Download citation
Download citation
link to html
The title compound, 2-amino-5-carboxy­pyridinium chloride, C6H7N2O2+·Cl-, was isolated from a 1 M HCl aqueous solution containing 2-amino-5-cyano­pyridine. The structure is held together by extensive hydrogen bonding between the chloride ions and the carboxylic acid, amino and pyridinium H atoms. The mol­ecules pack as sheets, with the sheets at a distance of 3.21 (3) Å from one another.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270199014821/ta1270sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270199014821/ta1270Isup2.hkl
Contains datablock I

CCDC reference: 143244

Comment top

In our laboratories we are interested in the preparation and study of low-dimensional magnetic lattices which have the general formula A2MX4, where M is a 2+ transition metal ion, X = Cl or Br and A is a protonated organic base. Usually, these compounds pack in crystal lattices that create interesting low-dimensional magnetic lattices. The magnetic lattice arises from interactions between the MX4- ions. The nature of these interactions is controlled by the crystal lattice, which changes as the organic base is changed. Aromatic compounds containing substituents in the 5-position, such 2-amino-5-methylpyridine (Place & Willet, 1987) and 2-amino-5-chloropyridine (Albrecht et al., 1997, 1999; Hammar et al., 1997) have been shown to have very interesting magnetic properties. 2-Amino-5-cyanopyridine was synthesized according to the procedure of Gregory et al. (1947) in order to compare its suitability as a base with that of the previously mentioned derivatives. We have prepared metal complexes of 2-amino-5-cyanopyridine (J. Giantsidis & M. M. Turnbull, unpublished results) and were interested in what kind of interactions we might expect between the organic groups themselves. Therefore, 6-aminonicotinic acid hydrochloride, (I), was crystallized from a solution of 2-amino-5-cyanopyridine in aqueous HCl and its structure is presented here.

The aromatic ring of (I) is planar, with a mean plane deviation of 0.0047 Å. The carboxyl and the amino groups are canted from that plane, likely as a result of hydrogen bonding in the lattice.

The crystal lattice exists as nearly planar sheets of protonated 6-aminonicotinic acid molecules and chloride ions that run roughly parallel to the B-face. The plane of the ring is canted 3.8 (2)° relative the B-face. The ring axis, defined as the C2—C5 vector, is inclined at an angle of 16.4 (2)° relative to the c axis. The layers are close together [3.21 (3) Å], but are not linked by hydrogen bonding. However, within the sheets, hydrogen bonds form from the pyridinium proton to the chloride ion, and from one of the amino protons to the choride ion (Table 2). Also, there is a weak hydrogen bond from the other amino proton to the carbonyl oxygen. Even though the distance between N2 and O2 is the shortest, the angle is far from linear, resulting in a weaker interaction. An additional hydrogen bond forms from the carboxylic proton to the chloride ion.

Crystals of the 5-cyano compound are being prepared under anhydrous conditions and the use of 6-aminonicotinic acid for the preparation of low-dimensional magnetic lattices is underway.

Experimental top

Crystals of (I) were grown by dissolving 2-amino-5-cyanopyridine in water (37 ml) and concentrated HCl (3 ml). Colourless rod-shaped crystals were collected after slow evaporation of the solvent. Infrared spectra showed, and X-ray data confirmed, that the cyano group had been hydrolyzed, resulting in the title compound. We were very surprised that under these mild conditions the cyano group hydrolyzed to the carboxylic acid. It is known that 6-aminonicotinic acid can be prepared by hydrolysis of 2-amino-5-cyanopyridine, but at elevated temperature and significantly higher HCl concentrations (Binz & Rath, 1928).

