist in the [Mn^III₃(μ₃-O²⁻)]⁷⁺ triangle. Weak ferromagnetic exchange between the Ln^III and Mn^III ions has been established for the corresponding Gd derivative. The Gd, Tb and Dy complexes show no evidence of slow relaxation behaviour above 2.0 K.