Hierarchical Assembly of Coordination Macromolecules with Atypical Geometries: Gd 44 Co 28 Crown and Gd 95 Co 60 Cage.

The discovered giant clusters are always highly symmetric owing to the spontaneous assembly of one or two basic units. Herein we report the Gd 44 Co 28 crown and Gd 95 Co 60 cage, formulated as [Gd 44 Co 28 (IDA) 20 (OH) 72 (CO 3 ) 12 (OAc) 28 (H 2 O) 64 ]⋅(ClO 4 ) 24 and [Na 4 Gd 95 Co 60 (IDA) 40 (OH) 150 (CO 3 ) 40 (OAc) 58 (H 2 O) 164 ] ⋅ (ClO 4 ) 41 (H 2 IDA=iminodiacetic acid), respectively, by providing a library containing multiple low-nuclearity units. The heart-like units and crown-like tetramer found in both compounds indicate unprecedented assembly levels, leading to an atypical geometry characteristic compared to the giant clusters directly assembled by regular units. These two clusters not only significantly increase the size of Ln-Co clusters but also exhibit the enhanced magnetic entropy change at ultra-low temperatures. This work provided an effective way to fabricate cluster compounds with giant size and geometry complexity simultaneously.