Mixed-anion templated cage-like lanthanide clusters: Gd27 and Dy27

Two nanoscale clusters whose metals are exclusively lanthanides, and whose formulas are [(ClO4)@Ln(27)(mu(3)-OH)(32)(CO3)(8)(CH3CH2COO)(20)(H2O)(40)]center dot(ClO4)(12)center dot(H2O)(50) (abbreviated as Ln(27). 1, Gd; 2, Dy), were synthesized. Structural analysis showed that the 27 lanthanide ions were organized into a beautiful cage-like structure templated by eight CO32- groups, which were generated from the fixation of atmospheric CO2. Acting as a template guest, one ClO4- group was encapsulated in the Ln(27) cage. The Ln(27) compound is by far the largest odd-numbered lanthanide cluster synthesized to date. In magnetization studies of these two compounds, isotropic Gd-27 exhibited a large MCE of 41.8 J kg(-1) k(-1) at 2 K for Delta H = 7 T, while anisotropic Dy-27 displayed a slow relaxation of its magnetization.