The synthesis, crystallization and structure determination of the title compound, nicotinic acid hydrochloride, C6H6NO2+·Cl-, is part of a project on charge densities in crystals. The good quality crystals of the compound composed of light elements and in centrosymmetric space group P21/m indicate their suitability for charge-density study.
Supporting information
CCDC reference: 155890
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (C-C) = 0.004 Å
- R factor = 0.031
- wR factor = 0.077
- Data-to-parameter ratio = 8.5
checkCIF results
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ADDSYM reports no extra symmetry
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An 0.1 M methanol solution of nicotinic acid (99% pure) was mixed with an
equimolar amount of an 0.1 M methanol solution of hydrochloric acid
(36% water solution). Crystals suitable for structure determination were grown
by very slow evaporation of the mixture.
Data collection: COLLECT (Nonius, 1995); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997) and
JANA2000 (Petricek & Dusek, 2000); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1990); software used to prepare material for publication: SHELXL97.
3-carboxypyridinium chloride
top
Crystal data top
C6H6O2N+·Cl− | F(000) = 164 |
Mr = 159.57 | Dx = 1.500 Mg m−3 |
Monoclinic, P21/m | Mo Kα radiation, λ = 0.71070 Å |
a = 7.1704 (3) Å | Cell parameters from 2406 reflections |
b = 6.6685 (6) Å | θ = 1–25° |
c = 7.4937 (6) Å | µ = 0.47 mm−1 |
β = 99.555 (5)° | T = 293 K |
V = 353.35 (5) Å3 | Prism, translucent colourless |
Z = 2 | 0.3 × 0.2 × 0.2 mm |
Data collection top
Nonius KappaCCD diffractometer | 608 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.015 |
Graphite monochromator | θmax = 25.0°, θmin = 2.8° |
Detector resolution: 0.110 pixels mm-1 | h = −8→8 |
ϕ and ω scans | k = 0→7 |
2406 measured reflections | l = 0→8 |
679 independent reflections | |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.031 | All H-atom parameters refined |
wR(F2) = 0.077 | w = 1/[σ2(Fo2) + (0.0263P)2 + 0.1615P] where P = (Fo2 + 2Fc2)/3 |
S = 1.11 | (Δ/σ)max < 0.001 |
679 reflections | Δρmax = 0.21 e Å−3 |
80 parameters | Δρmin = −0.22 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.090 (17) |
Crystal data top
C6H6O2N+·Cl− | V = 353.35 (5) Å3 |
Mr = 159.57 | Z = 2 |
Monoclinic, P21/m | Mo Kα radiation |
a = 7.1704 (3) Å | µ = 0.47 mm−1 |
b = 6.6685 (6) Å | T = 293 K |
c = 7.4937 (6) Å | 0.3 × 0.2 × 0.2 mm |
β = 99.555 (5)° | |
Data collection top
Nonius KappaCCD diffractometer | 608 reflections with I > 2σ(I) |
2406 measured reflections | Rint = 0.015 |
679 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.031 | 0 restraints |
wR(F2) = 0.077 | All H-atom parameters refined |
S = 1.11 | Δρmax = 0.21 e Å−3 |
679 reflections | Δρmin = −0.22 e Å−3 |
80 parameters | |
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 | |
Cl1 | 0.71876 (9) | 0.2500 | 0.14792 (8) | 0.0409 (3) | |
O1 | 0.5551 (2) | 0.2500 | 0.4790 (2) | 0.0510 (6) | |
