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

Abstract

In the presence of dicyanamide and N-butyldiethanolamine (bdeaH2), Fe(III) and Dy(III) precursors self-assemble into the charge-neutral coordination cluster [Fe6Dy3(ib)9(bdea)6(MeO)6]·MeOH (1) (ib: isobutyrate) featuring an approximately C3-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.