Three-Dimensional Eight- or Four-Connected Metal−Organic Frameworks Tuned by Hydrothermal Temperatures

Two novel three-dimensional (3D) metal−organic frameworks (MOFs) with cobalt(II) clusters as nodes and mixed bridging ligands as links, [Co 4 (OH) 2 (obbz) 3 (4,4‘-bpy) 2 ](4,4‘-bpy) (obbz 2- = N, N ‘-oxamidobis(benzoato), 4,4‘-bpy = 4,4‘-bipyridine) ( 1 ) and [Co 3 (H 2 O)(obbz) 3 (4,4‘-bpy) 2 ](H 2 O) 2 ( 2 ), were obtained from the same reaction mixture but tuned by different hydrothermal temperatures: the 160 °C product 1 is a 3D MOF based on the novel tetranuclear cluster node [Co 4 (OH) 2 ] 6+, displaying a new eight-connected 3 6 4 14 5 4 6 4 topology, whereas the 140 °C product 2 is a 2-fold interpenetrating 3D MOF constructed from not only the binuclear cluster node [Co 2 (μ 2 -H 2 O)] 4+ but also the mononuclear node Co 2+, showing a distorted diamond network.