2-Amino-5-methyl­pyridinium 2-hy­droxy­benzoate

Ching Kheng Quah; Madhukar Hemamalini; Hoong-Kun Fun

doi:10.1107/S1600536810030928

. 2010 Aug 11;66(Pt 9):o2255–o2256. doi: 10.1107/S1600536810030928

2-Amino-5-methylpyridinium 2-hydroxybenzoate

Ching Kheng Quah ^a,^‡, Madhukar Hemamalini ^a, Hoong-Kun Fun ^a,^*,^§

PMCID: PMC3008107 PMID: 21588618

Abstract

In the title compound, C₆H₉N₂ ⁺·C₇H₅O₃ ⁻, the protonated 2-amino-5-methylpyridinium cation and the 2-hydroxybenzoate anion are both essentially planar, with maximum deviations of 0.026 (2) and 0.034 (1) Å, respectively. The anion is stabilized by an intramolecular O—H⋯O hydrogen bond, which forms an S(6) ring motif. In the solid state, the anions are linked to the cations via pairs of intermolecular N—H⋯O hydrogen bonds forming R ₂ ²(8) ring motifs. The crystal structure is further stabilized by N—H⋯O and C—H⋯O interactions which link the molecules into chains along [010]. A π–π stacking interaction [centroid–centroid-distance = 3.740 (2) Å] is also observed.

Related literature

For background to and the applications of carboxylic acids, see: Miller & Orgel (1974 ▶); Kvenvolden et al. (1971 ▶); Desiraju (1989 ▶); MacDonald & Whitesides (1994 ▶). For applications of salicylic acid, see: Singh & Vijayan (1974 ▶); Patel et al. (1988 ▶). For related structures, see: Quah et al. (2008 ▶; 2010a ▶,b ▶). For bond-length data, see: Allen et al. (1987 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₆H₉N₂ ⁺·C₇H₅O₃ ⁻
M _r = 246.26
Monoclinic,
a = 13.211 (7) Å
b = 7.170 (4) Å
c = 14.324 (7) Å
β = 104.668 (11)°
V = 1312.6 (12) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 297 K
0.42 × 0.19 × 0.10 mm

Data collection

Bruker SMART APEXII DUO CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.963, T _max = 0.991
14312 measured reflections
3797 independent reflections
2233 reflections with I > 2σ(I)
R _int = 0.028

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.134
S = 1.01
3797 reflections
219 parameters
All H-atom parameters refined
Δρ_max = 0.14 e Å⁻³
Δρ_min = −0.15 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); 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/S1600536810030928/bt5314sup1.cif

e-66-o2255-sup1.cif^{(17.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810030928/bt5314Isup2.hkl

e-66-o2255-Isup2.hkl^{(186.2KB, 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⋯O3	1.03 (2)	1.65 (2)	2.678 (2)	174.6 (13)
N2—H1N2⋯O2ⁱ	0.884 (18)	1.987 (17)	2.852 (2)	165.4 (14)
N2—H2N2⋯O2	0.97 (2)	1.90 (2)	2.872 (2)	179 (2)
O1—H1O1⋯O3	1.03 (2)	1.55 (2)	2.515 (2)	155 (2)
C5—H5A⋯O1ⁱⁱ	0.961 (14)	2.598 (14)	3.518 (3)	160.2 (10)

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

Acknowledgments

The authors thank Universiti Sains Malaysia (USM) for the Research University Golden Goose Grant (1001/PFIZIK/811012). CKQ also thanks USM for the award of USM fellowship and HM also thanks USM for the award of post doctoral fellowship.

supplementary crystallographic information

Comment

Hydrogen bonding has been established as the most effective tool for constructing sophisticated assemblies because of its strength and directionality. Carboxylic acids are believed to have existed in the prebiotic earth (Miller & Orgel, 1974; Kvenvolden et al., 1971) and they exhibit characteristic intermolecular interactions and aggregation patterns. Also carboxyl groups have been used as primary building blocks in the design of crystal structures (Desiraju, 1989; MacDonald & Whitesides, 1994). Salicylic acid, a well known analgesic, and its complexes with a few drug molecules such as antipyrine (Singh & Vijayan, 1974) and sulfadimidine (Patel et al., 1988) were already reported in the literature. The present study is aimed at investigating the supramolecular interactions of the title compound, (I).

The asymmetric unit of title compound (Fig. 1), contains a protonated 2-amino-5-methylpyridinium cation and a 2-hydroxybenzoate anion. In the 2-amino-5-methylpyridinium cation, a wide angle [122.26 (13)°] is subtended at the protonated N1 atom. The 2-amino-5-methylpyridinium cation and 2-hydroxybenzoate anion are essentially planar, with a maximum deviation of 0.026 (2) Å for atom C6 and 0.034 (1) Å for atom O3, respectively. The diheral angle between these two planes is 4.78 (5)°, indicating they are nearly parallel to each other. The anion is stabilized by an intramolecular O1–H1O1···O3 hydrogen bond, which forms an S(6) ring motif (Bernstein et al., 1995).

In the solid state (Fig. 2), the anions are linked to the cations via intermolecular N1–H1N1···O3 and N2–H2N2..O2 hydrogen bonds forming R₂²(8) ring motifs. The crystal structure is further stabilized by N2–H1N2···O2 and C5–H5A···O1 interactions. The molecules are linked by these interactions into chains along [010]. π–π stacking interactions with short intermolecular distance [3.740 (2) Å] between symmetry-related N1/C1—C5 (centroid Cg1) and C7—C12 (centroid Cg2) [symmetry code: x, 1 + y, z] are also observed.

Experimental

A hot methanol solution (20 ml) of 2-amino-5-methylpyridine (54 mg, Aldrich) and salicylic acid (34.5 mg, Merck) was mixed and warmed over a magnetic stirrer hotplate 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.