Two New Complexes with the Same (3,8)-Connected tfz-d Topology Based on [Co4(μ3-OH)2] Clusters and Different Aromatic Multicarboxylic Acids

Two new metal-organic frameworks (MOFs), namely, [Co-2(L-1)(bix)(mu(3)-OH)]center dot 2H(2)O (1) and [Co-2(L-2)(bix)(mu(3)-OH)]center dot 2.5H(2)O (2) (H3L1 = 5-oxyacetate isophthalic acid, H3L2 = 3,5-bis-oxyacetate-benzoic acid, bix = 1,4-bis(imidazol-1-ylmethyl)benzene), have been synthesized under hydrothermal conditions. Their structures were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra, and powder X-ray diffraction (PXRD) analysis. Both complexes 1 and 2 demonstrate identical three-dimensional (3D) (3,8)-connected tfz-d nets with (4(3))(2)(4(6).6(18).8(4)) topologies, where the tetranuclear [Co-4(mu(3)-OH)(2)] clusters act as 8-connected nodes and aromatic multicarboxylic ligands as 3-connected nodes. The results show that the ligands with different geometrical conformations can form products with the same topological structures. Their thermal and magnetic properties were also investigated.