Construction of Metal−Organic Frameworks with Tetranuclear Metal Clusters: Hydrothermal Synthesis, Structure, and Magnetic Properties WangGuan-Hua LeiYong-Qian WangNing HeRen-Ling JiaHeng-Qing HuNing-Hai XuJing-Wei 2010 Five novel coordination polymers [Co<sub>4</sub>(OABDC)<sub>2</sub>(OH)<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>]<i><sub>n</sub></i>·(H<sub>2</sub>O)<sub>4.4<i>n</i></sub> (<b>1</b>), [Ni<sub>4</sub>(OABDC)<sub>2</sub>(OH)<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>]<sub><i>n</i></sub>·(H<sub>2</sub>O)<sub>4<i>n</i></sub> (<b>2</b>) (OABDC = 5-oxyacetateisophthalate), [Co<sub>2</sub>(OABDC)(bpe)(OH)]<sub><i>n</i></sub>·(H<sub>2</sub>O)<sub>2.9<i>n</i></sub> (<b>3</b>), [Zn<sub>2</sub>(OABDC)(bpe)(OH)]<sub><i>n</i></sub>·(H<sub>2</sub>O)<sub>3.5<i>n</i></sub> (<b>4</b>) (bpe = 1,2-bis(4-pyridyl)ethylene), and [Co<sub>2</sub>(OABDC)(bpy)(OH)]<sub><i>n</i></sub>·(H<sub>2</sub>O)<sub>2.2<i>n</i></sub> (<b>5</b>) (bpy = 4,4′-bipyridine) have been acquired at similar hydrothermal conditions. All compounds are constructed from tetranuclear [M<sub>4</sub>(μ<sub>3</sub>-OH)<sub>2</sub>] (M = Co for <b>1</b>, <b>3</b>, and <b>5</b>, Ni for <b>2</b>, Zn for <b>4</b>) clusters. Compounds <b>1</b> and <b>2</b> are isomorphous, in which the M<sub>4</sub>(OH)<sub>2</sub> units act as 6-connected nodes and the frameworks are two-dimensional (2D) (3,6)-connected nets with the rare CdI<sub>2</sub> type. If considering the strong H-bond interactions between neighboring layers, both exhibit three-dimensional (3D) microporous networks with channels running along the [100] direction. Complexes <b>3</b> and <b>4</b> are also isomorphous, in which the 2D CdI<sub>2</sub>-based layer was pillared by bpe spacers; thus channels occur along the [100] direction. While adopting bpy instead of the bpe ligand, smaller channels are observed along the [100] direction for <b>5</b>. The last three compounds all feature 3D networks with one of the scarce (3,8)-connected (4<sup>3</sup>)<sub>2</sub>.(4<sup>6</sup>.6<sup>18</sup>.8<sup>4</sup>) topologies. Magnetic susceptibility measurements indicate that compound <b>1</b> shows strong antiferromagnetic behavior, while <b>2</b> exhibits strong ferromagnetic behavior.