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Acta Cryst. (2010). E66, o1365    [ doi:10.1107/S1600536810017423 ]

3,5-Dicarboxy-2,6-dimethylpyridinium chloride dihydrate

J.-Y. Yao

Abstract top

In the title compound, C9H10NO4+·Cl-·2H2O, both the cation and the anion have crystallographic twofold rotation symmetry; in the former, one N and one C atom lie on the rotation axis. In the crystal structure, the ions and water molecules are linked via O-H...O, O-H...Cl and N-H...Cl hydrogen bonds into layers parallel to (101).

Comment top

Organic and inorganic complexes or salts can develop supramolecular structures via multiple hydrogen-bonding systems by self-assembly of components which contain abundant hydrogen-bonding sites (Rowan & Holt, 1997). The present study is a part of systematic investigation of ferroelectric materials (Ye et al., 2008; Hang et al., 2009) that include metal-organic coordination compounds with organic ligands or compounds whose structures consist both of organic and inorganic building fragments.

The asymmetric unit of the title compound is composed of a half of a 3,5-dicarboxy-2,6-dimethylpyridinium cation, a half of a chloride anion and a water molecule. Both cation and anion have crystallographically imposed twofold rotation symmetry (Fig. 1). In the cation, the C—O bond lengths in the carboxylic group (C1—O1 = 1.300 (2) Å; C1—O2 = 1.218 (2) Å) conform to the expected values (Allen, 2002). The C3—N1—C3 angle of 126.6 (2) ° corresponds closely to the average value found in protonated pyridinium ions (122.0 (2) °). In the crystal structure (Fig. 2), the 3,5-dicarboxy-2,6-dimethylpyridinium cations, the chloride anions and the water molecules are linked via O—H···O, O—H···Cl and N—H···Cl hydrogen bonds (Table 1) to form two-dimensional layers parallel to the (101) plane. Dielectric studies (capacitance and dielectric loss measurements) were performed on powder samples of the title compound pressed into tablets on the surfaces of which a conducting carbon glue was deposited. The automatic impedance TongHui 2828 Analyzer has been used. In the measured temperature ranges (80 to 480 K, m.p. > 480 K), the structure showed no dielectric anomaly.

Related literature top

For the structure of a related 3,5-dicarboxy-2,6-dimethylpyridinium salt, see: Rowan & Holt (1997). For the ferroelectric properties of supramolecular compounds, see: Ye et al. (2008); Hang et al. (2009). For a description of the Cambridge Structural Database, see: Allen et al. (2002).

Experimental top

2,6-Dimethylpyridine-3,5-dicarboxylic acid (1.95 g , 10 mmol) and concentrated hydrochloric acid (10 mmol) were dissolved in methanol (25 ml). The solution was filtered and left at room temperature for 5 days. Colourless crystals suitable for X-ray analysis were obtained by slow evaporation of the solvent.

Refinement top

The pyridinium and water H atoms were located in a difference Fourier map and refined freely. All other H atoms were calculated geometrically and allowed to ride on their parent atoms, with C—H = 0.93-0.97 Å, O—H = 0.82 Å, and with Uiso(H) = 1.5 Ueq(C, O) or 1.2 Ueq(C) for the aromatic H atom.

