Poly[hemi(ethyl-enediammonium) [di-μ-oxalato-indium(III)] dihydrate]

In title compound, {(C₂H₁₀N₂)_0.5[In(C₂O₄)₂]·2H₂O}_n, the unique In^III ion is coordinated by eight O atoms from four oxalate ligands in a distorted square-anti­prismatic environment. The doubly bis-chelating oxalate ligands act as bridging ligands connecting symmetry-related In^III ions and forming a three-dimensional open framework structure. Ethyl­enediammonium cations and water mol­ecules occupy the voids within the structure. The unique ethyl­enediammonium cation and one water mol­ecule both lie on a twofold rotation axis. One of the other two water mol­ecules residing on general crystallographic sites was refined as disordered with half occupancy. In the crystal structure, cations and water mol­ecules are linked to the anionic framework via inter­molecular O—H⋯O and N—H⋯O hydrogen bonds.

Pillared-Layer Microporous Metal−Organic Frameworks Constructed by Robust Hydrogen Bonds. Synthesis, Characterization, and Magnetic and Adsorption Properties of 2,2‘-Biimidazole and Carboxylate Complexes

Two new isostructural complexes [M(H2biim)3][M(btc)(Hbiim)].2H2O (M = Co, (1); M = Ni, (2)) (btc = 1,3,5-benzenetricarboxylate; H2biim = 2,2'-biimidazole) have been synthesized and characterized by single-crystal X-ray diffraction. They present a unique structure consisting of two distinct units: the monomeric cations [M(H2biim)3]2+ and the two-dimensional (2D) anionic polymer [M(Hbiim)(btc)]2-. In the anionic moiety, the Hbiim- monoanion is simultaneously coordinated to one metal atom in a bidentate mode and further to another metal atom in a monodentate mode. The imidazolate groups bridge the two adjacent metal ions into a helical chain which is further arranged in left- and right-handed manners. These chains are bridged by btc ligands into a 2D brick wall structure. The most interesting aspect is that the [M(H2biim)3]2+ cations act as pillars and link the anionic layers via robust heteromeric hydrogen-bonded synthons (9) and (7) formed by the uncoordinated oxygen atoms of carboxylate groups and the H2biim ligands, resulting in a microporous metal-organic framework with one-dimensional (1D) channels (ca. 11.85 angstroms x 11.85 angstroms for 1 and 11.43 angstroms x 11.43 angstroms for 2). Magnetic properties of these two complexes have also been studied in the temperature range of 2-300 K, and their magnetic susceptibilities obey the Curie-Weiss law in the temperature range of 20-300 K (for 1) and 2-300 K (for 2), respectively, showing anti-ferromagnetic coupling through imidazolate bridging. Taking into consideration the Heisenberg infinite chain model as well as the possibility of chain-to-chain and chain-to-cation interactions, the anti-ferromagnetic exchange of 2 is analyzed via a correction for the molecular field, giving the values of g(cat) = 2.296, g(Ni) = 2.564, J = -13.30 cm(-1), and zJ' = -0.017 cm(-1). The microporous frameworks are stable at ca. 350 degrees C. They do not collapse after removal of the guest water molecules in the channels, and they adsorb methanol molecules selectively.