Research Article: 4-Meth­oxy­benzamidinium 2,6-dimeth­oxy­benzoate

Date Published: February 01, 2012

Publisher: International Union of Crystallography

Author(s): Gustavo Portalone.


The title compound, C8H11N2O+·C9H9O4−, was synthesized by the reaction of 4-meth­oxy­benzamidine (4-amidino­anisole) and 2,6-dimeth­oxy­benzoic acid. The structure consists of non-planar pairs of hydrogen-bonded 4-meth­oxy­benzamidinium cations and 2,6-dimeth­oxy­benzoate anions. In the cation, the amidinium group is tilted by 27.94 (10)° with respect to the benzene ring. In the anion, the sterically bulky ortho-meth­oxy substituents force the carb­oxy­ate group to be twisted away from the plane of the benzene ring by 73.24 (6)°. The ions are further associated in the crystal into chains along the b-axis direction by inter­molecular N—H⋯O hydrogen bonds.

Partial Text

For the biological and pharmacological relevance of benzamidine, see: Marquart et al. (1983 ▶); Sprang et al. (1987 ▶); Bode et al. (1990 ▶); Powers & Harper (1999 ▶); Grzesiak et al. (2000 ▶). For the structure of benzamidine, see: Barker et al. (1996 ▶). For supra­molecular association in proton-transfer adducts containing benzamidinium cations, see; Papoutsakis et al. (1999 ▶); Portalone (2008 ▶, 2010 ▶). For the structure of benzdiamidine, see: Jokić et al. (2001) ▶. For the ortho­rhom­bic and tetra­gonal polymorphs of 2,6-dimeth­oxy­benzoic acid, see: Swaminathan et al. (1976 ▶); Bryan & White (1982 ▶); Portalone (2009 ▶, 2011 ▶). For the analysis of benzene ring deformations induced by substitution, see: Schultz et al. (1993 ▶); Portalone et al. (1998 ▶); For computation of ring patterns formed by hydrogen bonds in crystal structures, see: Etter et al. (1990 ▶); Bernstein et al. (1995 ▶); Motherwell et al. (1999 ▶).