Anhydrous guanidinium 3,5-dinitrobenzoate

Graham Smith,Urs D Wermuth,Jonathan M White

doi:10.1107/s1600536807002231

Abstract

Guanidinium 3,5-dinitrobenzoate, CH6N3+.C7H3N2O6-, determined at 130 K, forms a three-dimensional hydrogen-bonded structure involving all six H atoms of the guanidinium cation with oxygen acceptors of the anion including an offset cyclic R-2(2)(8) interaction with the carboxylate group.

Highlights

In (I) (Fig. 1), all six H atoms of the GU cation give hydrogen-bonding interactions with carboxylate and, to a lesser extent, nitro O acceptors of the anion (Table 1), resulting in a three-dimensional framework structure (Fig. 2). Among these is a cyclic R22(8) interaction with the two carboxylate oxygen acceptors of the anion, similar to that found in the analogous guanidinium 3,5-dinitrosalicylate, except that the two interacting species are offset rather than coplanar
H atoms involved in hydrogen-bonding interactions were located by difference Fourier methods and their positional and isotropic displacement parameters were refined
The aromatic H atoms were included in the refinement in calculated positions (C—H = 0.95 A ) using a riding-model approximation, with Uiso(H) = 1.2Ueq(C)

Summary

Structure Reports Online

Key indicators Single-crystal X-ray study T = 130 K Mean (C–C) = 0.002 A R factor = 0.030 wR factor = 0.082 Data-to-parameter ratio = 9.8. In (I) (Fig. 1), all six H atoms of the GU cation give hydrogen-bonding interactions with carboxylate and, to a lesser extent, nitro O acceptors of the anion (Table 1), resulting in a three-dimensional framework structure (Fig. 2). Among these is a cyclic R22(8) interaction with the two carboxylate oxygen acceptors of the anion, similar to that found in the analogous guanidinium 3,5-dinitrosalicylate, except that the two interacting species are offset rather than coplanar. After concentration to ca 30 ml, partial room-temperature evaporation of the hot-filtered solution gave pale-yellow crystal blocks (m.p. > 553 K)

Data collection

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