organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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Oxalic acid–pyridine-4-carbo­nitrile (1/2)

aCollege of Chemistry and Chemical Engineering, Southeast University, Nanjing 210096, People's Republic of China
*Correspondence e-mail: chenxinyuanseu@yahoo.com.cn

(Received 19 April 2012; accepted 28 April 2012; online 5 May 2012)

In the title compound, 2C6H4N2·C2H2O4, the oxalic acid mol­ecule lies about an inversion center. The pyridine ring of the pyridine-4-carbonitrile mol­ecule is almost planar, the largest deviation from the least-squares plane being 0.006 (1) Å; the nitrile N atom deviates from this plane by 0.114 (1) Å. In the crystal, the oxalic acid mol­ecules and the pyridine-4-carbonitrile mol­ecules form stacks. Neighboring mol­ecules within the stacks are related by translation in the a direction, with inter­planar distances of 3.183 (1) and 3.331 (2) Å, respectively. Each oxalic acid mol­ecule forms strong O—H⋯N hydrogen bonds with two mol­ecules of pyridine-4-carbonitrile. Besides this, there are also weak C—H⋯O inter­actions.

Related literature

For the structures and ferroelectric properties of related compounds, see: Fu et al. (2011a[Fu, D.-W., Zhang, W., Cai, H.-L., Zhang, Y., Ge, J.-Z., Xiong, R.-G. & Huang, S. P. D. (2011a). J. Am. Chem. Soc. 133, 12780-12786.],b[Fu, D.-W., Zhang, W., Cai, H.-L., Zhang, Y., Ge, J.-Z., Xiong, R.-G., Huang, S. P. D. & Nakamura, T. (2011b). Angew. Chem. Int. Ed. 50, 11947-11951.],c[Fu, D.-W., Zhang, W., Cai, H.-L., Ge, J.-Z., Zhang, Y. & Xiong, R.-G. (2011c). Adv. Mater. 23, 5658-5662.]); Dai & Chen (2011[Dai, J. & Chen, X.-Y. (2011). Acta Cryst. E67, o287.]); Xu et al. (2011[Xu, R.-J., Fu, D.-W., Dai, J., Zhang, Y., Ge, J.-Z. & Ye, H.-Y. (2011). Inorg. Chem. Commun. 14, 1093-1096.]); Zheng (2011[Zheng, W.-N. (2011). Acta Cryst. E67, m344.]). For standard bond lengths, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]).

[Scheme 1]

Experimental

Crystal data
  • C6H4N2·0.5C2H2O4

  • Mr = 149.13

  • Triclinic, [P \overline 1]

  • a = 3.6842 (6) Å

  • b = 7.5816 (5) Å

  • c = 12.4511 (1) Å

  • α = 78.258 (1)°

  • β = 85.301 (1)°

  • γ = 82.547 (1)°

  • V = 337.08 (6) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.11 mm−1

  • T = 298 K

  • 0.10 × 0.03 × 0.03 mm

Data collection
  • Rigaku SCXmini Mercury2 diffractometer

  • Absorption correction: multi-scan (CrystalClear; Rigaku, 2005[Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.910, Tmax = 1.000

  • 3634 measured reflections

  • 1528 independent reflections

  • 1268 reflections with I > 2σ(I)

  • Rint = 0.024

Refinement
  • R[F2 > 2σ(F2)] = 0.036

  • wR(F2) = 0.101

  • S = 1.04

  • 1528 reflections

  • 103 parameters

  • 1 restraint

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.46 e Å−3

  • Δρmin = −0.27 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H1⋯N1 0.82 (1) 1.80 (1) 2.6173 (12) 176 (2)
C4—H4A⋯O1i 0.93 2.48 3.3640 (13) 160
Symmetry code: (i) x, y+1, z.

Data collection: CrystalClear (Rigaku, 2005[Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.]); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

Simple organic salts containing strong intermolecular H-bonds have attracted an attention as materials which display ferroelectric-paraelectric phase transitions (Fu et al., 2011a,b,c). With the purpose of obtaining crystals of organic salts exhibiting ferroelectric phase transitions, various organic compounds have been studied and the series of new materials have been elaborated (Dai & Chen, 2011; Xu et al., 2011; Zheng, 2011). Herewith we present the synthesis and crystal structure of the title molecular complex, pyridine-4-carbonitrile–oxalic acid (2/1).

All bond lengths and angles in the studied structure have expected values (Allen et al., 1987). The dihedral angle between the pyridine ring and the oxalic acid molecule is 10.29 (8)°. The H atoms of oxalic acid are involved in strong intramolecular O—H···N hydrogen bonds (Fig. 1 and Table 1), with the O···N distance of 2.617 (3)Å. The weak intermolecular C—H···O interaction is also presented in this structure, with C4···O1 = 3.364 (2)Å. The crystal packing is further stabilized by the π···π interactions between the pyridine rings of the neighbouring pyridine-4-carbonitrile molecules (Fig. 2).

