supplementary materials


jj2111 scheme

Acta Cryst. (2012). E68, o132    [ doi:10.1107/S1600536811052366 ]

5,6-Dimethylpyrazine-2,3-dicarboxylic acid

F.-H. Liu

Abstract top

The asymmetric unit of the title compound, C8H8N2O4, consists of one complete molecule and a second molecule generated by the application of twofold axis. The mean planes of the two carboxyl groups attached to the pyrazine ring at neighboring positions are twisted by 10.8 (1) and 87.9 (1)° in the complete molecule and 43.0 (1)° in the symmetry-generated molecule. The crystal packing features O-H...N hydrogen bonds, which link the molecules into layers along [101].

Comment top

2,3-dicarboxypyrazine-based ligands are well suited for the building of large clusters. With two carboxyl groups available for binding and a non-binding site opposite, selective interactions with metal ions are common. For example, a Co36 cluster using a pyrazine-2,3-dicarboxylic acid ligand similar to the title compound has been reported (Alborés & Rentschler, 2009) Similarly, the crystal structure of the title compound containing one water molecule in the unit cell has also been reported (Vishweshwar et al., 2001; Vishweshwar et al., 2004), In view of the importance of compounds containing this ligand we report herin the crystal structure of the title compound, (I).

The asymmetric unit of the title compound, C8H8N2O4, consists of one molecule and a second complete molecule generated by the application of a centre of inversion (Fig. 1). For each molecule, the mean planes of the two carboxyl groups attached to the pyrazine ring at neighboring positionsare twisted by 10.8 (1)° and 87.9 (3)°. Crystal packing is stabilized by O—H···N hydrogen bonds which link the molecules into layers along [101] (Fig. 2).

Related literature top

For the synthesis of the title compound, see Tsuda & Fujishima (1981). For the structure of the hydrate of the title compound, see Vishweshwar et al. (2001, 2004). For a related compound containing a similar pyrazine-2,3-dicarboxylic acid ligand, see: Alborés & Rentschler (2009).

Experimental top

The compound was synthesized by a reported reaction (Tsuda & Fujishima, 1981) and crystallized by a solvent-thermal reaction as follows: 196.16 mg (1 mmol) C8H8N2O4 and 10 mlN, N-dimethylformamide (DMF) was added to a 20 ml Teflon vessel. The vessel was sealed and placed inside a stainless steel autoclave, which was kept at 130°C for 72 h. Crystals suitable for single-crystal analysis were formed upon standing.

Refinement top

H atoms bonded to O atom were located in a Fourier difference map and refined with distance restraints of O—H = 0.820 Å, and with Uiso(H) = 1.5Ueq(O). The remaining H atoms were positioned geometrically and refined using the riding model, with C—H = 0.960 Å and with Uiso(H) = 1.5 times Ueq(C).

