Molecular Assembly and Magnetic Dynamics of Two Novel Dy6 and Dy8 Aggregates

Complexation of dysprosium(III) with the heterodonor chelating ligand o-vanillin picolinoylhydrazone (H(2)ovph) in the presence of a carbonato ligand affords two novel Dy-6 and Dy-8 clusters, namely, [Dy-6(ovph)(4)(Hpvph)(2)Cl-4 (H2O)(2)(CO3)(2)]center dot CH3OH center dot H2O center dot CH3CN (2) and [Dy-8(ovph)(8)(CO3)(4)(H2O)(8)]center dot 12CH(3)CN center dot 6H(2)O (3). Compound 2 is composed of three petals of the Dy-2 units linked by two carbonato ligands, forming a triangular prism arrangement, while compound 3 possesses an octanuclear core with an unprecedented tub conformation, in which Dy(ovph) fragments are attached to the sides of the carbonato core. The static and dynamic magnetic properties are reported and discussed. In the Dy-6 aggregate, three Dy-2 "skeletons", having been well preserved (see the scheme), contribute to the single-molecule-magnet behavior with a relatively slow tunneling rate, while the Dy-8 cluster only exhibits a rather small relaxation barrier.