(IUCr) Crystallography Journals Online

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Acta Cryst. (2005). E61, o431-o433 [ doi:10.1107/S1600536805001765 ]

1,10-Phenanthrolin-1-ium 2-carboxy-4-nitrobenzoate

M.-L. Guo

Abstract: The cation of the title salt, C₁₂H₉N ${}_{2}^{\,\,+}$ ·C₈H₄NO ${}_{6}^{\,\,- }$ , is a monoprotonated 1,10-phenanthroline molecule, whereas its anion is a monodeprotonated 4-nitrophthalic acid molecule. There is a strong, almost symmetrical, intramolecular hydrogen bond linking the O atoms of neighbouring carboxylate groups within the anion [O-H = 1.13 (4) Å, HO = 1.27 (4) Å, OO = 2.395 (3) Å and O-HO = 173 (4)°]. An N-HO bond [N-H = 1.00 (3) Å, HO = 1.70 (3) Å, NO = 2.668 (3) Å and N-HO = 160 (3)°] is responsible for formation of ion pairs, which are further loosely aggregated into a three-dimensional framework via C-HO and [pi] - [pi] interactions.

Online 29 January 2005