Computing details top

Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO (Rigaku, 1998); data reduction: CrystalStructure (Rigaku/MSC, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. Molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. Packing view of (I). (a) View of layers in (I) along the b axis. (b) View of the title compound along the a axis. Dashed lines indicate O—H···N hydrogen bonds. H atoms not involved in hydrogen bonds have been deleted for clarity.
5,6-Dimethylpyrazine-2,3-dicarboxylic acid top
Crystal data top
C8H8N2O4F(000) = 1224
Mr = 196.16Dx = 1.547 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 10631 reflections
a = 15.873 (3) Åθ = 3.4–27.8°
b = 14.057 (3) ŵ = 0.13 mm1
c = 11.991 (2) ÅT = 293 K
β = 109.21 (3)°Block, colourless
V = 2526.6 (9) Å30.30 × 0.25 × 0.20 mm
Z = 12
Data collection top
Rigaku SCX-mini
diffractometer
1937 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.043
graphiteθmax = 25.0°, θmin = 3.4°
ω scansh = 1818
10832 measured reflectionsk = 1616
2230 independent reflectionsl = 1414
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)] = 0.049Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.133H-atom parameters constrained
S = 1.07 w = 1/[σ2(Fo2) + (0.0617P)2 + 3.0039P]
where P = (Fo2 + 2Fc2)/3
2230 reflections(Δ/σ)max < 0.001
196 parametersΔρmax = 0.63 e Å3
0 restraintsΔρmin = 0.39 e Å3
Crystal data top
C8H8N2O4V = 2526.6 (9) Å3
Mr = 196.16Z = 12
Monoclinic, C2/cMo Kα radiation
a = 15.873 (3) ŵ = 0.13 mm1
b = 14.057 (3) ÅT = 293 K
c = 11.991 (2) Å0.30 × 0.25 × 0.20 mm
β = 109.21 (3)°
Data collection top
Rigaku SCX-mini
diffractometer
Rint = 0.043
10832 measured reflectionsθmax = 25.0°
2230 independent reflectionsStandard reflections: 0
1937 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.049H-atom parameters constrained
wR(F2) = 0.133Δρmax = 0.63 e Å3
S = 1.07Δρmin = 0.39 e Å3
2230 reflectionsAbsolute structure: ?
196 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
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
O10.28005 (14)0.38972 (11)0.78999 (16)0.0595 (6)
H10.25870.34680.74280.089*
O20.17345 (15)0.47314 (13)0.66739 (18)0.0745 (7)
O30.20112 (11)0.67092 (14)0.57803 (14)0.0482 (5)
H30.15910.68470.51900.072*
O40.09881 (12)0.67291 (15)0.66709 (16)0.0567 (5)
O50.40546 (13)0.35937 (12)0.02848 (13)0.0474 (5)
H50.38150.41010.00260.071*
O60.40159 (11)0.41517 (11)0.20060 (15)0.0439 (4)
N10.34098 (12)0.54156 (12)0.92729 (14)0.0318 (4)
N20.28289 (12)0.72021 (12)0.84036 (15)0.0325 (4)
N30.43566 (12)0.18493 (12)0.14017 (14)0.0311 (4)
C10.23855 (16)0.46795 (15)0.75119 (19)0.0362 (5)
C20.27656 (14)0.55308 (14)0.82342 (17)0.0291 (5)
C30.37616 (14)0.61868 (15)0.98780 (18)0.0325 (5)
C40.44770 (18)0.60708 (18)1.1037 (2)0.0491 (7)
H4A0.42310.61601.16620.074*
H4B0.49360.65341.11100.074*
H4C0.47260.54441.10900.074*
C50.17291 (15)0.66150 (14)0.66717 (19)0.0324 (5)
C60.24752 (13)0.64193 (14)0.78045 (17)0.0276 (5)
C70.34688 (14)0.70945 (15)0.94401 (18)0.0315 (5)
C80.38542 (18)0.79617 (17)1.0119 (2)0.0489 (7)
H8A0.44580.80401.01320.073*
H8B0.38460.79001.09130.073*
H8C0.35080.85060.97520.073*
C90.42126 (14)0.35590 (15)0.14246 (18)0.0316 (5)
C100.46645 (14)0.26613 (14)0.19620 (17)0.0286 (5)
C110.46841 (15)0.10400 (15)0.19300 (18)0.0315 (5)
C120.43794 (18)0.01403 (16)0.1277 (2)0.0462 (6)
H12A0.38700.02640.05930.069*
H12B0.42200.03060.17800.069*
H12C0.48510.01200.10360.069*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0717 (13)0.0232 (8)0.0508 (11)0.0069 (8)0.0244 (9)0.0016 (7)
O20.0871 (15)0.0368 (10)0.0546 (12)0.0090 (10)0.0375 (11)0.0110 (9)
O30.0448 (10)0.0646 (12)0.0236 (8)0.0094 (9)0.0042 (7)0.0075 (8)
O40.0354 (10)0.0753 (14)0.0467 (11)0.0054 (9)0.0037 (8)0.0138 (9)
O50.0688 (12)0.0361 (9)0.0240 (8)0.0145 (9)0.0028 (8)0.0065 (7)
O60.0525 (11)0.0343 (9)0.0447 (10)0.0100 (8)0.0157 (8)0.0008 (7)