Related literature top

For the structures and ferroelectric properties of related compounds, see: Fu et al. (2011a,b,c); Dai & Chen (2011); Xu et al. (2011); Zheng (2011). For standard bond lengths, see: Allen et al. (1987).

Experimental top

The oxalic acid (10 mmol), pyridine-4-carbonitrile (20 mmol) and ethanol (50 mL) were put into a 100mL flask. The mixture was stirred at 60°C for 2 h, and then the precipitate was filtered off. Colourless crystals suitable for X-ray diffraction were obtained by slow evaporation of the solution.

Refinement top

All the H atoms attached to C atoms were placed into the idealized positions and treated as riding with C—H = 0.93 Å and with Uiso(H)=1.2Ueq(C). The positional parameters of the H atom attached to oxygen were refined freely, and at the last stage of the refinement, they were restrained with the H—O = 0.82 (2)Å and with Uiso(H)=1.5Ueq(O).

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 (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. A view of the (2/1) molecular complex with the atomic numbering scheme. The displacement ellipsoids were drawn at the 30% probability level.
[Figure 2] Fig. 2. The crystal packing of the title compound viewed along the a axis and showing the O—H···N, π···π and C—H···O interactions.
Oxalic acid–pyridine-4-carbonitrile (1/2) top
Crystal data top
C6H4N2·0.5C2H2O4Z = 2
Mr = 149.13F(000) = 154
Triclinic, P1Dx = 1.469 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 3.6842 (6) ÅCell parameters from 1528 reflections
b = 7.5816 (5) Åθ = 2.9–27.5°
c = 12.4511 (1) ŵ = 0.11 mm1
α = 78.258 (1)°T = 298 K
β = 85.301 (1)°Block, colourless
γ = 82.547 (1)°0.10 × 0.03 × 0.03 mm
V = 337.08 (6) Å3
Data collection top
Rigaku SCXmini Mercury2
diffractometer
1528 independent reflections
Radiation source: fine-focus sealed tube1268 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.024
Detector resolution: 13.6612 pixels mm-1θmax = 27.5°, θmin = 2.9°
ω scans CCD profile fittingh = 44
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
k = 99
Tmin = 0.910, Tmax = 1.000l = 1616
3634 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)] = 0.036Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.101H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.065P)2]
where P = (Fo2 + 2Fc2)/3
1528 reflections(Δ/σ)max < 0.001
103 parametersΔρmax = 0.46 e Å3
1 restraintΔρmin = 0.27 e Å3
Crystal data top
C6H4N2·0.5C2H2O4γ = 82.547 (1)°
Mr = 149.13V = 337.08 (6) Å3
Triclinic, P1Z = 2
a = 3.6842 (6) ÅMo Kα radiation
b = 7.5816 (5) ŵ = 0.11 mm1
c = 12.4511 (1) ÅT = 298 K
α = 78.258 (1)°0.10 × 0.03 × 0.03 mm
β = 85.301 (1)°
Data collection top
Rigaku SCXmini Mercury2
diffractometer
1528 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
1268 reflections with I > 2σ(I)
Tmin = 0.910, Tmax = 1.000Rint = 0.024
3634 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0361 restraint
wR(F2) = 0.101H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.46 e Å3
1528 reflectionsΔρmin = 0.27 e Å3
103 parameters
Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2sigma(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
O10.8019 (2)0.10266 (10)0.37597 (6)0.0195 (2)
H10.753 (4)0.2095 (6)0.3465 (11)0.029*
O21.0250 (2)0.22804 (10)0.50208 (6)0.0196 (2)
N10.6137 (3)0.43796 (12)0.27800 (8)0.0157 (2)
N20.1419 (3)1.12502 (13)0.09513 (8)0.0207 (2)
C40.5310 (3)0.75440 (15)0.28546 (9)0.0147 (3)
H4A0.55450.84610.32310.018*
C10.4759 (3)0.47781 (15)0.17793 (9)0.0158 (3)
H1A0.45920.38350.14170.019*
C30.3848 (3)0.79346 (14)0.18234 (9)0.0141 (3)
C50.6404 (3)0.57355 (15)0.33014 (9)0.0152 (3)
H5A0.73620.54550.39920.018*
C20.3578 (3)0.65365 (14)0.12654 (9)0.0150 (3)
H2A0.26380.67770.05730.018*
C60.2532 (3)0.97886 (14)0.13355 (9)0.0161 (3)
C70.9557 (3)0.09891 (14)0.46785 (8)0.0140 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0299 (5)0.0114 (4)0.0174 (4)0.0004 (3)0.0102 (4)0.0010 (3)
O20.0269 (5)0.0140 (4)0.0189 (4)0.0026 (3)0.0066 (3)0.0033 (3)
N10.0164 (5)0.0147 (5)0.0158 (5)0.0021 (4)0.0022 (4)0.0020 (4)
N20.0244 (6)0.0171 (5)0.0210 (5)0.0016 (4)0.0067 (4)0.0029 (4)
C40.0142 (5)0.0151 (5)0.0159 (5)0.0027 (4)0.0002 (4)0.0049 (4)
C10.0169 (6)0.0153 (5)0.0164 (5)0.0030 (4)0.0017 (4)0.0048 (4)
C30.0118 (5)0.0130 (5)0.0167 (5)0.0018 (4)0.0004 (4)0.0011 (4)
C50.0157 (5)0.0169 (6)0.0131 (5)0.0027 (4)0.0025 (4)0.0019 (4)
C20.0156 (6)0.0169 (6)0.0126 (5)0.0025 (4)0.0023 (4)0.0024 (4)
C60.0162 (6)0.0177 (6)0.0155 (5)0.0043 (4)0.0014 (4)0.0042 (4)
C70.0144 (5)0.0143 (5)0.0131 (5)0.0010 (4)0.0012 (4)0.0024 (4)
Geometric parameters (Å, º) top
O1—C71.3113 (12)C4—H4A0.9300
O1—H10.822 (2)C1—C21.3871 (15)
O2—C71.2075 (13)C1—H1A0.9300
N1—C51.3403 (14)C3—C21.3981 (15)
N1—C11.3462 (13)C3—C61.4505 (14)
N2—C61.1503 (14)C5—H5A0.9300
C4—C51.3910 (15)C2—H2A0.9300
C4—C31.3940 (14)C7—C7i1.557 (2)
C7—O1—H1107.8 (11)N1—C5—C4122.85 (10)
C5—N1—C1118.83 (9)N1—C5—H5A118.6
C5—C4—C3117.70 (10)C4—C5—H5A118.6
C5—C4—H4A121.1C1—C2—C3117.75 (10)
C3—C4—H4A121.1C1—C2—H2A121.1
N1—C1—C2122.74 (10)C3—C2—H2A121.1
N1—C1—H1A118.6N2—C6—C3178.67 (12)
C2—C1—H1A118.6O2—C7—O1126.63 (10)
C4—C3—C2120.13 (10)O2—C7—C7i121.93 (12)
C4—C3—C6120.12 (9)O1—C7—C7i111.44 (11)
C2—C3—C6119.74 (10)
Symmetry code: (i) x+2, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···N10.82 (1)1.80 (1)2.6173 (12)176 (2)
C4—H4A···O1ii0.932.483.3640 (13)160
Symmetry code: (ii) x, y+1, z.

