Acta Cryst. (2007). E63, m1710-m1711  [ doi:10.1107/S1600536807023367 ]

Piperazinediium bis(pyridine-2,6-dicarboxylato)nickelate(II) tetrahydrate

H. Aghabozorg, J. Attar Gharamaleki, P. Ghasemikhah, M. Ghadermazi and J. Soleimannejad

Abstract: The reaction of nickel(II) nitrate hexahydrate with the proton-transfer compound piperazinediium pyridine-2,6-dicarboxylate, or (pipzH₂)(pydc) (in which pipz is piperazine and pydcH₂ is pyridine-2,6-dicarboxylic acid), in aqueous solution leads to the formation of the title compound, (pipzH₂)[Ni(pydc)₂]·4H₂O or (C₄H₁₂N₂)[Ni(C₇H₃NO₄)₂]·4H₂O. The anion is a six-coordinate complex with a distorted octahedral geometry around Ni^II. The torsion angles show that the two (pydc)^2- units are almost perpendicular to each other. Considerable - stacking interactions between two aromatic rings of (pydc)^2-, with distances of 3.4686 (14) and 3.5034 (14) Å, are observed. Extensive intermolecular O-HO, N-HO and C-HO hydrogen bonding involving the (pydc)^2- ligand, (pipzH₂)²⁺ as counter-ion and uncoordinated water molecules connect the various components into a supramolecular structure.

Online 26 May 2007

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