N10.0353 (10)0.0277 (9)0.0221 (9)0.0014 (8)0.0044 (8)0.0045 (7)
N20.0346 (10)0.0269 (9)0.0257 (9)0.0005 (8)0.0040 (8)0.0010 (7)
N30.0375 (10)0.0278 (9)0.0201 (9)0.0013 (8)0.0014 (7)0.0005 (7)
C10.0447 (13)0.0259 (11)0.0258 (11)0.0001 (10)0.0049 (10)0.0017 (9)
C20.0313 (11)0.0263 (11)0.0223 (10)0.0008 (9)0.0011 (8)0.0021 (8)
C30.0344 (12)0.0310 (11)0.0232 (11)0.0061 (9)0.0027 (9)0.0032 (8)
C40.0528 (16)0.0414 (13)0.0319 (13)0.0110 (12)0.0148 (11)0.0073 (10)
C50.0341 (13)0.0226 (11)0.0295 (12)0.0000 (9)0.0042 (9)0.0024 (8)
C60.0291 (11)0.0241 (10)0.0226 (10)0.0021 (9)0.0011 (8)0.0004 (8)
C70.0340 (12)0.0298 (11)0.0229 (11)0.0052 (9)0.0012 (9)0.0002 (8)
C80.0577 (16)0.0324 (13)0.0369 (14)0.0090 (11)0.0111 (12)0.0027 (10)
C90.0312 (11)0.0287 (11)0.0275 (11)0.0012 (9)0.0006 (9)0.0019 (9)
C100.0339 (11)0.0263 (11)0.0210 (10)0.0003 (9)0.0026 (8)0.0011 (8)
C110.0392 (12)0.0260 (11)0.0239 (11)0.0021 (9)0.0027 (9)0.0010 (8)
C120.0618 (16)0.0295 (12)0.0338 (13)0.0040 (11)0.0025 (11)0.0054 (10)
Geometric parameters (Å, °) top
O1—C11.288 (3)C3—C71.400 (3)
O1—H10.8200C3—C41.487 (3)
O2—C11.183 (3)C4—H4A0.9600
O3—C51.294 (3)C4—H4B0.9600
O3—H30.8200C4—H4C0.9600
O4—C51.187 (3)C5—C61.505 (3)
O5—C91.307 (3)C7—C81.482 (3)
O5—H50.8200C8—H8A0.9600
O6—C91.192 (3)C8—H8B0.9600
N1—C31.322 (3)C8—H8C0.9600
N1—C21.336 (3)C9—C101.489 (3)
N2—C71.330 (3)C10—C10i1.377 (4)
N2—C61.333 (3)C11—C11i1.405 (4)
N3—C111.323 (3)C11—C121.482 (3)
N3—C101.333 (3)C12—H12A0.9600
C1—C21.484 (3)C12—H12B0.9600
C2—C61.372 (3)C12—H12C0.9600
C1—O1—H1109.5C2—C6—C5124.95 (18)
C5—O3—H3109.5N2—C7—C3120.76 (18)
C9—O5—H5109.5N2—C7—C8118.06 (19)
C3—N1—C2117.91 (17)C3—C7—C8121.17 (19)
C7—N2—C6117.82 (18)C7—C8—H8A109.5
C11—N3—C10118.29 (17)C7—C8—H8B109.5
O2—C1—O1124.0 (2)H8A—C8—H8B109.5
O2—C1—C2121.3 (2)C7—C8—H8C109.5
O1—C1—C2114.60 (18)H8A—C8—H8C109.5
N1—C2—C6121.33 (18)H8B—C8—H8C109.5
N1—C2—C1119.07 (18)O6—C9—O5126.0 (2)
C6—C2—C1119.54 (18)O6—C9—C10121.38 (19)
N1—C3—C7120.89 (18)O5—C9—C10112.56 (19)
N1—C3—C4118.57 (19)N3—C10—C10i120.98 (11)
C7—C3—C4120.54 (19)N3—C10—C9117.57 (18)
C3—C4—H4A109.5C10i—C10—C9121.30 (11)
C3—C4—H4B109.5N3—C11—C11i120.57 (11)
H4A—C4—H4B109.5N3—C11—C12118.19 (19)
C3—C4—H4C109.5C11i—C11—C12121.23 (13)
H4A—C4—H4C109.5C11—C12—H12A109.5
H4B—C4—H4C109.5C11—C12—H12B109.5
O4—C5—O3126.7 (2)H12A—C12—H12B109.5
O4—C5—C6120.7 (2)C11—C12—H12C109.5
O3—C5—C6112.4 (2)H12A—C12—H12C109.5
N2—C6—C2121.28 (18)H12B—C12—H12C109.5
N2—C6—C5113.73 (17)
C3—N1—C2—C60.0 (3)O4—C5—C6—C293.3 (3)
C3—N1—C2—C1177.4 (2)O3—C5—C6—C291.5 (3)
O2—C1—C2—N1169.2 (3)C6—N2—C7—C30.4 (3)
O1—C1—C2—N18.3 (3)C6—N2—C7—C8179.0 (2)
O2—C1—C2—C613.3 (4)N1—C3—C7—N20.0 (3)
O1—C1—C2—C6169.1 (2)C4—C3—C7—N2180.0 (2)
C2—N1—C3—C70.2 (3)N1—C3—C7—C8179.4 (2)
C2—N1—C3—C4179.8 (2)C4—C3—C7—C80.6 (4)
C7—N2—C6—C20.6 (3)C11—N3—C10—C10i3.0 (4)
C7—N2—C6—C5177.3 (2)C11—N3—C10—C9172.7 (2)
N1—C2—C6—N20.5 (3)O6—C9—C10—N3134.4 (2)
C1—C2—C6—N2177.0 (2)O5—C9—C10—N344.4 (3)
N1—C2—C6—C5177.3 (2)O6—C9—C10—C10i41.3 (4)
C1—C2—C6—C55.3 (3)O5—C9—C10—C10i140.0 (3)
O4—C5—C6—N284.5 (3)C10—N3—C11—C11i2.3 (4)
O3—C5—C6—N290.6 (2)C10—N3—C11—C12176.5 (2)
Symmetry codes: (i) −x+1, y, −z+1/2.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O1—H1···N2ii0.82 (1)2.042.845 (2)167.
O3—H3···N3iii0.82 (1)2.002.803 (2)165.
O5—H5···N1iv0.82 (1)2.062.874 (2)169.
Symmetry codes: (ii) −x+1/2, y−1/2, −z+3/2; (iii) −x+1/2, y+1/2, −z+1/2; (iv) x, y, z−1.
Table 1
Hydrogen-bond geometry (Å, °)
top
D—H···AD—HH···AD···AD—H···A
O1—H1···N2i0.82 (1)2.042.845 (2)167.
O3—H3···N3ii0.82 (1)2.002.803 (2)165.
O5—H5···N1iii0.82 (1)2.062.874 (2)169.
Symmetry codes: (i) −x+1/2, y−1/2, −z+3/2; (ii) −x+1/2, y+1/2, −z+1/2; (iii) x, y, z−1.
Acknowledgements top

The author thanks the Jilin Business and Technology College for financial support.

references
References top

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