Acta Cryst. (2012). E68, o124-o125 [ doi:10.1107/S160053681105286X ]
Abstract: In the title molecular salt, C5H7N2+·C8H5N2O7-, the 2-aminopyridinium cation is essentially planar, with a maximium deviation of 0.015 (1) Å, while the 2-methoxycarbonyl-4,6-dinitrophenolate anion is slightly twisted away from planarity, with a maximium deviation of 0.187 (1) Å. Deprotonation of the hydroxy O atom was observed. The cation and anion are connected by four bifurcated N-H(O,O) hydrogen bonds, forming a molecular proton-transfer adduct. The dihedral angle between the pyridinium ring in the cation and the benzene ring in the anion is 3.65 (6)°. Every adduct connects to six neighboring adducts by N-HO and C-HO hydrogen bonds, yielding extended layers parallel to the bc plane. There is a weak - interaction between the benzene rings of two neighboring anions; the interplanar spacing and the centroid-centroid separation are 3.309 (1) and 3.69 (1) Å, respectively.
Online 14 December 2011
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