organic compounds
2-Amino-5-methylpyridinium 4-nitrobenzoate
aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
*Correspondence e-mail: hkfun@usm.my
In the title compound, C6H9N2+·C7H4NO4−, the nitro group of the 4-nitrobenzoate anion is twisted by 6.2 (2)° from the attached ring. In the the cations and anions are linked via strong N—H⋯O and weak C—H⋯O hydrogen bonds, forming a three-dimensional network.
Related literature
For background to the chemistry of substituted pyridines, see: Pozharski et al. (1997); Katritzky et al. (1996); Hemamalini & Fun (2010). For details of hydrogen bonding, see: Jeffrey & Saenger (1991); Jeffrey (1997); Scheiner (1997). 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
|
Refinement
|
Data collection: APEX2 (Bruker, 2009); cell 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).
Supporting information
10.1107/S1600536810005301/sj2727sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536810005301/sj2727Isup2.hkl
A hot methanol solution (20 ml) of 2-amino-5-methylpyridine (27 mg, Aldrich) and 4-nitrobenzoic acid (42 mg, Merck) 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 crystals of the title compound appeared after a few days.
The methyl H atoms were positioned geometrically and were refined using a riding model, with Uiso(H) = 1.5Ueq(C). A rotating group model was used for the methyl group. The remaining H atoms were located in a difference map and refined freely [N–H = 0.89 (4)–0.97 (4)Å and C–H = 0.89 (4)–0.98 (4)Å]. In the absence of significant
effects, 1641 Friedel pairs were merged.Data collection: APEX2 (Bruker, 2009); cell
SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).Fig. 1. The asymmetric unit of the title compound. Displacement ellipsoids are drawn at the 50% probability level. | |
Fig. 2. The crystal packing of the title compound, showing hydrogen-bonded (dashed lines) networks. |
C6H9N2+·C7H4NO4− | F(000) = 288 |
Mr = 275.26 | Dx = 1.441 Mg m−3 |
Monoclinic, Pc | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P -2yc | Cell parameters from 1854 reflections |
a = 13.684 (12) Å | θ = 3.2–28.2° |
b = 4.025 (4) Å | µ = 0.11 mm−1 |
c = 12.706 (11) Å | T = 100 K |
β = 114.94 (2)° | Block, colourless |
V = 634.5 (10) Å3 | 0.36 × 0.18 × 0.08 mm |
Z = 2 |
Bruker APEX DUO CCD area-detector diffractometer | 1854 independent reflections |
Radiation source: fine-focus sealed tube | 1283 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.042 |
ϕ and ω scans | θmax = 30.0°, θmin = 1.6° |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | h = −18→19 |
Tmin = 0.961, Tmax = 0.991 | k = −5→5 |
7053 measured reflections | l = −17→17 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.045 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.116 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.06 | w = 1/[σ2(Fo2) + (0.0604P)2] where P = (Fo2 + 2Fc2)/3 |
