Unprecedented Octanuclear DyIII Cluster Exhibiting Single-Molecule Magnet Behavior

An unprecedented Dy8 cluster, [Dy8(μ4-O)(μ3-OH)8(vht)4(NO3)2(H2O)8](NO3)4, composed of two fused and distorted [Dy4(μ3-OH)4]8+ cubane units is reported. The bridging of the two cubanes occurs through a planar μ4-O (oxide) moiety, and leads to the largest reported distortion of the Dy-O-Dy angles within a [Dy4(OH)4] cubane core. In turn, this leads to clear zero-field slow relaxation of the magnetization, characteristic of single-molecule magnets (SMMs). Further magnetic analyses suggest that the relaxation may be largely dictated by quantum tunneling of the magnetization and Raman processes.