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, [Co4(OH)2(obbz)3(4,4‘-bpy)2](4,4‘-bpy) (obbz2- = N,N‘-oxamidobis(benzoato), 4,4‘-bpy = 4,4‘-bipyridine) (1) and [Co3(H2O)(obbz)3(4,4‘-bpy)2](H2O)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 [Co4(OH)2]6+, displaying a new eight-connected 364145464 topology, whereas the 140 °C product 2 is a 2-fold interpenetrating 3D MOF constructed from not only the binuclear cluster node [Co2(μ2-H2O)]4+ but also the mononuclear node Co2+, showing a distorted diamond network.