1854 reflections | (Δ/σ)max < 0.001 |
222 parameters | Δρmax = 0.19 e Å−3 |
2 restraints | Δρmin = −0.20 e Å−3 |
C6H9N2+·C7H4NO4− | V = 634.5 (10) Å3 |
Mr = 275.26 | Z = 2 |
Monoclinic, Pc | Mo Kα radiation |
a = 13.684 (12) Å | µ = 0.11 mm−1 |
b = 4.025 (4) Å | T = 100 K |
c = 12.706 (11) Å | 0.36 × 0.18 × 0.08 mm |
β = 114.94 (2)° |
Bruker APEX DUO CCD area-detector diffractometer | 1854 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | 1283 reflections with I > 2σ(I) |
Tmin = 0.961, Tmax = 0.991 | Rint = 0.042 |
7053 measured reflections |
R[F2 > 2σ(F2)] = 0.045 | 2 restraints |
wR(F2) = 0.116 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.06 | Δρmax = 0.19 e Å−3 |
1854 reflections | Δρmin = −0.20 e Å−3 |
222 parameters |
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) k. |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
N1 | 0.83203 (19) | 0.0861 (6) | 0.16111 (18) | 0.0407 (6) | |
N2 | 0.7398 (2) | 0.0221 (8) | −0.0369 (2) | 0.0498 (7) | |
C1 | 0.8230 (2) | 0.1476 (7) | 0.0532 (2) | 0.0399 (7) | |
C2 | 0.9053 (3) | 0.3372 (8) | 0.0431 (3) | 0.0489 (8) | |
C3 | 0.9897 (3) | 0.4449 (9) | 0.1392 (3) | 0.0508 (8) | |
C4 | 0.9979 (3) | 0.3777 (7) | 0.2514 (3) | 0.0459 (7) | |
C5 | 0.9169 (2) | 0.1971 (8) | 0.2569 (3) | 0.0429 (7) | |
C6 | 1.0921 (3) | 0.4935 (10) | 0.3582 (3) | 0.0653 (9) | |
H6A | 1.0781 | 0.4540 | 0.4251 | 0.098* | |
H6B | 1.1030 | 0.7269 | 0.3519 | 0.098* | |
H6C | 1.1555 | 0.3739 | 0.3662 | 0.098* | |
O1 | 0.1957 (2) | −0.0891 (11) | 0.1134 (2) | 0.0995 (12) | |
O2 | 0.2751 (3) | −0.0198 (10) | 0.2954 (3) | 0.0953 (11) | |
O3 | 0.61995 (19) | 0.6210 (7) | 0.04604 (18) | 0.0613 (7) | |
O4 | 0.70099 (15) | 0.7415 (6) | 0.23282 (17) | 0.0504 (5) | |
N3 | 0.2718 (2) | 0.0063 (7) | 0.1991 (2) | 0.0548 (7) | |
C7 | 0.5306 (2) | 0.4378 (8) | 0.2704 (2) | 0.0401 (6) | |
C8 | 0.4456 (2) | 0.2895 (8) | 0.2828 (2) | 0.0428 (6) | |
C9 | 0.3641 (2) | 0.1565 (7) | 0.1870 (2) | 0.0400 (6) | |
C10 | 0.3648 (3) | 0.1575 (8) | 0.0790 (3) | 0.0470 (7) | |
C11 | 0.4522 (2) | 0.3019 (8) | 0.0683 (2) | 0.0443 (7) | |
C12 | 0.5345 (2) | 0.4473 (7) | 0.1622 (2) | 0.0339 (5) | |
C13 | 0.6260 (2) | 0.6165 (7) | 0.1462 (2) | 0.0401 (7) | |
H2A | 0.896 (2) | 0.396 (9) | −0.035 (3) | 0.048 (8)* | |
H3A | 1.042 (3) | 0.577 (9) | 0.131 (3) | 0.059 (10)* | |
H5A | 0.915 (3) | 0.145 (9) | 0.328 (3) | 0.055 (9)* | |
H7A | 0.585 (2) | 0.545 (7) | 0.333 (2) | 0.034 (7)* | |
H9A | 0.442 (3) | 0.273 (8) | 0.355 (4) | 0.061 (10)* | |
H10A | 0.308 (3) | 0.083 (10) | 0.017 (3) | 0.065 (11)* | |
H11A | 0.459 (3) | 0.323 (10) | −0.006 (4) | 0.070 (11)* | |
H1N1 | 0.775 (4) | −0.035 (9) | 0.171 (3) | 0.059 (10)* | |
H1N2 | 0.728 (3) | 0.097 (9) | −0.107 (3) | 0.052 (9)* | |
H2N2 | 0.691 (3) | −0.087 (9) | −0.019 (3) | 0.055 (10)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0419 (14) | 0.0442 (13) | 0.0410 (12) | 0.0003 (11) | 0.0224 (11) | 0.0046 (11) |
