Acta Cryst. (2008). E64, m1351-m1352  [ doi:10.1107/S1600536808030869 ]

catena-Poly[[[aquacadmium(II)]bis(-4-hydroxypyridine-2,6-dicarboxylato)[aquacadmium(II)]di--aqua] tetrahydrate]

H. Aghabozorg, N. Ilaie, M. Heidari, F. Manteghi and H. Pasdar

Abstract: The title polymeric compound, {[Cd₂(C₇H₃NO₅)₂(H₂O)₄]·4H₂O}_n or {[Cd₂(hypydc)₂(H₂O)₄]·4H₂O}_n (where hypydcH₂ is 4-hydroxypyridine-2,6-dicarboxylic acid), was synthesized by the reaction of cadmium(II) nitrate hexahydrate with 4-hydroxypyridine-2,6-dicarboxylic acid and propane-1,3-diamine, in a 1:2:2 molar ratio in aqueous solution. The compound is a seven-coordinate binuclear polymeric complex with distorted pentagonal bipyramidal geometry around Cd^II [Cd-O = 2.247 (4)-2.474 (3) Å]. In the binuclear monomeric units, the central atoms join together by O atoms of two bridging tridentate (hypydc)^2- ligands, and the polymer propagates via two bridging water molecules that link each Cd^II centre of one monomer to the adjacent neighbour. Propane-1,3-diamine (pn) does not appear in the product but plays a role as a base. Intermolecular O-HO and C-HO hydrogen bonds, and - stacking interactions, with distances of 3.725 (3) and 3.766 (3) Å, connect the various components.

Online 30 September 2008

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