Acta Cryst. (2009). E65, m186-m187  [ doi:10.1107/S1600536809000828 ]

Hydroxonium hydrate tris(2,4,6-triamino-1,3,5-triazin-1-ium) bis[bis(pyridine-2,6-dicarboxylato)cuprate(II)] pyridine-2,6-dicarboxylic acid hexahydrate

H. Aghabozorg, J. Attar Gharamaleki, M. M. Olmstead, Z. Derikvand and S. Hooshmand

Abstract: The reaction of copper(II) nitrate hexahydrate with pyridine-2,6-dicarboxylic acid (pydcH₂) and 2,4,6-triamino-1,3,5-triazine (melamine) in aqueous solution in a 1:2:2 molar ratio gave the title compound, (H₅O₂)(C₃H₇N₆)₃[Cu(C₇H₃NO₄)₂]₂·C₇H₅NO₄·6H₂O. The hydroxonium hydrate (H₅O₂)⁺, also known as the Zundel cation, resides on a twofold rotation axis. The O-H distance is 1.274 (14) Å, the OO distance is 2.518 (5) Å, and the O-H-O angle is 162 (8)°. One of the melamine H⁺ cations, the uncoordinated pydcH₂, and two water molecules also reside on crystallographic twofold axes. The Cu^II atom has a tetragonally distorted octahedral coordination environment. The structure features extensive hydrogen bonding, with 21 distinct interactions. There is also a centrosymmetric C=O interaction with an Ocentroid distance of 3.288 (3) Å. The structure is similar to a mixed-valence manganese(II/III) structure but shows interesting differences in the metal-atom coordination. One of the water molecules is equally disordered with respect to a twofold axis.

Online 14 January 2009

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