Computing details top

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997b); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) showing 50% probability displacement ellipsoids and the atom-numbering scheme. H atoms are drawn as spheres of arbitrary radii.
[Figure 2] Fig. 2. Packing diagram for (I) showing the hydrogen bonding and the relationship between successive sheets within the lattice.
2-Amino-5-carboxypyridinium chloride top
Crystal data top
C6H7N2O2+·ClZ = 2
Mr = 174.59F(000) = 180
Triclinic, P1Dx = 1.502 Mg m3
a = 6.844 (2) ÅMo Kα radiation, λ = 0.71073 Å
b = 6.908 (2) ÅCell parameters from 4366 reflections
c = 9.061 (3) Åθ = 2.3–26.4°
α = 101.398 (4)°µ = 0.44 mm1
β = 90.799 (4)°T = 170 K
γ = 112.515 (3)°Prism, colourless
V = 386.01 (19) Å30.80 × 0.54 × 0.37 mm
Data collection top
Siemens CCD area detector
diffractometer
1566 independent reflections
Radiation source: fine-focus sealed tube1459 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.025
ϕ and ω scansθmax = 26.4°, θmin = 2.3°
Absorption correction: empirical (using intensity measurements)
(SADABS; Sheldrick, 1996)
h = 87
Tmin = 0.532, Tmax = 0.849k = 88
4979 measured reflectionsl = 1111
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.034Hydrogen site location: difference Fourier map
wR(F2) = 0.091H atoms treated by a mixture of independent and constrained refinement
S = 1.14Calculated w = 1/[σ2(Fo2) + (0.0467P)2 + 0.1511P]
where P = (Fo2 + 2Fc2)/3
1566 reflections(Δ/σ)max < 0.001
112 parametersΔρmax = 0.27 e Å3
0 restraintsΔρmin = 0.27 e Å3
Crystal data top
C6H7N2O2+·Clγ = 112.515 (3)°
Mr = 174.59V = 386.01 (19) Å3
Triclinic, P1Z = 2
a = 6.844 (2) ÅMo Kα radiation
b = 6.908 (2) ŵ = 0.44 mm1
c = 9.061 (3) ÅT = 170 K
α = 101.398 (4)°0.80 × 0.54 × 0.37 mm
β = 90.799 (4)°
Data collection top
Siemens CCD area detector
diffractometer
1566 independent reflections
Absorption correction: empirical (using intensity measurements)
(SADABS; Sheldrick, 1996)
1459 reflections with I > 2σ(I)
Tmin = 0.532, Tmax = 0.849Rint = 0.025
4979 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0340 restraints
wR(F2) = 0.091H atoms treated by a mixture of independent and constrained refinement
S = 1.14Δρmax = 0.27 e Å3
1566 reflectionsΔρmin = 0.27 e Å3
112 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
xyzUiso*/Ueq
Cl0.06059 (6)0.71023 (7)0.34461 (4)0.02601 (16)
N10.2274 (2)0.7457 (2)0.40259 (16)0.0221 (3)
H10.138 (4)0.738 (3)0.475 (3)0.027*
C20.4106 (3)0.7616 (2)0.44241 (18)0.0213 (3)
N20.4539 (3)0.7663 (2)0.58491 (17)0.0264 (3)
H2A0.578 (4)0.762 (3)0.612 (3)0.032*
H2B0.374 (4)0.750 (3)0.652 (3)0.032*
C30.5497 (3)0.7698 (3)0.32878 (19)0.0262 (4)
H30.68150.77770.35320.031*
C40.4937 (3)0.7667 (3)0.1843 (2)0.0273 (4)
H40.58670.77300.10840.033*
C50.2992 (3)0.7534 (3)0.14738 (19)0.0240 (4)
C60.1700 (3)0.7422 (3)0.25972 (19)0.0234 (4)
H60.03880.73170.23730.028*
C70.2376 (3)0.7500 (3)0.0101 (2)0.0287 (4)
O10.0572 (2)0.7249 (3)0.02368 (15)0.0397 (4)
H1O0.030 (4)0.717 (4)0.111 (3)0.048*
O20.3430 (3)0.7716 (3)0.11382 (15)0.0474 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl0.0249 (2)0.0351 (3)0.0205 (2)0.01343 (18)0.00302 (16)0.00815 (16)
N10.0227 (7)0.0266 (7)0.0178 (7)0.0101 (6)0.0042 (6)0.0055 (5)
C20.0234 (8)0.0202 (8)0.0191 (8)0.0067 (6)0.0009 (6)0.0054 (6)
N20.0268 (8)0.0355 (8)0.0182 (7)0.0126 (7)0.0022 (6)0.0081 (6)
C30.0233 (9)0.0342 (9)0.0245 (9)0.0136 (7)0.0045 (7)0.0091 (7)
C40.0276 (9)0.0355 (9)0.0218 (8)0.0144 (8)0.0075 (7)0.0085 (7)
C50.0274 (9)0.0263 (8)0.0184 (8)0.0105 (7)0.0021 (7)0.0055 (6)
C60.0236 (8)0.0253 (8)0.0211 (8)0.0096 (7)0.0001 (6)0.0050 (6)
C70.0315 (10)0.0347 (9)0.0210 (9)0.0136 (8)0.0011 (7)0.0075 (7)
O10.0425 (9)0.0658 (10)0.0206 (7)0.0306 (8)0.0005 (6)0.0123 (7)
O20.0501 (9)0.0869 (12)0.0207 (7)0.0401 (9)0.0106 (6)0.0189 (7)
Geometric parameters (Å, º) top
N1—C21.350 (2)C4—C51.409 (3)
N1—C61.355 (2)C4—H40.9500
N1—H10.91 (2)C5—C61.367 (2)
C2—N21.330 (2)C5—C71.489 (2)
C2—C31.420 (2)C6—H60.9500
N2—H2A0.87 (3)C7—O21.213 (2)
N2—H2B0.84 (2)C7—O11.318 (2)
C3—C41.365 (2)O1—H1O0.83 (3)
C3—H30.9500
C2—N1—C6122.97 (15)C3—C4—H4119.7
C2—N1—H1118.4 (13)C5—C4—H4119.8
C6—N1—H1118.6 (13)C6—C5—C4118.34 (16)
N2—C2—N1119.18 (16)C6—C5—C7121.11 (16)
N2—C2—C3123.12 (17)C4—C5—C7120.55 (16)
N1—C2—C3117.70 (15)N1—C6—C5120.65 (16)
C2—N2—H2A118.3 (15)N1—C6—H6119.7
C2—N2—H2B121.1 (15)C5—C6—H6119.6
H2A—N2—H2B120 (2)O2—C7—O1124.46 (17)
C4—C3—C2119.91 (16)O2—C7—C5122.64 (17)
C4—C3—H3120.0O1—C7—C5112.90 (15)
C2—C3—H3120.0C7—O1—H1O110.9 (19)
C3—C4—C5120.43 (16)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···Cli0.91 (2)2.17 (2)3.0766 (16)177.1 (19)
N2—H2A···Clii0.87 (3)2.37 (3)3.234 (2)170 (2)
O1—H1O···Cl0.83 (3)2.21 (3)3.0381 (16)177 (2)
N2—H2B···O2i0.84 (2)2.17 (2)2.847 (2)138 (2)
Symmetry codes: (i) x, y, z1; (ii) x1, y, z1.