N2 | 0.0518 (16) | 0.0608 (17) | 0.0392 (13) | 0.0021 (13) | 0.0217 (12) | 0.0057 (12) |
C1 | 0.0431 (16) | 0.0395 (16) | 0.0406 (14) | 0.0106 (12) | 0.0211 (13) | 0.0076 (12) |
C2 | 0.061 (2) | 0.0446 (17) | 0.0533 (17) | 0.0047 (14) | 0.0356 (16) | 0.0118 (14) |
C3 | 0.0485 (19) | 0.0460 (18) | 0.064 (2) | −0.0025 (15) | 0.0299 (16) | 0.0072 (15) |
C4 | 0.0455 (17) | 0.0389 (15) | 0.0514 (16) | 0.0041 (13) | 0.0186 (14) | 0.0031 (14) |
C5 | 0.0444 (16) | 0.0457 (16) | 0.0393 (15) | 0.0034 (13) | 0.0183 (13) | 0.0043 (13) |
C6 | 0.052 (2) | 0.064 (2) | 0.066 (2) | −0.0083 (17) | 0.0123 (16) | 0.0025 (17) |
O1 | 0.069 (2) | 0.162 (3) | 0.0674 (18) | −0.061 (2) | 0.0293 (16) | −0.0244 (19) |
O2 | 0.090 (2) | 0.152 (3) | 0.0620 (17) | −0.046 (2) | 0.0490 (17) | −0.0059 (18) |
O3 | 0.0633 (15) | 0.0915 (18) | 0.0378 (11) | −0.0184 (13) | 0.0299 (11) | −0.0033 (12) |
O4 | 0.0455 (12) | 0.0696 (14) | 0.0406 (11) | −0.0138 (11) | 0.0224 (9) | −0.0070 (10) |
N3 | 0.0509 (16) | 0.0659 (18) | 0.0539 (16) | −0.0126 (14) | 0.0283 (13) | −0.0038 (14) |
C7 | 0.0454 (16) | 0.0462 (16) | 0.0284 (12) | −0.0042 (13) | 0.0151 (12) | −0.0026 (11) |
C8 | 0.0498 (17) | 0.0510 (18) | 0.0330 (13) | −0.0057 (14) | 0.0227 (12) | −0.0005 (12) |
C9 | 0.0410 (16) | 0.0405 (16) | 0.0424 (15) | 0.0001 (11) | 0.0216 (13) | 0.0031 (12) |
C10 | 0.0476 (18) | 0.0576 (19) | 0.0325 (14) | −0.0095 (15) | 0.0135 (13) | −0.0051 (13) |
C11 | 0.0524 (18) | 0.0542 (19) | 0.0305 (13) | −0.0037 (14) | 0.0216 (13) | −0.0002 (12) |
C12 | 0.0377 (14) | 0.0360 (14) | 0.0297 (11) | 0.0035 (10) | 0.0160 (10) | 0.0013 (10) |
C13 | 0.0445 (17) | 0.0470 (16) | 0.0330 (14) | −0.0004 (13) | 0.0203 (12) | 0.0017 (11) |
N1—C1 | 1.347 (3) | O1—N3 | 1.208 (4) |
N1—C5 | 1.355 (4) | O2—N3 | 1.210 (4) |
N1—H1N1 | 0.97 (4) | O3—C13 | 1.241 (3) |
N2—C1 | 1.328 (4) | O4—C13 | 1.251 (3) |
N2—H1N2 | 0.89 (4) | N3—C9 | 1.466 (4) |
N2—H2N2 | 0.90 (4) | C7—C8 | 1.374 (4) |
C1—C2 | 1.410 (4) | C7—C12 | 1.399 (4) |
C2—C3 | 1.350 (5) | C7—H7A | 0.94 (3) |
C2—H2A | 0.97 (3) | C8—C9 | 1.366 (4) |
C3—C4 | 1.408 (5) | C8—H9A | 0.94 (4) |
C3—H3A | 0.94 (4) | C9—C10 | 1.375 (4) |
C4—C5 | 1.352 (5) | C10—C11 | 1.387 (5) |
C4—C6 | 1.499 (5) | C10—H10A | 0.89 (4) |
C5—H5A | 0.93 (4) | C11—C12 | 1.379 (4) |
C6—H6A | 0.9600 | C11—H11A | 0.98 (4) |
C6—H6B | 0.9600 | C12—C13 | 1.512 (4) |
C6—H6C | 0.9600 | ||
C1—N1—C5 | 122.0 (3) | H6B—C6—H6C | 109.5 |
C1—N1—H1N1 | 119 (2) | O1—N3—O2 | 122.2 (3) |
C5—N1—H1N1 | 119 (2) | O1—N3—C9 | 119.3 (3) |
C1—N2—H1N2 | 117 (2) | O2—N3—C9 | 118.4 (3) |
C1—N2—H2N2 | 115 (2) | C8—C7—C12 | 120.6 (3) |
H1N2—N2—H2N2 | 125 (3) | C8—C7—H7A | 121.1 (18) |
N2—C1—N1 | 119.0 (3) | C12—C7—H7A | 118.2 (18) |
N2—C1—C2 | 123.7 (3) | C9—C8—C7 | 118.7 (3) |
N1—C1—C2 | 117.2 (3) | C9—C8—H9A | 118 (2) |
C3—C2—C1 | 120.2 (3) | C7—C8—H9A | 123 (2) |
C3—C2—H2A | 122.6 (19) | C8—C9—C10 | 122.8 (3) |
