organic compounds
2-Amino-5-methylpyridinium 6-oxo-1,6-dihydropyridine-2-carboxylate
aSchool of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
*Correspondence e-mail: arazaki@usm.my
The anion of the title salt, C6H9N2+·C6H4NO3−, undergoes an enol-to-keto during the crystallization. In the the cation and anion are held together by a relatively short N—H⋯O hydrogen bond, and the two anions are further connected to each other by a pair of N—H⋯O hydrogen bonds with an R22(8) ring motif, thus forming a centrosymmetric 2 + 2 aggregate. The aggregates are further linked through weak N—H⋯O and C—H⋯O hydrogen bonds, resulting a three-dimensional network.
Related literature
For details of 2-aminopyridine and its derivatives, see: Banerjee & Murugavel (2004); Bis & Zaworotko (2005); Bis et al. (2006). For details of 6-hydroxypicolinic acid, see: Sun et al. (2004); Soares-Santos et al. (2003). For a related structure, see: Sawada & Ohashi (1998). For hydrogen-bond motifs, see: Bernstein et al. (1995). For bond-length data, see: Allen et al. (1987). For stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986).
Experimental
Crystal data
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Refinement
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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/S1600536812041359/is5197sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812041359/is5197Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812041359/is5197Isup3.cml
Hot methanol solutions (20 ml) of 2-amino5-methylpyridine (54 mg, Aldrich) and 6-Hydroxypicolinic acid (69 mg, Merck) were mixed and warmed over a heating magnetic stirrer hotplate for a few minutes. The resulting solution was allowed to cool slowly at room temperature and crystals of the title compound (I) appeared after a few days.
N-bound H atoms were located in a difference Fourier map and refined freely [refined N—H distances 0.899 (15), 0.954 (16), 0.900 (16) and 0.938 (15) Å]. The remaining H atoms were positioned geometrically (C—H= 0.95–0.98 Å) and were refined using a riding model, with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(methyl C). A rotating group model was used for the methyl group. In the final
four outliers were omitted (-1 3 2, -4 6 5,-1 1 1 and -4 6 4).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 molecular structure of the title compound with atom labels with 50% probability displacement ellipsoids. | |
Fig. 2. The crystal packing of the title compound, viewed down the c axis. |
C6H9N2+·C6H4NO3− | F(000) = 520 |
Mr = 247.25 | Dx = 1.341 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 6176 reflections |
a = 11.7093 (6) Å | θ = 3.6–32.6° |
b = 10.4594 (6) Å | µ = 0.10 mm−1 |
c = 11.4590 (6) Å | T = 100 K |
β = 119.203 (1)° | Block, colourless |
V = 1225.03 (11) Å3 | 0.45 × 0.35 × 0.23 mm |
Z = 4 |
Bruker SMART APEXII DUO CCD area-detector diffractometer | 4430 independent reflections |
