Acta Cryst. (2007). E63, m1783-m1784 [ doi:10.1107/S1600536807025536 ]
![[mu]](/logos/entities/mu_rmgif.gif)
3-3-carboxypyrazine-2-carboxylato)]The asymmetric unit of the title compound, [Cs(C6H3N2O4)2(H2O)2]n, contains one CsI cation on an inversion centre, one 3-carboxypyrazine-2-carboxylate anion and one water molecule. In the crystal structure, each anion is linked to three cations, while each cation is surrounded by six of the anions. In addition, each cation is coordinated by two water O atoms, raising the coordination number to ten. In the crystal structure, intermolecular O-H
O and O-HN hydrogen bonds contribute to the stabilization of the structure.
For the preperation of the title compound, (I), Cs2CO3 (882 mg, 2.7 mmol) was carefully added to an aqueous solution (20 ml) containing pyrazine-2,3-di- carboxylic acid (1680 mg, 10 mmol) and B(OH)3 (5 mmol, 0.31 g), until no bubbles escapes. The reaction mixture produced a colorless and clear solution, which was stirred at 333 K for 5 h, until all became solid. The solid product was redissolved in water (10 ml) and allowed to stand for 10 min at room temperature, whereupon transparent and fine crystals were harvested.
The pyrazine H atoms were positioned geometrically with C—H = 0.94 Å and constrained to ride on their parent atoms, with Uiso(H) = 1.2Ueq(C). H atoms of carboxylate and water molecules were located in difference syntheses and refined isotropically [O—H = 0.64 (4)–0.83 (4) Å and Uiso(H) = 0.057 (9)–0.066 (9) Å2].
Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2001); software used to prepare material for publication: enCIFer (Allen et al., 2004).
![[Figure 1]](./hk2251fig1thm.gif)
| Fig. 1. A segment of the structure of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level [symmetry codes: (i) 2 - x, -1 - y, 1 - z, (ii) 1 + x, y, z, (iii) 2 - x, -y, 1 - z, (iv) 1 + x, -1 + y, z, (v) 3 - x, -1 - y, 1 - z]. |
![[Figure 2]](./hk2251fig2thm.gif)
| Fig. 2. A packing diagram for (I). The hydrogen bonds are shown as dashed lines [(1) O3—H(4)..N2, (2) O3—H5..O1, (3) O5—H3..O3]. |
| [Cs(C6H3N2O4)2(H2O)2] | Z = 1 |
| Mr = 503.15 | F(000) = 245 |
| Triclinic, P1 | Dx = 1.968 Mg m−3 |
| Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
| a = 7.4801 (9) Å | Cell parameters from 22636 reflections |
| b = 7.6352 (9) Å | θ = 2.5–28.0° |
| c = 8.6505 (11) Å | µ = 2.24 mm−1 |
| α = 70.031 (9)° | T = 296 K |
| β = 81.126 (10)° | Prism, colorless |
| γ = 66.128 (9)° | 0.52 × 0.47 × 0.42 mm |
| V = 424.55 (10) Å3 |
| Stoe IPDS2 diffractometer | 1968 independent reflections |
| Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus | 1949 reflections with I > 2σ(I) |
| Plane graphite monochromator | Rint = 0.057 |
| Detector resolution: 6.67 pixels mm-1 | θmax = 27.7°, θmin = 2.5° |
| rotation method scans | h = −9→9 |
| Absorption correction: integration (X-RED32; Stoe & Cie, 2002) | k = −9→9 |
| Tmin = 0.382, Tmax = 0.471 | l = −11→11 |
| 7683 measured reflections |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.019 | H atoms treated by a mixture of independent and constrained refinement |
| wR(F2) = 0.052 | w = 1/[σ2(Fo2) + (0.0343P)2 + 0.0717P] where P = (Fo2 + 2Fc2)/3 |
| S = 0.98 | (Δ/σ)max < 0.001 |
| 1968 reflections | Δρmax = 0.45 e Å−3 |
| 137 parameters | Δρmin = −0.71 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: 0.187 (6) |
| [Cs(C6H3N2O4)2(H2O)2] | γ = 66.128 (9)° |
| Mr = 503.15 | V = 424.55 (10) Å3 |
| Triclinic, P1 | Z = 1 |
| a = 7.4801 (9) Å | Mo Kα radiation |
| b = 7.6352 (9) Å | µ = 2.24 mm−1 |
| c = 8.6505 (11) Å | T = 296 K |
| α = 70.031 (9)° | 0.52 × 0.47 × 0.42 mm |
| β = 81.126 (10)° |
| Stoe IPDS2 diffractometer | 1968 independent reflections |
| Absorption correction: integration (X-RED32; Stoe & Cie, 2002) | 1949 reflections with I > 2σ(I) |
| Tmin = 0.382, Tmax = 0.471 | Rint = 0.057 |
| 7683 measured reflections | θmax = 27.7° |
| R[F2 > 2σ(F2)] = 0.019 | H atoms treated by a mixture of independent and constrained refinement |
| wR(F2) = 0.052 | Δρmax = 0.45 e Å−3 |
| S = 0.98 | Δρmin = −0.71 e Å−3 |
| 1968 reflections | Absolute structure: ? |
| 137 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
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. |
| x | y | z | Uiso*/Ueq | ||
| Cs1 | 1.5000 | −0.5000 | 0.5000 | 0.04315 (10) | |
| O1 | 0.7652 (2) | −0.1628 (2) | 0.3351 (2) | 0.0447 (3) | |
| O2 | 0.54073 (19) | 0.3193 (2) | 0.2006 (2) | 0.0464 (3) | |
| O3 | 1.6315 (3) | −0.2774 (3) | 0.1162 (2) | 0.0545 (4) | |
| H4 | 1.719 (5) | −0.381 (6) | 0.118 (4) | 0.059 (8)* | |
| H5 | 1.659 (5) | −0.228 (6) | 0.147 (4) | 0.057 (9)* | |
| O4 | 1.0625 (2) | −0.3669 (2) | 0.4303 (2) | 0.0500 (4) | |
| O5 | 0.6999 (2) | 0.1627 (3) | 0.0154 (2) | 0.0507 (3) | |
| H3 | 0.589 (5) | 0.202 (6) | −0.020 (5) | 0.066 (9)* | |
| N1 | 1.1830 (2) | −0.0606 (2) | 0.34310 (19) | 0.0342 (3) | |
| N2 | 0.9390 (2) | 0.3245 (2) | 0.1696 (2) | 0.0378 (3) | |
| C1 | 1.2381 (2) | 0.0943 (3) | 0.3004 (2) | 0.0376 (3) | |
| H1 | 1.3639 | 0.0727 | 0.3275 | 0.045* | |
| C2 | 1.1156 (3) | 0.2872 (3) | 0.2169 (3) | 0.0403 (4) | |
