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inorganic compounds
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The crystal structure of a lanthanum polyoxotungstate complex, viz. heptaammonium disodium decatungstolanthanate hexadecahydrate, Na2(NH4)7[La<(W5O18)2]·16H2O, has been determined by single-crystal X-ray diffraction at 100 (2) K in the space group C2/c. The [La(W5O18)2]9- polyoxoanion has the central La3+ cation located on a twofold rotation axis. The close packing of the polyoxoanion-supported lanthanum(III) complexes with Na+ and NH4+ cations leads to the formation of several intersecting undulating channels, where the water molecules of crystallization are located and involved in strong hydrogen bonds.
metal-organic compoundsOpen access
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The crystal structure of the title compound, polymeric hexaaquacobalt(II) diaquadioxodi-μ2-pyrazine-bis[μ3-N-(phosphonomethyl)iminodiacetato]cobalt(II)divanadate(IV) dihydrate, {[Co(H2O)6][CoV2(C3H4O8P)2(C4H4N2)2(H2O)2]·2H2O}n, is the first example of a two-dimensional hybrid framework containing centrosymmetric dimeric [V2O2(pmida)2]4− anionic units [H4pmida is N-(phosphonomethyl)iminodiacetic acid]. The structure contains two crystallographically unique cobalt(II) centres, both located at inversion centres and exhibiting Jahn–Teller-distorted octahedral coordination geometries. One Co2+ cation establishes physical links between adjacent [V2O2(pmida)2]4− anionic units, forming one-dimensional anionic ribbons which run along the [010] direction, {[Co(H2O)2][V2O2(pmida)2]}n2n−. Pyrazine ligands, with their centroids located at inversion centres, bridge the above-mentioned Co2+ centres, forming {[Co(H2O)2][V2O2(pmida)2]}n2n− anionic layers which alternate along the [001] direction with [Co(H2O)6]2+ cations and the water molecules of crystallization. An extensive and highly directional hydrogen-bonded network interconnects the structural components.
metal-organic compoundsOpen access
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The room-temperature crystal structure of the title compound, [Cu(H2pmida)(phen)]·3H2O [where H2pmida2− is hydrogen N-(phosphonomethyl)iminodiacetate, C5H10NO7P2−, and phen is 1,10-phenanthroline, C12H8N2], was recently determined by Pei Lu, Ke, Li, Qin, Zhou, Wu & Du [Struct. Chem. (2004), 15, 207–210]. We report here a redetermination, at 180 (2) K, with greatly improved precision. Hydrogen bonds lead to the formation of one-dimensional tapes which run along the [100] direction of the unit cell. Adjacent tapes are interconnected via π–π offset stacking (between the 1,10-phenanthroline ligands) and by hydrogen bonds involving the water molecules of crystallization.