Radiation source: fine-focus sealed tube | 3745 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.027 |
ϕ and ω scans | θmax = 32.6°, θmin = 3.6° |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | h = −17→17 |
Tmin = 0.957, Tmax = 0.978 | k = −15→15 |
15984 measured reflections | l = −16→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)] = 0.039 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.116 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0661P)2 + 0.2292P] where P = (Fo2 + 2Fc2)/3 |
4430 reflections | (Δ/σ)max < 0.001 |
180 parameters | Δρmax = 0.43 e Å−3 |
0 restraints | Δρmin = −0.21 e Å−3 |
C6H9N2+·C6H4NO3− | V = 1225.03 (11) Å3 |
Mr = 247.25 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 11.7093 (6) Å | µ = 0.10 mm−1 |
b = 10.4594 (6) Å | T = 100 K |
c = 11.4590 (6) Å | 0.45 × 0.35 × 0.23 mm |
β = 119.203 (1)° |
Bruker SMART APEXII DUO CCD area-detector diffractometer | 4430 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | 3745 reflections with I > 2σ(I) |
Tmin = 0.957, Tmax = 0.978 | Rint = 0.027 |
15984 measured reflections |
R[F2 > 2σ(F2)] = 0.039 | 0 restraints |
wR(F2) = 0.116 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.02 | Δρmax = 0.43 e Å−3 |
4430 reflections | Δρmin = −0.21 e Å−3 |
180 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 e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > σ(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 | ||
O1 | 0.37734 (6) | 0.60282 (6) | 0.39711 (6) | 0.01806 (13) | |
O2 | 0.80810 (7) | 0.48126 (7) | 0.29773 (7) | 0.02633 (15) | |
O3 | 0.79587 (6) | 0.45930 (6) | 0.48584 (7) | 0.02282 (14) | |
N1 | 0.55569 (6) | 0.55843 (7) | 0.37336 (7) | 0.01512 (13) | |
N2 | 0.02845 (7) | 0.72276 (7) | 0.43791 (7) | 0.01818 (14) | |
N3 | 0.14291 (7) | 0.77377 (8) | 0.32695 (8) | 0.02345 (16) | |
C1 | 0.43630 (7) | 0.61584 (7) | 0.33157 (8) | 0.01518 (14) | |
C2 | 0.38707 (8) | 0.68852 (8) | 0.21019 (8) | 0.02096 (16) | |
H2A | 0.3064 | 0.7328 | 0.1776 | 0.025* | |
C3 | 0.45395 (9) | 0.69519 (10) | 0.14089 (9) | 0.02493 (18) | |
H3A | 0.4195 | 0.7439 | 0.0608 | 0.030* | |
C4 | 0.57443 (9) | 0.63000 (9) | 0.18740 (9) | 0.02318 (17) | |
H4A | 0.6203 | 0.6326 | 0.1382 | 0.028* | |
C5 | 0.62317 (8) | 0.56351 (8) | 0.30428 (8) | 0.01706 (15) | |
C6 | 0.75338 (8) | 0.49530 (8) | 0.36664 (9) | 0.01855 (15) | |
C7 | −0.25015 (10) | 0.86990 (10) | 0.46610 (12) | 0.0311 (2) | |
H7A | −0.2490 | 0.7998 | 0.5234 | 0.047* | |
H7B | −0.3361 | 0.8737 | 0.3856 | 0.047* | |
H7C | −0.2328 | 0.9509 | 0.5149 | 0.047* | |
C8 | −0.14653 (8) | 0.84727 (8) | 0.42693 (9) | 0.02107 (16) | |
C9 | −0.12821 (9) | 0.93128 (9) | 0.34046 (10) | 0.02358 (17) | |
H9A | −0.1834 | 1.0039 | 0.3055 | 0.028* | |
C10 | −0.03306 (9) | 0.91053 (9) | 0.30608 (9) | 0.02217 (17) | |
H10A | −0.0219 | 0.9685 | 0.2486 | 0.027* | |
C11 | 0.04861 (7) | 0.80162 (8) | 0.35711 (8) | 0.01760 (15) | |
C12 | −0.06528 (8) | 0.74369 (8) | 0.47303 (8) | 0.01970 (16) | |
H12A | −0.0746 | 0.6849 | 0.5310 | 0.024* | |
