Acta Cryst. (2013). E69, o1114-o1115 [ doi:10.1107/S1600536813016395 ]
Abstract: The title molecular salt, C7H9N2+.C8H7O3-, was synthesized by reaction between benzamidine (benzenecarboximidamide) and 2-methoxybenzoic acid. In the cation, the amidinium group has two similar C-N bonds [1.3070 (17) and 1.3145 (16) Å] and is almost coplanar with the benzene ring, making a dihedral angle of 5.34 (12)°. In the anion, the methoxy substituent forces the carboxylate group to be twisted by 69.45 (6)° with respect to the plane of the aromatic fragment. In the crystal, the components are connected by two N+-HO- (±)CAHB (charge-assisted hydrogen bonds), forming centrosymmetric ionic dimers with graph-set motif R22(8). These ionic dimers are then joined in ribbons running along the b-axis direction by another R42(8) motif involving the remaining N+-HO- hydrogen bonds. Remarkably, at variance with the well known carboxylic dimer R22(8) motif, the carboxylate-amidinium pair is not planar, the dihedral angle between the planes defined by the CN2+ and CO2- atoms being 18.57 (12)°.
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