Construction of Metal−Organic Frameworks with Tetranuclear Metal Clusters: Hydrothermal Synthesis, Structure, and Magnetic Properties
2010-02-03T00:00:00Z (GMT) by
Five novel coordination polymers [Co4(OABDC)2(OH)2(H2O)4]n·(H2O)4.4n (1), [Ni4(OABDC)2(OH)2(H2O)4]n·(H2O)4n (2) (OABDC = 5-oxyacetateisophthalate), [Co2(OABDC)(bpe)(OH)]n·(H2O)2.9n (3), [Zn2(OABDC)(bpe)(OH)]n·(H2O)3.5n (4) (bpe = 1,2-bis(4-pyridyl)ethylene), and [Co2(OABDC)(bpy)(OH)]n·(H2O)2.2n (5) (bpy = 4,4′-bipyridine) have been acquired at similar hydrothermal conditions. All compounds are constructed from tetranuclear [M4(μ3-OH)2] (M = Co for 1, 3, and 5, Ni for 2, Zn for 4) clusters. Compounds 1 and 2 are isomorphous, in which the M4(OH)2 units act as 6-connected nodes and the frameworks are two-dimensional (2D) (3,6)-connected nets with the rare CdI2 type. If considering the strong H-bond interactions between neighboring layers, both exhibit three-dimensional (3D) microporous networks with channels running along the  direction. Complexes 3 and 4 are also isomorphous, in which the 2D CdI2-based layer was pillared by bpe spacers; thus channels occur along the  direction. While adopting bpy instead of the bpe ligand, smaller channels are observed along the  direction for 5. The last three compounds all feature 3D networks with one of the scarce (3,8)-connected (43)2.(46.618.84) topologies. Magnetic susceptibility measurements indicate that compound 1 shows strong antiferromagnetic behavior, while 2 exhibits strong ferromagnetic behavior.