Experimental details

Crystal data
Chemical formulaC6H4N2·0.5C2H2O4
Mr149.13
Crystal system, space groupTriclinic, P1
Temperature (K)298
a, b, c (Å)3.6842 (6), 7.5816 (5), 12.4511 (1)
α, β, γ (°)78.258 (1), 85.301 (1), 82.547 (1)
V3)337.08 (6)
Z2
Radiation typeMo Kα
µ (mm1)0.11
Crystal size (mm)0.10 × 0.03 × 0.03
Data collection
DiffractometerRigaku SCXmini Mercury2
diffractometer
Absorption correctionMulti-scan
(CrystalClear; Rigaku, 2005)
Tmin, Tmax0.910, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
3634, 1528, 1268
Rint0.024
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.036, 0.101, 1.04
No. of reflections1528
No. of parameters103
No. of restraints1
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.46, 0.27

Computer programs: CrystalClear (Rigaku, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···N10.822 (2)1.797 (3)2.6173 (12)175.5 (15)
C4—H4A···O1i0.932.4803.3640 (13)159.9
Symmetry code: (i) x, y+1, z.
 

Acknowledgements

This work was supported by a start-up grant from Southeast University, China.

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.  CrossRef Web of Science
First citationDai, J. & Chen, X.-Y. (2011). Acta Cryst. E67, o287.  Web of Science CSD CrossRef IUCr Journals
First citationFu, D.-W., Zhang, W., Cai, H.-L., Ge, J.-Z., Zhang, Y. & Xiong, R.-G. (2011c). Adv. Mater. 23, 5658–5662.  Web of Science CSD CrossRef CAS PubMed
First citationFu, D.-W., Zhang, W., Cai, H.-L., Zhang, Y., Ge, J.-Z., Xiong, R.-G. & Huang, S. P. D. (2011a). J. Am. Chem. Soc. 133, 12780–12786.  Web of Science CSD CrossRef CAS PubMed
First citationFu, D.-W., Zhang, W., Cai, H.-L., Zhang, Y., Ge, J.-Z., Xiong, R.-G., Huang, S. P. D. & Nakamura, T. (2011b). Angew. Chem. Int. Ed. 50, 11947–11951.  Web of Science CSD CrossRef CAS
First citationRigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationXu, R.-J., Fu, D.-W., Dai, J., Zhang, Y., Ge, J.-Z. & Ye, H.-Y. (2011). Inorg. Chem. Commun. 14, 1093–1096.  Web of Science CSD CrossRef CAS
First citationZheng, W.-N. (2011). Acta Cryst. E67, m344.  Web of Science CSD CrossRef IUCr Journals

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