C1—C2—H2A | 117.1 (19) | C8—C9—N3 | 118.9 (2) |
C2—C3—C4 | 121.7 (3) | C10—C9—N3 | 118.3 (3) |
C2—C3—H3A | 119 (2) | C9—C10—C11 | 117.9 (3) |
C4—C3—H3A | 119 (2) | C9—C10—H10A | 120 (2) |
C5—C4—C3 | 116.0 (3) | C11—C10—H10A | 122 (2) |
C5—C4—C6 | 122.1 (3) | C12—C11—C10 | 121.1 (3) |
C3—C4—C6 | 121.8 (3) | C12—C11—H11A | 115 (2) |
C4—C5—N1 | 122.8 (3) | C10—C11—H11A | 124 (2) |
C4—C5—H5A | 122 (2) | C11—C12—C7 | 118.9 (3) |
N1—C5—H5A | 116 (2) | C11—C12—C13 | 119.7 (2) |
C4—C6—H6A | 109.5 | C7—C12—C13 | 121.4 (2) |
C4—C6—H6B | 109.5 | O3—C13—O4 | 124.8 (3) |
H6A—C6—H6B | 109.5 | O3—C13—C12 | 116.3 (2) |
C4—C6—H6C | 109.5 | O4—C13—C12 | 118.8 (2) |
H6A—C6—H6C | 109.5 | ||
C5—N1—C1—N2 | 177.7 (3) | O2—N3—C9—C8 | −6.1 (5) |
C5—N1—C1—C2 | −0.7 (4) | O1—N3—C9—C10 | −5.5 (5) |
N2—C1—C2—C3 | −177.3 (3) | O2—N3—C9—C10 | 173.9 (3) |
N1—C1—C2—C3 | 1.1 (4) | C8—C9—C10—C11 | −0.3 (5) |
C1—C2—C3—C4 | −1.0 (5) | N3—C9—C10—C11 | 179.6 (3) |
C2—C3—C4—C5 | 0.6 (5) | C9—C10—C11—C12 | −1.6 (5) |
C2—C3—C4—C6 | 179.3 (3) | C10—C11—C12—C7 | 2.1 (4) |
C3—C4—C5—N1 | −0.2 (5) | C10—C11—C12—C13 | −177.2 (3) |
C6—C4—C5—N1 | −178.9 (3) | C8—C7—C12—C11 | −0.8 (4) |
C1—N1—C5—C4 | 0.3 (4) | C8—C7—C12—C13 | 178.5 (3) |
C12—C7—C8—C9 | −1.1 (4) | C11—C12—C13—O3 | 1.7 (4) |
C7—C8—C9—C10 | 1.6 (5) | C7—C12—C13—O3 | −177.6 (3) |
C7—C8—C9—N3 | −178.3 (3) | C11—C12—C13—O4 | −178.7 (3) |
O1—N3—C9—C8 | 174.4 (4) | C7—C12—C13—O4 | 2.1 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1N1···O3i | 0.97 (5) | 2.47 (4) | 3.238 (5) | 136 (3) |
N1—H1N1···O4i | 0.97 (5) | 1.77 (5) | 2.711 (4) | 163 (3) |
N2—H1N2···O4ii | 0.89 (4) | 2.02 (4) | 2.905 (4) | 179 (5) |
N2—H2N2···O3i | 0.91 (4) | 1.92 (4) | 2.804 (5) | 165 (4) |
C3—H3A···O1iii | 0.93 (4) | 2.58 (4) | 3.514 (6) | 176 (3) |
Symmetry codes: (i) x, y−1, z; (ii) x, −y+1, z−1/2; (iii) x+1, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | C6H9N2+·C7H4NO4− |
Mr | 275.26 |
Crystal system, space group | Monoclinic, Pc |
Temperature (K) | 100 |
a, b, c (Å) | 13.684 (12), 4.025 (4), 12.706 (11) |
β (°) | 114.94 (2) |
V (Å3) | 634.5 (10) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.11 |
Crystal size (mm) | 0.36 × 0.18 × 0.08 |
Data collection | |
Diffractometer | Bruker APEX DUO CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2009) |
Tmin, Tmax | 0.961, 0.991 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 7053, 1854, 1283 |
Rint | 0.042 |
(sin θ/λ)max (Å−1) | 0.703 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.116, 1.06 |
No. of reflections | 1854 |
No. of parameters | 222 |
No. of restraints | 2 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.19, −0.20 |
Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1N1···O3i | 0.97 (5) | 2.47 (4) | 3.238 (5) | 136 (3) |
N1—H1N1···O4i | 0.97 (5) | 1.77 (5) | 2.711 (4) | 163 (3) |
N2—H1N2···O4ii | 0.89 (4) | 2.02 (4) | 2.905 (4) | 179 (5) |
