2,3-Diamino­pyridinium benzoate

Kasthuri Balasubramani; Hoong-Kun Fun

doi:10.1107/S1600536809021011

. 2009 Jun 6;65(Pt 7):o1519. doi: 10.1107/S1600536809021011

2,3-Diaminopyridinium benzoate

Kasthuri Balasubramani ^a, Hoong-Kun Fun ^a,^*,^‡

PMCID: PMC2969407 PMID: 21582810

Abstract

In the title compound, C₅H₈N₃ ⁺·C₇H₅O₂ ⁻, the pyridine N atom is protonated. The carboxylate group of the benzoate anion is twisted away from the attached ring by 10.91 (9)°. In the crystal structure, N—H⋯O hydrogen bonds between 2,3-diaminopyridinium cations and benzoate anions, and π–π interactions between the pyridinium rings [centroid–centroid distance = 3.6467 (9) Å] form a two-dimensional network parallel to (001). In the network, N—H⋯O hydrogen bonds form R ₂ ²(8) and R ₂ ¹(7) ring motifs.

Related literature

For general background to pyridine derivatives, see: Pozharski et al. (1997 ▶); Katritzky et al. (1996 ▶). For bond-length data, see: Allen et al. (1987 ▶). For details of hydrogen bonding, see: Jeffrey & Saenger (1991 ▶); Jeffrey (1997 ▶); Scheiner (1997 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₅H₈N₃ ⁺·C₇H₅O₂ ⁻
M _r = 231.25
Orthorhombic,
a = 10.1498 (3) Å
b = 11.0656 (3) Å
c = 20.7368 (7) Å
V = 2329.03 (12) Å³
Z = 8
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 K
0.43 × 0.40 × 0.03 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.935, T _max = 0.998
27109 measured reflections
3443 independent reflections
2559 reflections with I > 2σ(I)
R _int = 0.070

Refinement

R[F ² > 2σ(F ²)] = 0.065
wR(F ²) = 0.124
S = 1.09
3443 reflections
206 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); 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 and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809021011/ci2821sup1.cif

e-65-o1519-sup1.cif^{(17KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809021011/ci2821Isup2.hkl

e-65-o1519-Isup2.hkl^{(165.5KB, 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—H1N1⋯O2	0.96 (2)	1.77 (2)	2.7218 (18)	176 (2)
N2—H1N2⋯O1	0.90 (2)	1.94 (2)	2.8377 (18)	173 (2)
N2—H2N2⋯O2ⁱ	0.88 (2)	2.01 (2)	2.8873 (17)	170 (2)
N3—H1N3⋯O2ⁱ	0.91 (2)	2.02 (2)	2.9206 (19)	173 (2)
N3—H2N3⋯O1ⁱⁱ	0.95 (2)	2.00 (2)	2.9382 (19)	170 (2)

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

Acknowledgments

HKF and KB thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312. KB thanks Universiti Sains Malaysia for a post–doctoral research fellowship. HKF also thanks Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012.

supplementary crystallographic information

Comment

Pyridine and its derivatives play an important role in heterocyclic chemistry (Pozharski et al., 1997; Katritzky et al., 1996). Pyridine and its substituted derivatives are often involved in hydrogen-bond interactions (Jeffrey & Saenger, 1991; Jeffrey, 1997; Scheiner, 1997). Since our aim is to study some interesting hydrogen-bonding interactions, the crystal structure of the title compound is presented here.

The asymmetric unit (Fig 1), contains a protonated 2,3-diaminopyridinium cation and a benzoate anion. The bond lengths (Allen et al.,1987) and angles are normal. In the 2,3-diaminopyridinium cation, the protonated N1 atom has lead to a slight increase in C8—N1—C12 angle to 123.30 (14)°. Moreover, the carboxylate group is twisted slightly out of the attached ring; the dihedral angle between C1—C6 and O1/O2/C7/C6 planes is 10.91 (9)°. The 2,3-diaminopyridinium cation is planar, with a maximum deviation of 0.0089 (17) Å for atom C9.

In the crystal packing, the protonated N1 atom and the 2-amino group (N2) is hydrogen-bonded to the carboxylate oxygen atoms (O1 and O2) via a pair of N—H···O hydrogen bonds forming an R₂²(8) ring motif (Bernstein et al., 1995). The two amino groups (N2 and N3) are involved in N—H···O hydrogen bonding interactions to form an R¹₂(7) ring motif. The cationic and anionic units are linked through N—H···O hydrogen bonds (Table 1 and Fig 2) to form a two-dimensional network parallel to the (001) plane. The crystal structure is further stabilized by π-π stacking interactions between the pyridinium rings of the cations at (x, y, z) and (-x, 1-y, 1-z), with a centroid to centroid distance of 3.6467 (9) Å.

Experimental

Hot methanol solutions (20 ml) of 2,3-diaminopyridine (27 mg, Aldrich) and benzoic acid (31 mg, Merck) were mixed and warmed over a heating magnetic stirrer for 5 minutes. The resulting solution was allowed to cool slowly at room temperature. Crystals of the title compound appeared from the mother liquor after a few days.