A diabolo-shaped Dy9 cluster: synthesis, crystal structure and magnetic properties.

The reaction of Dy(NO3)3·6H2O with the ligand 2-((1-hydroxybutan-2-ylimino)methyl)phenol (H2L, Scheme 1) generates the nonanuclear compound [Dy9L8(μ3-OH)8(μ4-OH)2(CH3OH)8](OH)(CH3OH)3(Dy9), whose single-crystal X-ray structure reveals the presence of two square pyramidal pentanuclear units assembled viathe apical metal center. The square pyramidal core of a previously reported [Dy5(μ4-OH)(μ3-OH)4(μ-η2-Ph2acac)4(η2-Ph2acac)6] (Dy5; Ph2acac = dibenzoylmethanide), is structurally related to those herein described; however, the magnetic properties of Dy9and Dy5are drastically different. Indeed, Dy5shows slow relaxation of magnetization while no out-of-phase ac signal is noticed for Dy9. The underlying mechanism is not clear due to the complexity of such systems; however, the different anisotropy of the respective structures, which is dictated by the combination of the metal topology, the ligands involved and the structural parameters of the molecule, is mostly responsible for the distinctive relaxation dynamics observed. [ABSTRACT FROM AUTHOR]