Acta Cryst. (2009). E65, m1265-m1266  [ doi:10.1107/S1600536809038756 ]

Synchrotron study of poly[[di--aqua(-2,2'-bipyridyl-5,5'-dicarboxylato)dipotassium] dihydrate]

J. A. Bertke, A. G. Oliver and K. W. Henderson

Abstract: The title compound, {[K₂(C₁₂H₆N₂O₄)(H₂O)₂]·2H₂O}_n, forms a three-dimensional coordination polymer in the solid state. The asymmetric unit consists of one K⁺ ion, half of a 2,2'-bipyridyl-5,5'-dicarboxylate ligand, one coordinated water molecule and one solvent water molecule. The K⁺ ion is 7-coordinated by the oxygen atoms of two water molecules and by five oxygen atoms of four carboxylate groups, one of which is chelating. The extended structure can be described as a binodal network in which each K⁺ is a six-connected node, bonding to four carboxylate groups and two bridging water molecules, and the 2,2'-bipyridyl-5,5'-dicarboxylate linkers are eight-connected nodes, with each carboxylate group bridging four metal centers. Overall, this arrangement generates a complex network with point symbol {3⁴.4¹².5¹²}{3⁴.4⁴.5⁴.6³}₂. Both of the bridging water molecules participate as donors in hydrogen-bonding interactions; one to solvent water molecules and a second to an oxygen atom of a carboxylate group.

Online 30 September 2009

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