H1N1 | 0.5904 (14) | 0.5129 (15) | 0.4496 (14) | 0.033 (3)* | |
H2N3 | 0.1961 (15) | 0.7063 (15) | 0.3644 (15) | 0.037 (4)* | |
H1N3 | 0.1663 (14) | 0.8348 (15) | 0.2824 (14) | 0.034 (3)* | |
H1N2 | 0.0830 (15) | 0.6489 (15) | 0.4686 (16) | 0.040 (4)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0171 (3) | 0.0218 (3) | 0.0192 (3) | 0.0032 (2) | 0.0119 (2) | 0.0018 (2) |
O2 | 0.0276 (3) | 0.0276 (3) | 0.0359 (4) | 0.0033 (2) | 0.0250 (3) | 0.0001 (3) |
O3 | 0.0197 (3) | 0.0248 (3) | 0.0278 (3) | 0.0060 (2) | 0.0146 (2) | 0.0074 (2) |
N1 | 0.0151 (3) | 0.0164 (3) | 0.0162 (3) | 0.0019 (2) | 0.0095 (2) | 0.0018 (2) |
N2 | 0.0169 (3) | 0.0183 (3) | 0.0205 (3) | 0.0015 (2) | 0.0101 (2) | 0.0027 (2) |
N3 | 0.0218 (3) | 0.0263 (4) | 0.0279 (4) | 0.0065 (3) | 0.0166 (3) | 0.0067 (3) |
C1 | 0.0146 (3) | 0.0155 (3) | 0.0166 (3) | 0.0011 (2) | 0.0084 (3) | −0.0002 (2) |
C2 | 0.0188 (3) | 0.0228 (4) | 0.0218 (4) | 0.0046 (3) | 0.0104 (3) | 0.0068 (3) |
C3 | 0.0245 (4) | 0.0297 (4) | 0.0229 (4) | 0.0045 (3) | 0.0134 (3) | 0.0097 (3) |
C4 | 0.0245 (4) | 0.0278 (4) | 0.0234 (4) | 0.0029 (3) | 0.0165 (3) | 0.0062 (3) |
C5 | 0.0178 (3) | 0.0177 (3) | 0.0201 (3) | 0.0008 (2) | 0.0128 (3) | 0.0003 (3) |
C6 | 0.0184 (3) | 0.0156 (3) | 0.0269 (4) | 0.0005 (2) | 0.0152 (3) | 0.0003 (3) |
C7 | 0.0284 (4) | 0.0308 (5) | 0.0453 (6) | −0.0001 (4) | 0.0269 (4) | −0.0044 (4) |
C8 | 0.0190 (3) | 0.0219 (4) | 0.0259 (4) | −0.0008 (3) | 0.0138 (3) | −0.0025 (3) |
C9 | 0.0213 (4) | 0.0218 (4) | 0.0293 (4) | 0.0058 (3) | 0.0137 (3) | 0.0036 (3) |
C10 | 0.0223 (4) | 0.0217 (4) | 0.0246 (4) | 0.0053 (3) | 0.0131 (3) | 0.0063 (3) |
C11 | 0.0160 (3) | 0.0194 (3) | 0.0182 (3) | 0.0009 (2) | 0.0090 (3) | 0.0009 (3) |
C12 | 0.0195 (3) | 0.0210 (4) | 0.0215 (4) | −0.0020 (3) | 0.0122 (3) | −0.0002 (3) |
O1—C1 | 1.2511 (9) | C3—H3A | 0.9500 |
O2—C6 | 1.2447 (9) | C4—C5 | 1.3628 (12) |
O3—C6 | 1.2617 (11) | C4—H4A | 0.9500 |
N1—C5 | 1.3654 (9) | C5—C6 | 1.5104 (11) |
N1—C1 | 1.3751 (10) | C7—C8 | 1.5036 (12) |
N1—H1N1 | 0.899 (15) | C7—H7A | 0.9800 |
N2—C11 | 1.3440 (11) | C7—H7B | 0.9800 |
N2—C12 | 1.3585 (10) | C7—H7C | 0.9800 |
N2—H1N2 | 0.954 (16) | C8—C12 | 1.3665 (12) |
N3—C11 | 1.3402 (10) | C8—C9 | 1.4169 (13) |
N3—H2N3 | 0.900 (16) | C9—C10 | 1.3681 (12) |
N3—H1N3 | 0.938 (15) | C9—H9A | 0.9500 |
C1—C2 | 1.4361 (11) | C10—C11 | 1.4172 (11) |
C2—C3 | 1.3622 (12) | C10—H10A | 0.9500 |
C2—H2A | 0.9500 | C12—H12A | 0.9500 |
C3—C4 | 1.4161 (12) | ||
C5—N1—C1 | 123.96 (7) | O2—C6—O3 | 126.76 (8) |
C5—N1—H1N1 | 118.0 (9) | O2—C6—C5 | 117.96 (8) |
C1—N1—H1N1 | 118.0 (9) | O3—C6—C5 | 115.27 (7) |
C11—N2—C12 | 122.96 (7) | C8—C7—H7A | 109.5 |
C11—N2—H1N2 | 116.1 (9) | C8—C7—H7B | 109.5 |
C12—N2—H1N2 | 121.0 (9) | H7A—C7—H7B | 109.5 |
C11—N3—H2N3 | 120.9 (9) | C8—C7—H7C | 109.5 |
C11—N3—H1N3 | 119.2 (9) | H7A—C7—H7C | 109.5 |
H2N3—N3—H1N3 | 118.4 (13) | H7B—C7—H7C | 109.5 |
O1—C1—N1 | 120.55 (7) | C12—C8—C9 | 116.59 (8) |
O1—C1—C2 | 124.11 (7) | C12—C8—C7 | 121.36 (8) |
