Syntheses and characterizations of two 3D cobalt-organic frameworks from 2D honeycomb building blocks

The hydrothermal reaction of Co(NO3)(2)(.)6H(2)O, imidazole 4,5-dicarboxylic acid (H3IDC), and 4,4'-bipydine (bipy) under different conditions affords two interesting metal-organic compounds, {[Co-3(IDC)(2)(4,4'-bipy)(H2O)(4)](.)2H(2)O}(n) (1) and {[Co-3(IDC)(2)(4,4'-biPY)(3)](.)6H(2)O(.)DMF}(n) (2), both of which have been structurally characterized by single-crystal X-ray diffraction, elemental analysis, infrared spectroscopy, and thermogravimetric analysis. Temperature-dependent magnetic susceptibility for 1 and 2 were also studied. The "all-chair" two-dimensional honeycomb networks, structurally analogous to CFx, were linked by the bridging 4,4'-bipy ligand in compound 1 to give rise to a 2-fold interpenetrated 3D architecture. Compound 2 features a three-dimensional open framework with hexagonal channels, generated from two-dimensional graphene-like layers pillared by 4,4'-bipy. The simplest cyclic motif of the 2D networks in 1 and 2 is a 24-membered hexagonal ring consisting of six Co(II) cations and six IDC3- trianions.