3-Amino­pyridin-1-ium 3-carb­oxy­benzo­ate

Jose J Campos-Gaxiola; Simón Hernández-Ortega; David Morales-Morales; Adriana Cruz Enríquez

doi:10.1107/S1600536812016108

. 2012 Apr 21;68(Pt 5):o1444. doi: 10.1107/S1600536812016108

3-Aminopyridin-1-ium 3-carboxybenzoate

Jose J Campos-Gaxiola ^a, Simón Hernández-Ortega ^b,^*, David Morales-Morales ^b, Adriana Cruz Enríquez ^a

PMCID: PMC3344561 PMID: 22590323

Abstract

In the title organic salt, C₅H₇N₂ ⁺·C₈H₅O₄ ⁻, the carboxylic group is nearly coplanar with the benzene ring [dihedral angle 1.9 (4)°] whereas the carboxylate group is twisted relative to the benzene ring by 13.6 (4)°. In the crystal, N-H⋯O and O—H⋯O hydrogen bonds connect the components into a three-dimensional framework consisting of stacks of alternating pairs of anions and cations exhibiting π–π stacking interactions with centroid–centroid distances in the range 3.676 (2)–3.711 (1) Å. The π–π stacks extend along [110] and [-110].

Related literature

For background to crystal engineering with carboxylic acids and pyridine, see: Aakeröy & Salmon (2005 ▶); Almarsson & Zaworotko (2004 ▶); Mohamed et al. (2009 ▶); Sarma et al. (2009 ▶).

Experimental

Crystal data

C₅H₇N₂ ⁺·C₈H₅O₄ ⁻
M _r = 260.25
Monoclinic,
a = 11.9282 (13) Å
b = 8.3715 (9) Å
c = 13.1421 (14) Å
β = 113.138 (2)°
V = 1206.8 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 298 K
0.42 × 0.28 × 0.19 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer
9652 measured reflections
2216 independent reflections
1668 reflections with I > 2σ(I)
R _int = 0.065

Refinement

R[F ² > 2σ(F ²)] = 0.055
wR(F ²) = 0.154
S = 1.05
2216 reflections
184 parameters
4 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.38 e Å⁻³

Data collection: SMART (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812016108/gk2468sup1.cif

e-68-o1444-sup1.cif^{(20.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812016108/gk2468Isup2.hkl

e-68-o1444-Isup2.hkl^{(109KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812016108/gk2468Isup3.cml

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
O1—H1⋯O3ⁱ	0.86 (1)	1.76 (1)	2.616 (2)	173 (3)
N1—H1A⋯O4ⁱⁱ	0.89 (1)	2.02 (1)	2.880 (2)	162 (2)
N1—H1B⋯O2ⁱⁱⁱ	0.91 (1)	2.11 (2)	2.967 (3)	157 (2)
N9—H9⋯O3^iv	0.91 (1)	1.97 (1)	2.858 (3)	167 (3)
N9—H9⋯O4^iv	0.91 (1)	2.25 (2)	2.930 (3)	131 (3)

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

Table 2. Intermolecular π–π stacking interactions in the title compound (Å).

centroid	centroid	distance	Symmetry-code
C1—C6	C1—C6	3.711 (1)	(i)
C1—C6	N9—C14	3.676 (2)	(ii)
N9—C14	N9—C14	3.701 (2)	(iii)

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(i) −x + 1, −y, −z, (ii) x, −y + Inline graphic , z − ; (iii) −x, −y, −z + 1

Acknowledgments

Financial support of this work by the Secretaría de Educación Pública (PROMEP-UAS, PTC-035), the Universidad Autónoma de Sinaloa (PROFAPI 2011/048) and CONACyT (grant No. 1564732) is gratefully acknowledged. Thanks are given to the Consejo Superior de Investigaciones Cientificas (CSIC) of Spain for the award of a licence for the use of the Cambridge Structural Database (CSD).

supplementary crystallographic information

Comment

The identification of supramolecular synthons between common functional groups is the first step towards crystal engineering. Specific recognition of the carboxylic acid group and pyridine (acid-pyridine synthon) (Aakeröy & Salmon, 2005; Almarsson & Zaworotko, 2004), or their analogs with proton transfer (Mohamed et al., 2009; Sarma et al., 2009), has been well studied. Both carboxylic acid and pyridine are popular substrates in supramolecular synthesis and herein we report the molecular and crystal structure of 3-aminopyridin-1-ium 3-carboxybenzoate.

The asymmetric unit consists of one 3-aminopyridin-1-ium cation (3AP⁺) and one 3-carboxybenzoate anion (3CB^-), shown in Figure 1. The geometry of intermolecular interactions are given in Table 1. The 3CB^- anion is almost planar with the carboxyl and carboxylate groups forming dihedral angles of 1.9 (4)° and 13.6 (4)°, respectively. A typical pyridinium-carboxylate R²₂(7) synthon is not observed in this organic salt as the pyridinium N9-H9 group forms a three-center interaction with the carboxylate O3 and O4 atoms acting as acceptors (Table 1). Two 3CB^-anions are connected via a short O-H···O hydrogen bonds and the pairs of hydrogen bonded anions are bridged by the primary amino group forming two N-H···O hydrogen bonds. These three interactions generate R⁶₆(18) ring motif and a two-dimensional assembly parallel to (-1 0 2). Adjacent assemblies are connected by hydrogen bonds between the pyridinium N-H groups and the carboxylate groups into a three dimensional framework. This framework consists of stacks of alternating pairs of anions and cations exhibiting π-π stacking interactions with centroid-centroid distances in the range 3.676 (2)-3.711 (1) Å (Table 2). The π-π stacks are extending along [1 1 0] and [-1 1 0].

Experimental

3-Aminopyridine (0.531 mmol), benzene-1,3-dicarboxylic acid (0.531 mmol) and CH₃OH (8 ml) were mixed and the resulting solution allowed to stand at room temperature. After two weeks, colorless crystals of the title compound were obtained (m.p. 498 K).