A Spontaneous Condensation Sequence from a {Fe6Dy3} Wheel to a {Fe7Dy4} Globe

In the presence of dicyanamide and N-butyldiethanol-amine (bdeaH(2)), Fe(III) and Dy(III) precursors self-assemble into the charge-neutral coordination cluster [Fe6Dy3(ib)(9)(bdea)(6)(MeO)(6)]center dot MeOH (1) (ib: isobutyrate) featuring an approximately C-3-symmetric wheel of edge-sharing FeO6 and DyO6N2 polyhedra. This is followed by a remarkable self-induced conversion of this cluster into the highly condensed globe-shaped coordination cluster [Fe7Dy4O4(OH)(3)(ib)(9.25)(bdea)(6)(NO3)(0.75)(H2O)] (2) in methanolic solution under ambient conditions. The transition from {Fe6Dy3} to {Fe7Dy4} coincides with a slowdown of the clusters' magnetization dynamics, as evident from a shift of the onset of significant out-of-phase components of their magnetic ac susceptibility from 3.6 K up to 12 K (1000 Hz) in the absence of a static bias field.