2-Amino-4-methyl­pyridinium 4-amino­benzoate

Hong Shen; Jing-Jing Nie; Duan-Jun Xu

doi:10.1107/S1600536808014839

. 2008 May 21;64(Pt 6):o1129. doi: 10.1107/S1600536808014839

2-Amino-4-methylpyridinium 4-aminobenzoate

Hong Shen ^a, Jing-Jing Nie ^a, Duan-Jun Xu ^a,^*

PMCID: PMC2961432 PMID: 21202640

Abstract

In the structure of the title salt, C₆H₉N₂ ⁺·C₇H₆NO₂ ⁻, the 4-aminobenzoate anions are linked to adjacent anions and 2-amino-4-methylpyridinium cations via N—H⋯O hydrogen bonds, forming a three-dimensional supramolecular structure. The crystal structure also shows a weak C—H⋯O hydrogen bond between adjacent anions. Within the 4-aminobenzoate anion, the carboxylate group is twisted by 14.0 (4)° with respect to the benzene ring.

Related literature

For general background, see: Choudhury et al. (2007 ▶); Halvorson et al. (1987 ▶); Geiser et al. (1986 ▶); Geiser & Willett (1984 ▶). For related structures, see: Kaabi & Khedhiri (2004 ▶); Chtioui et al. (2006 ▶). For a description of the Cambridge Structural Database, see Allen (2002 ▶).

Experimental

Crystal data

C₆H₉N₂ ⁺·C₇H₆NO₂ ⁻
M _r = 245.28
Orthorhombic,
a = 5.5734 (14) Å
b = 8.8154 (16) Å
c = 25.374 (5) Å
V = 1246.6 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 295 (2) K
0.46 × 0.38 × 0.30 mm

Data collection

Rigaku R-AXIS RAPID IP diffractometer
Absorption correction: none
14099 measured reflections
1451 independent reflections
1126 reflections with I > 2σ(I)
R _int = 0.059

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.095
S = 1.04
1451 reflections
165 parameters
H-atom parameters constrained
Δρ_max = 0.13 e Å⁻³
Δρ_min = −0.12 e Å⁻³

Data collection: PROCESS-AUTO (Rigaku, 1998 ▶); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2002 ▶); program(s) used to solve structure: SIR92 (Altomare et al., 1993 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808014839/ng2457sup1.cif

e-64-o1129-sup1.cif^{(15.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808014839/ng2457Isup2.hkl

e-64-o1129-Isup2.hkl^{(70.1KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O2ⁱ	0.89	2.19	3.021 (3)	157
N2—H2N⋯O2	0.92	1.69	2.606 (3)	174
N3—H3A⋯O1ⁱⁱ	0.93	1.95	2.844 (3)	160
N3—H3B⋯O1	0.92	1.95	2.872 (3)	174
C3—H3⋯O2ⁱ	0.93	2.52	3.301 (3)	142

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The work was supported by the ZIJIN project of Zhejiang University, China.

supplementary crystallographic information

Comment

The presence of the outside lone-pair electrons on the pyridine-N atom suggests that 2-amino-4-methyl-pyridine is an appropriate ligand for preparing metal complexes. However a search of the Cambridge Structure Database (November 2007 update; Allen, 2002) shows that in the most cases the 2-amino-4-methyl-pyridine presents as a counter cation but does not coordinate to the metal ion (Choudhury et al., 2007; Halvorson et al., 1987; Geiser et al., 1986; Geiser & Willett, 1984). This implies that the 2-amino-4-methyl-pyridine, as a weak base, is easy to be protonated in acid condition. The crystal structures of two inorganic salt of 2-amino-4-methyl-pyridine, 2-amino-4-methyl-pyridinium phosphate (Kaabi & Khedhiri, 2004) and 2-amino-4-methyl-pyridinium arsenate (Chtioui et al., 2006), have been reported previously. Recently we prepared the title organic salt of 2-amino-4-methyl-pyridine, and its crystal structure is reported here.

The crystal of the title compound consists of 2-amino-4-methyl-pyridinium cations and amino-benzoate anions (Fig. 1). The smaller difference in C—O bond distances of the carboxyl group (Table 1) indicates the carboxyl group is deprotonated in the crystal. Within the anion the carboxyl group is twisted with respect to the benzene ring by a dihedral angle of 14.0 (4)°. In the crystal, the aminobenzoate anions are linked with both of adjacent aminobenzoate anions and aminomethylpyridinium cations via N—H···O hydrogen bonding, to form the three dimensional supramolecular structure. The crystal structure also contains weak C—H···O hydrogen bonding between adjacent anions.

Experimental

2-Amino-4-methyl-pyridine (0.054 g, 0.5 mmol) and 4-amino-benzoic acid (0.069 g, 0.5 mmol) were dissolved in ethanol (5 ml) at room temperature. The solution was filtered and light brown single crystals were obtained from the filtration after 2 weeks.