O2 | 0.2816 (3) | 0.2500 | 0.2907 (2) | 0.0765 (9) | |
C7 | 0.3704 (4) | 0.2500 | 0.4408 (3) | 0.0427 (7) | |
C1 | 0.2747 (3) | 0.2500 | 0.6036 (3) | 0.0350 (6) | |
C2 | 0.3771 (4) | 0.2500 | 0.7746 (3) | 0.0353 (6) | |
N3 | 0.2875 (3) | 0.2500 | 0.9170 (3) | 0.0369 (6) | |
C4 | 0.1005 (4) | 0.2500 | 0.9007 (4) | 0.0443 (7) | |
C5 | −0.0081 (4) | 0.2500 | 0.7323 (4) | 0.0501 (8) | |
C6 | 0.0793 (4) | 0.2500 | 0.5825 (4) | 0.0437 (7) | |
H1 | 0.610 (6) | 0.2500 | 0.363 (6) | 0.093 (13)* | |
H2 | 0.505 (4) | 0.2500 | 0.801 (3) | 0.038 (7)* | |
H3 | 0.359 (4) | 0.2500 | 1.022 (4) | 0.050 (9)* | |
H4 | 0.050 (4) | 0.2500 | 1.006 (4) | 0.047 (8)* | |
H5 | −0.139 (5) | 0.2500 | 0.728 (4) | 0.059 (9)* | |
H6 | 0.012 (4) | 0.2500 | 0.470 (4) | 0.046 (8)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cl1 | 0.0355 (4) | 0.0539 (5) | 0.0344 (4) | 0.000 | 0.0089 (3) | 0.000 |
O1 | 0.0328 (11) | 0.0905 (17) | 0.0301 (10) | 0.000 | 0.0065 (8) | 0.000 |
O2 | 0.0413 (12) | 0.166 (3) | 0.0220 (10) | 0.000 | 0.0035 (8) | 0.000 |
C7 | 0.0375 (15) | 0.0633 (19) | 0.0271 (13) | 0.000 | 0.0052 (11) | 0.000 |
C1 | 0.0328 (13) | 0.0470 (17) | 0.0250 (12) | 0.000 | 0.0038 (10) | 0.000 |
C2 | 0.0309 (14) | 0.0467 (17) | 0.0281 (13) | 0.000 | 0.0047 (10) | 0.000 |
N3 | 0.0394 (13) | 0.0475 (14) | 0.0229 (11) | 0.000 | 0.0022 (9) | 0.000 |
C4 | 0.0438 (16) | 0.0583 (19) | 0.0340 (15) | 0.000 | 0.0161 (12) | 0.000 |
C5 | 0.0311 (15) | 0.079 (2) | 0.0407 (16) | 0.000 | 0.0086 (12) | 0.000 |
C6 | 0.0350 (14) | 0.065 (2) | 0.0290 (14) | 0.000 | −0.0007 (11) | 0.000 |
Geometric parameters (Å, º) top
O1—C7 | 1.308 (3) | C5—C6 | 1.373 (4) |
O2—C7 | 1.197 (3) | O1—H1 | 1.01 (4) |
C7—C1 | 1.496 (3) | C2—H2 | 0.91 (3) |
C1—C2 | 1.367 (3) | N3—H3 | 0.86 (3) |
C1—C6 | 1.383 (4) | C4—H4 | 0.92 (3) |
C2—N3 | 1.333 (3) | C5—H5 | 0.93 (3) |
N3—C4 | 1.326 (4) | C6—H6 | 0.90 (3) |
C4—C5 | 1.369 (4) | | |
| | | |
O2—C7—O1 | 124.5 (2) | C4—N3—H3 | 121 (2) |
C7—O1—H1 | 110 (2) | C2—N3—H3 | 116 (2) |
O2—C7—C1 | 121.5 (2) | N3—C4—C5 | 119.8 (2) |
O1—C7—C1 | 114.0 (2) | N3—C4—H4 | 117.2 (18) |
C2—C1—C6 | 118.9 (2) | C5—C4—H4 | 123.0 (18) |
C2—C1—C7 | 121.1 (2) | C4—C5—C6 | 119.1 (3) |
C6—C1—C7 | 120.0 (2) | C4—C5—H5 | 116.7 (19) |
N3—C2—C1 | 119.6 (2) | C6—C5—H5 | 124.2 (19) |
N3—C2—H2 | 115.5 (17) | C5—C6—C1 | 119.8 (2) |
C1—C2—H2 | 124.8 (17) | C5—C6—H6 | 121.1 (18) |
C4—N3—C2 | 122.7 (2) | C1—C6—H6 | 119.0 (18) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···Cl1 | 1.01 (4) | 1.90 (4) | 2.9154 (19) | 179 (1) |
N3—H3···O2i | 0.86 (3) | 2.18 (3) | 2.808 (3) | 130 (3) |
N3—H3···Cl1i | 0.86 (3) | 2.60 (3) | 3.283 (2) | 137 (3) |
Symmetry code: (i) x, y, z+1. |
Experimental details
Crystal data |
Chemical formula | C6H6O2N+·Cl− |
Mr | 159.57 |
Crystal system, space group | Monoclinic, P21/m |
Temperature (K) | 293 |
a, b, c (Å) | 7.1704 (3), 6.6685 (6), 7.4937 (6) |
β (°) | 99.555 (5) |
V (Å3) | 353.35 (5) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.47 |
Crystal size (mm) | 0.3 × 0.2 × 0.2 |
