The structure of pyridine-2,6-dicarboxylic acid, C
7H
5NO
4, has been determined at 0.71 Å resolution. The molecule is located on a site with mirror symmetry. A one-dimensional supramolecular structure is stabilized in the solid state through a strong symmetric double hydrogen bond, with H
O distances of 1.86 (3) Å and O-H
O angles of 167 (3) and 171 (5)°. This arrangement is similar but not identical to that reported for the isoelectronic isophthalic acid (benzene-1,3-dicarboxylic acid).
Supporting information
CCDC reference: 184496
Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXL97.
2,6-pyridinedicarboxylic acid
top
Crystal data top
C7H5NO4 | F(000) = 172 |
Mr = 167.12 | Dx = 1.639 Mg m−3 |
Monoclinic, P21/m | Melting point: 525 K |
Hall symbol: -P2yb | Mo Kα radiation, λ = 0.71073 Å |
a = 3.7663 (6) Å | Cell parameters from 70 reflections |
b = 16.1667 (12) Å | θ = 3.9–18.4° |
c = 5.5705 (4) Å | µ = 0.14 mm−1 |
β = 93.156 (7)° | T = 300 K |
V = 338.67 (6) Å3 | Irregular, colourless |
Z = 2 | 0.7 × 0.4 × 0.4 mm |
Data collection top
Bruker P4 diffractometer | Rint = 0.036 |
Radiation source: fine-focus sealed tube | θmax = 30.0°, θmin = 2.5° |
Graphite monochromator | h = −5→5 |
ω scans | k = −22→22 |
3920 measured reflections | l = −7→7 |
1021 independent reflections | 3 standard reflections every 97 reflections |
937 reflections with I > 2σ(I) | intensity decay: 1% |
Refinement top
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)] = 0.040 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.121 | All H-atom parameters refined |
S = 1.06 | w = 1/[σ2(Fo2) + (0.0827P)2 + 0.0236P] where P = (Fo2 + 2Fc2)/3 |
1021 reflections | (Δ/σ)max = 0.001 |
74 parameters | Δρmax = 0.34 e Å−3 |
2 restraints | Δρmin = −0.18 e Å−3 |
Special details top
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
C1 | 0.1489 (2) | 0.60137 (5) | 0.64848 (17) | 0.0331 (2) | |
C2 | 0.2615 (2) | 0.67993 (5) | 0.77301 (14) | 0.0287 (2) | |
C3 | 0.4513 (3) | 0.67632 (5) | 0.99546 (17) | 0.0337 (2) | |
H3 | 0.516 (4) | 0.6252 (12) | 1.070 (3) | 0.049 (4)* | |
C4 | 0.5489 (3) | 0.7500 | 1.1093 (2) | 0.0349 (3) | |
H4 | 0.698 (7) | 0.7500 | 1.272 (5) | 0.063 (7)* | |
N1 | 0.1650 (3) | 0.7500 | 0.66094 (18) | 0.0289 (2) | |
O1 | 0.2503 (3) | 0.53435 (5) | 0.75157 (16) | 0.0580 (3) | |
H1 | 0.158 (7) | 0.4969 (19) | 0.688 (5) | 0.054 (6)* | 0.66 (3) |
O2 | −0.0354 (2) | 0.60406 (4) | 0.45566 (14) | 0.0490 (3) | |
H2 | −0.119 (12) | 0.564 (2) | 0.401 (8) | 0.054 (6)* | 0.34 (3) |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C1 | 0.0399 (4) | 0.0239 (4) | 0.0346 (4) | −0.0008 (3) | −0.0070 (3) | 0.0025 (3) |
C2 | 0.0329 (4) | 0.0239 (4) | 0.0287 (4) | 0.0000 (2) | −0.0039 (3) | 0.0012 (2) |
C3 | 0.0384 (4) | 0.0318 (5) | 0.0300 (4) | 0.0012 (3) | −0.0058 (3) | 0.0044 (3) |
C4 | 0.0393 (6) | 0.0381 (6) | 0.0264 (5) | 0.000 | −0.0069 (4) | 0.000 |
N1 | 0.0345 (5) | 0.0235 (4) | 0.0281 (4) | 0.000 | −0.0050 (3) | 0.000 |
O1 | 0.0862 (6) | 0.0237 (4) | 0.0600 (5) | −0.0001 (3) | −0.0339 (5) | 0.0061 (3) |
O2 | 0.0722 (6) | 0.0272 (4) | 0.0444 (5) | −0.0014 (3) | −0.0262 (4) | −0.0003 (3) |
Geometric parameters (Å, º) top
C1—O1 | 1.2750 (10) | C3—H3 | 0.95 (2) |
C1—O2 | 1.2472 (12) | C4—C3i | 1.3894 (11) |
C1—C2 | 1.4973 (11) | C4—H4 | 1.04 (3) |
C2—N1 | 1.3342 (9) | N1—C2i | 1.3342 (9) |
C2—C3 | 1.3973 (12) | O1—H1 | 0.77 (3) |
C3—C4 | 1.3894 (11) | O2—H2 | 0.77 (3) |
| | | |
O2—C1—O1 | 123.81 (9) | C2—C3—H3 | 122.0 (11) |
O2—C1—C2 | 119.96 (8) | C3—C4—C3i | 118.04 (12) |
O1—C1—C2 | 116.23 (8) | C3—C4—H4 | 120.96 (6) |
N1—C2—C3 | 124.29 (8) | C3i—C4—H4 | 120.96 (8) |
N1—C2—C1 | 116.14 (8) | C2i—N1—C2 | 116.22 (10) |
C3—C2—C1 | 119.57 (7) | C1—O1—H1 | 110 (2) |
C4—C3—C2 | 118.58 (8) | C1—O2—H2 | 120 (4) |
C4—C3—H3 | 119.4 (11) | | |
| | | |
O2—C1—C2—N1 | −2.51 (15) | N1—C2—C3—C4 | −0.23 (17) |
O1—C1—C2—N1 | 177.88 (9) | C1—C2—C3—C4 | −179.16 (8) |
O2—C1—C2—C3 | 176.50 (9) | C2—C3—C4—C3i | 0.16 (19) |
O1—C1—C2—C3 | −3.11 (14) | C3—C2—N1—C2i | 0.28 (17) |
N1—C2—C3—C4 | −0.23 (17) | C1—C2—N1—C2i | 179.24 (6) |
C1—C2—C3—C4 | −179.16 (8) | H4—C4—C3—H3 | 2.0 (17) |
C2—C3—C4—C3i | 0.16 (19) | H4—C4—C3—C2 | −177.8 (15) |
C3—C2—N1—C2i | 0.28 (17) | H3—C3—C2—C1 | 1.1 (10) |
C1—C2—N1—C2i | 179.24 (6) | H3—C3—C2—N1 | 180.0 (10) |
O2—C1—C2—N1 | −2.51 (15) | H1—O1—C1—O2 | −9 (2) |
O1—C1—C2—N1 | 177.88 (9) | H1—O1—C1—C2 | 171 (2) |
O2—C1—C2—C3 | 176.50 (9) | H2—O2—C1—O1 | 9 (4) |
O1—C1—C2—C3 | −3.11 (14) | H2—O2—C1—C2 | −170 (4) |
Symmetry code: (i) x, −y+3/2, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O2ii | 0.77 (3) | 1.86 (3) | 2.6252 (12) | 167 (3) |
O2—H2···O1ii | 0.77 (3) | 1.86 (3) | 2.6252 (12) | 171 (5) |
Symmetry code: (ii) −x, −y+1, −z+1. |