N2—H2N2···O3i | 0.91 (4) | 1.92 (4) | 2.804 (5) | 165 (4) |
C3—H3A···O1iii | 0.93 (4) | 2.58 (4) | 3.514 (6) | 176 (3) |
Symmetry codes: (i) x, y−1, z; (ii) x, −y+1, z−1/2; (iii) x+1, y+1, z. |
Footnotes
‡Thomson Reuters ResearcherID: A-3561-2009.
Acknowledgements
MH and HKF thank the Malaysian Government and Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012. MH thanks Universiti Sains Malaysia for a post-doctoral research fellowship.
References
Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19. CrossRef Web of Science Google Scholar
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Cosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105–107. CrossRef CAS Web of Science IUCr Journals Google Scholar
Hemamalini, M. & Fun, H.-K. (2010). Acta Cryst. E66, o335. Web of Science CSD CrossRef IUCr Journals Google Scholar
Jeffrey, G. A. (1997). An Introduction to Hydrogen Bonding. Oxford University Press. Google Scholar
Jeffrey, G. A. & Saenger, W. (1991). Hydrogen Bonding in Biological Structures. Berlin: Springer. Google Scholar
Katritzky, A. R., Rees, C. W. & Scriven, E. F. V. (1996). Comprehensive Heterocyclic Chemistry II. Oxford: Pergamon Press. Google Scholar
Pozharski, A. F., Soldatenkov, A. T. & Katritzky, A. R. (1997). Heterocycles in Life and Society. New York: Wiley. Google Scholar
Scheiner, S. (1997). Hydrogen Bonding. A Theoretical Perspective. Oxford University Press. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Pyridine and its derivatives play important roles 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). We have recently reported the crystal structure of 2-amino-4-methylpyridinium 4-nitrobenzoate (Hemamalini & Fun, 2010). In a continuation of our studies of pyridinium derivatives, the crystal structure of title compound is presented here.
The asymmetric unit of the title compound (Fig 1), contains a protonated 2-amino-5-methylpyridinium cation and a 4-nitrobenzoate anion. In the 4-nitrobenzoate anion, the nitro group is twisted slightly from the ring with the dihedral angle between O1/O2/N3/C9 and C7–C12 planes being 6.2 (2)°. In the 2-amino-5-methylpyridinium cation, a wide angle (122.0 (3)°) is subtended at the protonated N1 atom. The 2-amino-5-methylpyridinium cation is planar, with a maximum deviation of 0.015 (4)Å for atom C2. The bond lengths are normal (Allen et al., 1987).
In the crystal (Fig. 2), the protonated N1 atom and the 2-amino group (N2) are hydrogen-bonded to the carboxylate oxygen atoms (O3 and O4) via a pair of N—H···O hydrogen bonds forming an R22(8) ring motif (Bernstein et al., 1995). Bifurcated hydrogen bonds are observed between the carboxylate oxygen atoms (O3 & O4) and the protonated N atom to form a four-membered R12(4) hydrogen-bonded ring. The crystal structure is further stabilized by weak C—H···O (Table 1) hydrogen bonds to form a three-dimensional network.