N1—C1—C2 | 115.33 (7) | C9—C8—C7 | 122.05 (8) |
C3—C2—C1 | 121.23 (7) | C10—C9—C8 | 121.70 (8) |
C3—C2—H2A | 119.4 | C10—C9—H9A | 119.2 |
C1—C2—H2A | 119.4 | C8—C9—H9A | 119.2 |
C2—C3—C4 | 120.43 (8) | C9—C10—C11 | 119.28 (8) |
C2—C3—H3A | 119.8 | C9—C10—H10A | 120.4 |
C4—C3—H3A | 119.8 | C11—C10—H10A | 120.4 |
C5—C4—C3 | 118.57 (7) | N3—C11—N2 | 119.21 (8) |
C5—C4—H4A | 120.7 | N3—C11—C10 | 122.91 (8) |
C3—C4—H4A | 120.7 | N2—C11—C10 | 117.88 (7) |
C4—C5—N1 | 120.42 (7) | N2—C12—C8 | 121.60 (8) |
C4—C5—C6 | 123.23 (7) | N2—C12—H12A | 119.2 |
N1—C5—C6 | 116.33 (7) | C8—C12—H12A | 119.2 |
C5—N1—C1—O1 | 176.99 (7) | C4—C5—C6—O3 | 167.03 (9) |
C5—N1—C1—C2 | −2.64 (11) | N1—C5—C6—O3 | −11.36 (11) |
O1—C1—C2—C3 | −177.60 (9) | C12—C8—C9—C10 | −0.71 (14) |
N1—C1—C2—C3 | 2.02 (12) | C7—C8—C9—C10 | 179.51 (9) |
C1—C2—C3—C4 | 0.03 (15) | C8—C9—C10—C11 | 0.60 (14) |
C2—C3—C4—C5 | −1.64 (15) | C12—N2—C11—N3 | −179.75 (8) |
C3—C4—C5—N1 | 1.11 (14) | C12—N2—C11—C10 | −0.56 (12) |
C3—C4—C5—C6 | −177.22 (8) | C9—C10—C11—N3 | 179.19 (9) |
C1—N1—C5—C4 | 1.13 (13) | C9—C10—C11—N2 | 0.03 (13) |
C1—N1—C5—C6 | 179.56 (7) | C11—N2—C12—C8 | 0.45 (13) |
C4—C5—C6—O2 | −12.31 (13) | C9—C8—C12—N2 | 0.19 (13) |
N1—C5—C6—O2 | 169.31 (8) | C7—C8—C12—N2 | 179.97 (8) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1N1···O1i | 0.899 (15) | 2.011 (15) | 2.8922 (10) | 166.0 (16) |
N3—H2N3···O1 | 0.900 (16) | 2.245 (19) | 3.0373 (12) | 146.7 (15) |
N3—H2N3···O3i | 0.900 (16) | 2.408 (16) | 3.0916 (11) | 133.0 (15) |
N3—H1N3···O2ii | 0.938 (15) | 1.884 (16) | 2.8071 (12) | 167.7 (15) |
N2—H1N2···O3i | 0.954 (16) | 1.686 (18) | 2.6206 (11) | 165.7 (17) |
C3—H3A···O1iii | 0.95 | 2.33 | 3.2598 (11) | 166 |
C9—H9A···O1iv | 0.95 | 2.54 | 3.3750 (12) | 146 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, y+1/2, −z+1/2; (iii) x, −y+3/2, z−1/2; (iv) −x, y+1/2, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C6H9N2+·C6H4NO3− |
Mr | 247.25 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 100 |
a, b, c (Å) | 11.7093 (6), 10.4594 (6), 11.4590 (6) |
β (°) | 119.203 (1) |
V (Å3) | 1225.03 (11) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.45 × 0.35 × 0.23 |
Data collection | |
Diffractometer | Bruker SMART APEXII DUO CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2009) |
Tmin, Tmax | 0.957, 0.978 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 15984, 4430, 3745 |
Rint | 0.027 |
(sin θ/λ)max (Å−1) | 0.759 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.039, 0.116, 1.02 |
No. of reflections | 4430 |
No. of parameters | 180 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.43, −0.21 |
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···O1i | 0.899 (15) | 2.011 (15) | 2.8922 (10) | 166.0 (16) |
N3—H2N3···O1 | 0.900 (16) | 2.245 (19) | 3.0373 (12) | 146.7 (15) |
N3—H2N3···O3i | 0.900 (16) | 2.408 (16) | 3.0916 (11) | 133.0 (15) |
N3—H1N3···O2ii | 0.938 (15) | 1.884 (16) | 2.8071 (12) | 167.7 (15) |