Experimental details

Crystal data
Chemical formulaC6H7N2O2+·Cl
Mr174.59
Crystal system, space groupTriclinic, P1
Temperature (K)170
a, b, c (Å)6.844 (2), 6.908 (2), 9.061 (3)
α, β, γ (°)101.398 (4), 90.799 (4), 112.515 (3)
V3)386.01 (19)
Z2
Radiation typeMo Kα
µ (mm1)0.44
Crystal size (mm)0.80 × 0.54 × 0.37
Data collection
DiffractometerSiemens CCD area detector
diffractometer
Absorption correctionEmpirical (using intensity measurements)
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.532, 0.849
No. of measured, independent and
observed [I > 2σ(I)] reflections
4979, 1566, 1459
Rint0.025
(sin θ/λ)max1)0.626
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.034, 0.091, 1.14
No. of reflections1566
No. of parameters112
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.27, 0.27

Computer programs: SMART (Siemens, 1996), SAINT (Siemens, 1996), SAINT, SHELXS97 (Sheldrick, 1997a), SHELXL97 (Sheldrick, 1997b), SHELXL97.

Selected geometric parameters (Å, º) top
N1—C21.350 (2)C4—C51.409 (3)
N1—C61.355 (2)C5—C61.367 (2)
C2—N21.330 (2)C5—C71.489 (2)
C2—C31.420 (2)C7—O21.213 (2)
C3—C41.365 (2)C7—O11.318 (2)
C2—N1—C6122.97 (15)C6—C5—C4118.34 (16)
C2—N1—H1118.4 (13)C6—C5—C7121.11 (16)
C6—N1—H1118.6 (13)C4—C5—C7120.55 (16)
N2—C2—N1119.18 (16)N1—C6—C5120.65 (16)
N2—C2—C3123.12 (17)O2—C7—O1124.46 (17)
N1—C2—C3117.70 (15)O2—C7—C5122.64 (17)
C4—C3—C2119.91 (16)O1—C7—C5112.90 (15)
C3—C4—C5120.43 (16)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···Cli0.91 (2)2.17 (2)3.0766 (16)177.1 (19)
N2—H2A···Clii0.87 (3)2.37 (3)3.234 (2)170 (2)
O1—H1O···Cl0.83 (3)2.21 (3)3.0381 (16)177 (2)
N2—H2B···O2i0.84 (2)2.17 (2)2.847 (2)138 (2)
Symmetry codes: (i) x, y, z1; (ii) x1, y, z1.
 

Follow Acta Cryst. C
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds