2-Amino-5-methyl­pyridinium 2-carb­oxy­acetate

Madhukar Hemamalini; Hoong-Kun Fun

doi:10.1107/S1600536810019239

. 2010 May 29;66(Pt 6):o1480–o1481. doi: 10.1107/S1600536810019239

2-Amino-5-methylpyridinium 2-carboxyacetate

Madhukar Hemamalini ^a, Hoong-Kun Fun ^a,^*,^‡

PMCID: PMC2979470 PMID: 21579546

Abstract

In the title molecular salt, C₆H₉N₂ ⁺·C₃H₃O₄ ⁻, the cation is essentially planar, with a maximum deviation of 0.010 (3) Å. In the anion, an intramolecular O—H⋯O hydrogen bond generates an S(6) ring and results in a folded conformation. In the crystal, the protonated NH group and the 2-amino group of the cation are hydrogen bonded to the carboxylate O atoms of the anion via a pair of N—H⋯O hydrogen bonds, forming an R ² ₂(8) ring motif. Weak intermolecular C—H⋯O interactions help to further stabilize the crystal structure.

Related literature

For background to the chemistry of substituted pyridines, see: Pozharski et al. (1997 ▶); Katritzky et al. (1996 ▶). For related structures, see: Nahringbauer & Kvick (1977 ▶); Feng et al. (2005 ▶); Xuan et al. (2003 ▶); Jin et al. (2005 ▶); Hemamalini & Fun (2010a ▶,b ▶,c ▶). For details of hydrogen bonding, see: Jeffrey & Saenger (1991 ▶); Jeffrey (1997 ▶); Scheiner (1997 ▶). For the conformation of the malonate ion, see: Djinović et al. (1990 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For bond-length data, see: Allen et al. (1987 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₆H₉N₂ ⁺·C₃H₃O₄ ⁻
M _r = 212.21
Monoclinic,
a = 3.8082 (13) Å
b = 16.963 (5) Å
c = 15.372 (5) Å
β = 95.436 (9)°
V = 988.6 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 100 K
0.22 × 0.21 × 0.13 mm

Data collection

Bruker APEXII DUO CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.975, T _max = 0.986
8134 measured reflections
2210 independent reflections
1647 reflections with I > 2σ(I)
R _int = 0.049

Refinement

R[F ² > 2σ(F ²)] = 0.058
wR(F ²) = 0.185
S = 1.11
2210 reflections
180 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.41 e Å⁻³
Δρ_min = −0.35 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT (Bruker, 2009 ▶); 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/S1600536810019239/hb5460sup1.cif

e-66-o1480-sup1.cif^{(15.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810019239/hb5460Isup2.hkl

e-66-o1480-Isup2.hkl^{(106.4KB, 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
O3—H1O3⋯O1	1.00	1.53	2.475 (3)	157
N1—H1N1⋯O2ⁱ	1.02 (3)	1.65 (3)	2.652 (3)	170 (3)
N2—H1N2⋯O4ⁱⁱ	0.90 (3)	2.00 (3)	2.886 (3)	171 (3)
N2—H2N2⋯O1ⁱ	0.98 (3)	1.95 (3)	2.924 (3)	177 (3)
C2—H2A⋯O3ⁱⁱ	0.93 (3)	2.58 (3)	3.470 (3)	159 (2)
C8—H8A⋯O2ⁱⁱⁱ	0.95 (3)	2.41 (3)	3.304 (3)	158 (3)

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

Acknowledgments

MH and HKF thank the Malaysian Government and Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012. MH also thanks USM for a post-doctoral research fellowship.

supplementary crystallographic information

Comment

Pyridine and its derivatives play an important role in heterocyclic chemistry (Pozharski et al., 1997; Katritzky et al., 1996). They are often involved in hydrogen-bond interactions (Jeffrey & Saenger, 1991; Jeffrey, 1997; Scheiner, 1997). The crystal structures of 2-amino-5-methylpyridine (Nahringbauer & Kvick, 1977), 2-amino-5-methylpyridinium phosphate (Feng et al., 2005), 2-amino-5-methylpyridinium 3-(4- hydroxy-3-methoxyphenyl)-2-propenoate monohydrate (Xuan et al., 2003) and 2-amino-5-methylpyridinium (2-amino-5- methylpyridine)trichlorozincate(II) (Jin et al., 2005) have been reported in the literature. We have recently reported the crystal structures of 2-amino-5-methylpyridinium 3-aminobenzoate (Hemamalini & Fun, 2010a), 2-amino-5-methylpyridinium 4-nitrobenzoate (Hemamalini & Fun, 2010b) and 2-amino-5-methylpyridinium nicotinate (Hemamalini & Fun, 2010c) from our laboratory. In order to study some interesting hydrogen bonding interactions, the synthesis and structure of the title salt is presented here.

The asymmetric unit (Fig. 1) contains one 2-amino-5-methylpyridinium cation and one hydrogen malonate anion. The proton transfer from the one of the carboxyl group oxygen atom (O2) to atom N1 of 2-amino-5-methylpyridine resulted in the widening of C1—N1—C5 angle of the pyridinium ring to 123.3 (2)°, compared to the corresponding angle of 117.4 (3)° in neutral 2-amino-5-methylpyridine (Nahringbauer & Kvick, 1977). The 2-amino-5-methylpyridinium cation is essentially planar, with a maximum deviation of 0.010 (3) Å for atom C4. The bond lengths and angles are normal (Allen et al., 1987).

In the crystal packing (Fig. 2), the protonated N1 atom and the 2-amino group (N2) is hydrogen-bonded to the carboxylate oxygen atoms (O6 and O7) via a pair of intermolecular N1—H1N1···O2 and N2—H2N2···O1 hydrogen bonds forming a ring motif R²₂(8) (Bernstein et al., 1995). Atom O3 of the carboxyl group of the hydrogen malonate anions forms an intramolecular O3—H1O3···O1 hydrogen bond with the O atom of the carboxylate group (O1) [with graph-set notation S(6)], leading to a folded conformation. A similar intramolecular hydrogen bond has been observed in the crystal structures of benzylammonium hydrogen malonate and 4-picolinium hydrogen malonate (Djinović et al., 1990). The crystal structure is further stabilized by weak C2—H2A···O3 and C8—H8A···O2 (Table 1) hydrogen bonds.

Experimental

A hot methanol solution (20 ml) of 2-amino-5-methylpyridine (27 mg) and malonic acid (52 mg) 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 colourless blocks of (I) appeared after a few days.