Received 30 May 2013
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)°.
For the biological and pharmacological relevance of benzamidine, see: Powers & Harper (1999). For structural analysis of proton-transfer adducts containing molecules of biological interest, see: Portalone (2010, 2013). For the supramolecular association in proton-transfer adducts containing benzamidinium cations, see: Portalone (2010, 2012, 2013); Irrera & Portalone (2012, 2013); Irrera et al. (2012). For 2-methoxybenzoic acid derivatives, see: Portalone (2011). For hydrogen-bond motifs, see: Bernstein et al. (1995).
Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: WinGX (Farrugia, 2012).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: NK2209 ).
Agilent (2011). CrysAlis PRO. Agilent Technologies Ltd, Abingdon, England.
Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115-119.
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.
Irrera, S., Ortaggi, G. & Portalone, G. (2012). Acta Cryst. C68, o447-o451.
Irrera, S. & Portalone, G. (2012). Acta Cryst. E68, o3083.
Irrera, S. & Portalone, G. (2013). Acta Cryst. E69, o56.
Portalone, G. (2010). Acta Cryst. C66, o295-o301.
Portalone, G. (2011). Acta Cryst. E67, o3394-o3395.
Portalone, G. (2012). Acta Cryst. E68, o268-o269.
Portalone, G. (2013). Acta Cryst. E69, o14-o15.
Powers, J. C. & Harper, J. W. (1999). Proteinase inhibitors, edited by A. J. Barrett & G. Salvesen, pp. 55-152. Amsterdam: Elsevier.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.