2-Amino-5-chloropyridine–benzoic acid (1/1)

In the title compound, C5H5ClN2·C7H6O2, the carboxyl group of the benzoic acid molecule is twisted away from the attached ring by 14.22 (7)°. In the crystal, the 2-amino-5-chloropyridine molecules interact with the carboxyl groups of benzoic acid molecules through N—H⋯O and O—H⋯N hydrogen bonds, forming cyclic R 2 2(8) hydrogen-bonded motifs, and linking the molecules into chains parallel to the [001] direction. Neighbouring 2-amino-5-chloropyridine molecules are also centrosymmetrically paired through C—H⋯Cl hydrogen bonds, forming another R 2 2(8) motif. The crystal structure is further stabilized by weak C—H⋯O hydrogen bonds.

In the title compound, C 5 H 5 ClN 2 ÁC 7 H 6 O 2 , the carboxyl group of the benzoic acid molecule is twisted away from the attached ring by 14.22 (7) . In the crystal, the 2-amino-5-chloropyridine molecules interact with the carboxyl groups of benzoic acid molecules through N-HÁ Á ÁO and O-HÁ Á ÁN hydrogen bonds, forming cyclic R 2 2 (8) hydrogen-bonded motifs, and linking the molecules into chains parallel to the [001] direction. Neighbouring 2-amino-5-chloropyridine molecules are also centrosymmetrically paired through C-HÁ Á ÁCl hydrogen bonds, forming another R 2 2 (8) motif. The crystal structure is further stabilized by weak C-HÁ Á ÁO hydrogen bonds.
The asymmetric unit ( Fig. 1), contains one 2-amino-5-chloropyridine molecule and one benzoic acid molecule. The 2-amino-5-chloropyridine molecule is planar, with a maximum deviation of 0.002 (1) Å for atom N1. The carboxyl group of the benzoic acid molecule is twisted away from the attached ring by 14.22 (7)° . The bond lengths (Allen et al., 1987) and angles are normal.

Experimental
A hot methanol solution (20 ml) of 2-amino-5-chloropyridine (65 mg, Aldrich) and benzoic acid (61 mg, Merck) were mixed and warmed over a heating magnetic stirrer for a few minutes. The resulting solution was allowed to cool slowly at room temperature and crystals of the title compound appeared after a few days.

Refinement
All the H atoms were located in a difference Fourier map and allowed to refine freely [N-H = 0.88 (2) (Cosier & Glazer, 1986) operating at 100.0 (1) K.
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.