Synthesis, structure and magnetic properties of a novel family of heterometallic nonanuclear Na(2)(I)Mn(6)(III)Ln(III) (Ln = Eu, Gd, Tb, Dy) complexes

The structures and magnetic properties of four isomorphous nonanuclear heterometallic complexes [Na-2{Mn-3(III)(mu(3)-O2-)}(2)Ln(III)(hmmp)(6)(O2CPh)(4)(N-3)(2)]OH center dot 0.5 CH3CN center dot 1.5H(2)O are reported, where Ln(III) = Eu (1), Gd (2), Tb (3) and Dy (4), H(2)hmmp = 2-[(2-hydroxyethylimino) methyl]-6-methoxyphenol. Complexes 1-4 were prepared by the reactions of hmmpH(2) 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-III (3)(mu(3)-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-III (3)(m(3)-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.