Computing details top

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL/PC (Sheldrick, 2008); software used to prepare material for publication: PRPKAPPA (Ferguson, 1999).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. Atoms with suffix A are generated by the symmetry operation (2-x, y, 0.5-z).
[Figure 2] Fig. 2. Crystal packing of the title compound viewed along the b axis. Dashed lines indicate hydrogen bonds.
3,5-Dicarboxy-2,6-dimethylpyridinium chloride dihydrate top
Crystal data top
C9H10NO4+·Cl·2H2OF(000) = 560
Mr = 267.66Dx = 1.458 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 1418 reflections
a = 8.2301 (10) Åθ = 3.3–27.1°
b = 10.7825 (10) ŵ = 0.33 mm1
c = 13.882 (2) ÅT = 293 K
β = 98.11 (3)°Prism, colourless
V = 1219.5 (3) Å30.50 × 0.50 × 0.50 mm
Z = 4
Data collection top
Rigaku Mercury2
diffractometer
1353 independent reflections
Radiation source: fine-focus sealed tube1204 reflections with I > 2σ(I)
graphiteRint = 0.022
Detector resolution: 13.6612 pixels mm-1θmax = 27.1°, θmin = 3.1°
CCD_Profile_fitting scansh = 1010
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
k = 1313
Tmin = 0.938, Tmax = 1.000l = 1717
5826 measured reflections
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)] = 0.044Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.120H atoms treated by a mixture of independent and constrained refinement
S = 1.11 w = 1/[σ2(Fo2) + (0.0618P)2 + 0.5934P]
where P = (Fo2 + 2Fc2)/3
1353 reflections(Δ/σ)max < 0.001
91 parametersΔρmax = 0.26 e Å3
0 restraintsΔρmin = 0.21 e Å3
Crystal data top
C9H10NO4+·Cl·2H2OV = 1219.5 (3) Å3
Mr = 267.66Z = 4
Monoclinic, C2/cMo Kα radiation
a = 8.2301 (10) ŵ = 0.33 mm1
b = 10.7825 (10) ÅT = 293 K
c = 13.882 (2) Å0.50 × 0.50 × 0.50 mm
β = 98.11 (3)°
Data collection top
Rigaku Mercury2
diffractometer
1353 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
1204 reflections with I > 2σ(I)
Tmin = 0.938, Tmax = 1.000Rint = 0.022
5826 measured reflectionsθmax = 27.1°
Refinement top
R[F2 > 2σ(F2)] = 0.044H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.120Δρmax = 0.26 e Å3
S = 1.11Δρmin = 0.21 e Å3
1353 reflectionsAbsolute structure: ?
91 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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
Cl10.00000.47434 (6)0.25000.0491 (2)
O10.80009 (19)0.97343 (12)0.46240 (10)0.0527 (4)
H10.76091.02300.49760.079*
N11.00000.76737 (19)0.25000.0380 (4)
O1W0.8401 (3)0.38706 (18)0.42729 (16)0.0882 (8)
C10.8456 (2)1.03196 (17)0.38880 (13)0.0440 (4)
O20.8329 (2)1.14346 (13)0.37602 (13)0.0691 (5)
C20.9224 (2)0.95307 (16)0.31833 (12)0.0388 (4)
C30.9200 (2)0.82364 (16)0.31650 (12)0.0387 (4)
C40.8353 (3)0.73948 (19)0.37910 (16)0.0569 (5)
H4A0.83620.65630.35450.085*
H4B0.72400.76640.37840.085*
H4C0.89150.74170.44460.085*
C51.00001.0148 (2)0.25000.0395 (5)
H51.00001.10110.25000.047*
H1A1.00000.679 (4)0.25000.066 (9)*
H20.844 (4)0.315 (4)0.422 (2)0.097 (11)*
H2A0.880 (4)0.409 (3)0.380 (3)0.094 (10)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0579 (4)0.0409 (4)0.0525 (4)0.0000.0217 (3)0.000
O10.0749 (9)0.0434 (8)0.0461 (8)0.0062 (6)0.0306 (7)0.0030 (5)
N10.0476 (11)0.0288 (10)0.0412 (11)0.0000.0183 (8)0.000
O1W0.152 (2)0.0408 (9)0.0924 (14)0.0033 (10)0.0889 (15)0.0088 (8)
C10.0525 (10)0.0364 (9)0.0466 (10)0.0028 (7)0.0190 (8)0.0070 (7)
O20.1067 (13)0.0324 (7)0.0792 (11)0.0005 (7)0.0505 (9)0.0073 (7)
C20.0440 (9)0.0346 (8)0.0403 (9)0.0001 (6)0.0149 (7)0.0022 (6)
C30.0455 (9)0.0335 (9)0.0399 (9)0.0003 (6)0.0160 (7)0.0009 (6)
C40.0809 (14)0.0382 (10)0.0607 (12)0.0052 (9)0.0414 (11)0.0003 (8)
C50.0453 (12)0.0294 (11)0.0459 (13)0.0000.0137 (10)0.000
Geometric parameters (Å, °) top
O1—C11.300 (2)C2—C51.386 (2)
O1—H10.8200C2—C31.396 (3)
N1—C31.3513 (18)C3—C41.495 (2)
N1—C3i1.3513 (18)C4—H4A0.9600
N1—H1A0.95 (4)C4—H4B0.9600
O1W—H20.79 (4)C4—H4C0.9600
O1W—H2A0.81 (4)C5—C2i1.386 (2)
C1—O21.218 (2)C5—H50.9300
C1—C21.501 (2)
C1—O1—H1109.5N1—C3—C4115.88 (16)
C3—N1—C3i126.6 (2)C2—C3—C4127.09 (15)
C3—N1—H1A116.68 (10)C3—C4—H4A109.5
C3i—N1—H1A116.68 (11)C3—C4—H4B109.5
H2—O1W—H2A101 (3)H4A—C4—H4B109.5
O2—C1—O1124.43 (16)C3—C4—H4C109.5
O2—C1—C2120.00 (16)H4A—C4—H4C109.5
O1—C1—C2115.55 (16)H4B—C4—H4C109.5
C5—C2—C3118.33 (15)C2i—C5—C2122.6 (2)
C5—C2—C1116.78 (16)C2i—C5—H5118.7
C3—C2—C1124.89 (15)C2—C5—H5118.7
N1—C3—C2117.01 (15)
Symmetry codes: (i) −x+2, y, −z+1/2.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O1Wii0.821.722.537 (2)173
N1—H1A···Cl1iii0.95 (4)2.21 (4)3.160 (2)180 (1)
O1W—H2···O2iv0.79 (4)1.95 (4)2.720 (2)166 (3)
O1W—H2A···Cl1iii0.81 (4)2.29 (4)3.096 (2)177 (3)
Symmetry codes: (ii) −x+3/2, −y+3/2, −z+1; (iii) x+1, y, z; (iv) x, y−1, z.
Table 1
Hydrogen-bond geometry (Å, °)
top
D—H···AD—HH···AD···AD—H···A
O1—H1···O1Wi0.821.722.537 (2)173
N1—H1A···Cl1ii0.95 (4)2.21 (4)3.160 (2)180 (1)
O1W—H2···O2iii0.79 (4)1.95 (4)2.720 (2)166 (3)
O1W—H2A···Cl1ii0.81 (4)2.29 (4)3.096 (2)177 (3)
Symmetry codes: (i) −x+3/2, −y+3/2, −z+1; (ii) x+1, y, z; (iii) x, y−1, z.
Acknowledgements top

The author is grateful to the starter fund of Southeast University for financial support topurchase a single-crystal X-ray diffractometer.

references
References top

Allen, F. H. (2002). Acta Cryst. B58, 380–388.

Ferguson, G. (1999). PRPKAPPA. University of Guelph, Canada.

Hang, T., Fu, D. W., Ye, Q. & Xiong, R. G. (2009). Cryst. Growth Des. 5, 2026–2029.

Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.

Rowan, K. R. & Holt, E. M. (1997). Acta Cryst. C53, 106–108.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Ye, Q., Hang, T., Fu, D. W., Xu, G. H. & Xiong, R. G. (2008). Cryst. Growth Des. 8, 3501–3503.