|
Data collection |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2406, 679, 608 |
Rint | 0.015 |
(sin θ/λ)max (Å−1) | 0.595 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.031, 0.077, 1.11 |
No. of reflections | 679 |
No. of parameters | 80 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.21, −0.22 |
Selected geometric parameters (Å, º) topO1—C7 | 1.308 (3) | C5—C6 | 1.373 (4) |
O2—C7 | 1.197 (3) | O1—H1 | 1.01 (4) |
C7—C1 | 1.496 (3) | C2—H2 | 0.91 (3) |
C1—C2 | 1.367 (3) | N3—H3 | 0.86 (3) |
C1—C6 | 1.383 (4) | C4—H4 | 0.92 (3) |
C2—N3 | 1.333 (3) | C5—H5 | 0.93 (3) |
N3—C4 | 1.326 (4) | C6—H6 | 0.90 (3) |
C4—C5 | 1.369 (4) | | |
| | | |
O2—C7—O1 | 124.5 (2) | O2—C7—C1 | 121.5 (2) |
C7—O1—H1 | 110 (2) | O1—C7—C1 | 114.0 (2) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···Cl1 | 1.01 (4) | 1.90 (4) | 2.9154 (19) | 179 (1) |
N3—H3···O2i | 0.86 (3) | 2.18 (3) | 2.808 (3) | 130 (3) |
N3—H3···Cl1i | 0.86 (3) | 2.60 (3) | 3.283 (2) | 137 (3) |
Symmetry code: (i) x, y, z+1. |
The crystal structure of the title compound, (I), is built of protonated nicotinic acid cations C6H6NO2+ and chlorine anions. As expected, the nicotinic acid is protonated on the aromatic ring N atom and forms a 3-carboxypyridinium cation (Fig. 1). Interatomic distances and angles are within usual limits (Table 1).
Electrostatic interactions among the ions in the crystal are supplemented with hydrogen bonds (Table 1). The 3-carboxypyridinium O1 atom acts as donor to Cl1 within the asymmetric unit, the 3-carboxypyridinium N1 atom acts as donor to the 3-carboxypyridinium O2(x, y, z + 1) atom and, simultaneously,to Cl1(x, y, z + 1). In total, there is one two-centre and one three-centre hydrogen bond per cation (Table 2).
The compound crystallizes in the space group P21/m. Both ions present in the crystal are situated in the special Wyckoff positions e of multiplicity 2 and site symmetry m. This means that both ions lie on the mirror plane (x, 1/4, z) and the 3-carboxypyridinium cation is strictly planar. As a result, there are parallel planar layers in the crystal structure, on the mirror planes of space group P21/m. The distance between the layers is 3.3343 (3) Å, half of the lattice parameter b.
Within the layer, there are chains of larger 3-carboxypyridinium cations alternating with smaller Cl- anions; they are linked through hydrogen bonds (Fig. 2).
There are no hydrogen-bonding interactions between the layers; examination of the structure with PLATON (Spek, 1990) shows that there are no solvent-accessible voids in the unit cell.
This work is a preliminary study, part of a project on charge densities in crystals (Slouf, 2000). The structure of nicotinic acid itself has already been determined (Wright & King, 1953) and redetermined (Gupta & Kumar, 1975; Kutoglu & Scheringer, 1983). In the Cambridge Structural Database (Allen & Kennard, 1993), neither the structure of 3-carboxypyridinium, which is reported here, nor any charge–density study on nicotinic acid was found.