N2—H1N2···O3i | 0.954 (16) | 1.686 (18) | 2.6206 (11) | 165.7 (17) |
C3—H3A···O1iii | 0.95 | 2.33 | 3.2598 (11) | 166 |
C9—H9A···O1iv | 0.95 | 2.54 | 3.3750 (12) | 146 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, y+1/2, −z+1/2; (iii) x, −y+3/2, z−1/2; (iv) −x, y+1/2, −z+1/2. |
Footnotes
‡Thomson Reuters ResearcherID: A-5599-2009.
Acknowledgements
The authors thank the Malaysian Government and Universiti Sains Malaysia (USM) for research facilities and the Fundamental Research Grant Scheme (FRGS) No. 203/PFIZIK/6711171 to conduct this work. KT thanks The Academy of Sciences for the Developing World and USM for a TWAS–USM fellowship.
References
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2-Aminopyridine and its derivatives are some of the most frequently used synthons in supramolecular chemistry based on hydrogen bonds (Banerjee & Murugavel, 2004; Bis & Zaworotko, 2005; Bis et al., 2006). 6-Hydroxypicolinic acid has interesting characteristics: firstly, it was characterized by a similar enol-keto tautomerism due to the labile hydrogen atom of –OH group in α-position migrating easily to the basic pyridine N atom; secondly, the multiple coordination sites such as the carbonyl oxygen, the amide nitrogen and carboxylate oxygen atoms are able to coordinate with various metal ions (Sun et al., 2004; Soares-Santos et al., 2003). In order to study some interesting hydrogen bonding interactions of this compound, the synthesis and structure of the title salt is presented here.
The asymmetric unit of the title compound contains a 2-amino-5-methylpyridinium cation and a 6-oxo-1,6-dihydropyridine-2-carboxylate anion (Fig. 1). The 2-amino-5-methylpyridinium cation is planar, with a maximum deviation of 0.004 (1) Å for atoms N2 and C9. In the cation, a wider than normal angle [C11—N2—C12 = 122.96 (8)°] is subtended at the protonated N2 atom. The bond lengths (Allen et al., 1987) and angles are normal. The anion exists in the keto-enol tautomerism of the –CONH moiety. Similar form was also observed in the crystal structure of 2-oxo-1,2-dihydropyridine-6-carboxylic acid (Sawada & Ohashi, 1998).
In the crystal (Fig. 2), the 6-oxo-1,6-dihydropyridine-2-carboxylate anion are centrosymmetrically paired through a pair of N1—H1N1···O1i hydrogen bonds (symmetry code in Table 1) to form an R22(8) (Bernstein et al., 1995) ring motif. These motifs are further self-organized through N—H···O hydrogen bonds to generate an array of four hydrogen bonds, resulting in the rings with R22(8), sandwiched by two R22(7). One of the O atoms of the carboxylate group acts as an acceptors of bifurcated N2—H1N2···O3i and N3—H2N3···O3i hydrogen bonds (symmetry code in Table 1) with the protonated pyridine and amine N atoms of the cation, forming an R21(6) ring motif. The crystal structure are further stabilized by strong N3—H1N3···O2ii and weak C3—H3A···O1iii and C9—H9A···O1iv hydrogen bonds (symmetry codes in Table 1), resulting a three-dimensional network.