RESUMO
Reactions of lanthanide(III) perchlorate (Ln = Dy, Tb, and Gd), nickel(II) acetate, and ditopic ligand 2-(benzothiazol-2-ylhydrazonomethyl)-6-methoxyphenol (H(2)L) in a mixture of methanol and acetone in the presence of NaOH resulted in the successful assembly of novel Ln(2)Ni(2) heterometallic clusters representing a new heterometallic 3d-4f motif. Single-crystal X-ray diffraction reveals that all compounds are isostructural, with the central core composed of distorted [Ln(2)Ni(2)O(4)] cubanes of the general formula [Ln(2)Ni(2)(µ(3)-OH)(2)(OH)(OAc)(4)(HL)(2)(MeOH)(3)](ClO(4))·3MeOH [Ln = Dy (1), Tb (2), and Gd (3)]. The magnetic properties of all compounds have been investigated. Magnetic analysis on compound 3 indicates ferromagnetic Gd···Ni exchange interactions competing with antiferromagnetic Ni···Ni interactions. Compound 1 displays slow relaxation of magnetization, which is largely attributed to the presence of the anisotropic Dy(III) ions, and thus represents a new discrete [Dy(2)Ni(2)] heterometallic cubane exhibiting probable single-molecule magnetic behavior.
RESUMO
A discrete dysprosium cubane has been prepared and structurally characterized. Slow relaxation of magnetization in this complex is observed, which may stimulate further investigations into the dynamics of magnetization in lanthanide clusters with different topologies.