| H2 | 1.1579 | 0.3942 | 0.1930 | 0.048* | |
| C3 | 0.8866 (2) | 0.1668 (2) | 0.20647 (19) | 0.0297 (3) | |
| C4 | 1.0056 (2) | −0.0248 (2) | 0.29693 (19) | 0.0286 (3) | |
| C5 | 0.6880 (2) | 0.2210 (2) | 0.1433 (2) | 0.0331 (3) | |
| C6 | 0.9360 (2) | −0.1975 (3) | 0.3563 (2) | 0.0332 (3) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Cs1 | 0.03439 (11) | 0.03736 (11) | 0.04492 (12) | −0.00218 (7) | −0.00804 (6) | −0.00818 (7) |
| O1 | 0.0369 (6) | 0.0391 (7) | 0.0612 (8) | −0.0182 (6) | −0.0151 (6) | −0.0086 (6) |
| O2 | 0.0287 (6) | 0.0499 (8) | 0.0663 (9) | −0.0114 (6) | −0.0034 (6) | −0.0280 (7) |
| O3 | 0.0501 (8) | 0.0445 (8) | 0.0754 (11) | −0.0075 (7) | −0.0265 (8) | −0.0279 (8) |
| O4 | 0.0350 (6) | 0.0290 (6) | 0.0762 (10) | −0.0138 (5) | −0.0103 (7) | 0.0014 (6) |
| O5 | 0.0401 (7) | 0.0623 (9) | 0.0481 (7) | −0.0066 (7) | −0.0147 (6) | −0.0247 (7) |
| N1 | 0.0282 (6) | 0.0320 (6) | 0.0403 (7) | −0.0109 (5) | −0.0050 (5) | −0.0073 (6) |
| N2 | 0.0341 (7) | 0.0291 (6) | 0.0481 (8) | −0.0135 (6) | −0.0073 (6) | −0.0049 (6) |
| C1 | 0.0286 (7) | 0.0393 (9) | 0.0472 (9) | −0.0163 (7) | −0.0045 (7) | −0.0101 (7) |
| C2 | 0.0349 (8) | 0.0347 (8) | 0.0539 (10) | −0.0185 (7) | −0.0047 (7) | −0.0084 (7) |
| C3 | 0.0275 (7) | 0.0299 (7) | 0.0315 (6) | −0.0110 (6) | −0.0027 (6) | −0.0083 (6) |
| C4 | 0.0277 (6) | 0.0282 (7) | 0.0310 (6) | −0.0116 (6) | −0.0018 (6) | −0.0088 (5) |
| C5 | 0.0305 (7) | 0.0286 (7) | 0.0394 (8) | −0.0109 (6) | −0.0069 (6) | −0.0073 (6) |
| C6 | 0.0338 (7) | 0.0299 (7) | 0.0378 (7) | −0.0145 (6) | −0.0042 (6) | −0.0084 (6) |
| Cs1—O1i | 3.188 (2) | O4—C6 | 1.268 (2) |
| Cs1—O1ii | 3.188 (2) | O5—C5 | 1.305 (2) |
| Cs1—O2iii | 3.249 (1) | O5—H3 | 0.83 (4) |
| Cs1—O2iv | 3.249 (2) | N1—C1 | 1.325 (2) |
| Cs1—O3 | 3.372 (2) | N1—C4 | 1.338 (2) |
| Cs1—O3i | 3.372 (2) | N2—C2 | 1.333 (2) |
| Cs1—O4 | 3.099 (1) | N2—C3 | 1.336 (2) |
| Cs1—O4i | 3.099 (1) | C1—C2 | 1.384 (3) |
| Cs1—N1 | 3.188 (2) | C1—H1 | 0.9400 |
| Cs1—N1i | 3.188 (2) | C2—H2 | 0.9400 |
| O1—C6 | 1.226 (2) | C4—C3 | 1.387 (2) |
| O2—C5 | 1.200 (2) | C5—C3 | 1.509 (2) |
| O3—H4 | 0.79 (4) | C6—C4 | 1.511 (2) |
| O3—H5 | 0.64 (4) | ||
| H4—O3—H5 | 109 (4) | N2—C3—C5 | 113.30 (14) |
| C5—O5—H3 | 109 (2) | C4—C3—C5 | 124.88 (13) |
| C1—N1—C4 | 117.24 (15) | N1—C4—C3 | 120.82 (14) |
| C2—N2—C3 | 116.75 (15) | N1—C4—C6 | 117.40 (15) |
| N1—C1—C2 | 121.84 (15) | C3—C4—C6 | 121.66 (14) |
| N1—C1—H1 | 119.1 | O2—C5—O5 | 125.96 (17) |
| C2—C1—H1 | 119.1 | O2—C5—C3 | 121.64 (15) |
| N2—C2—C1 | 121.40 (15) | O5—C5—C3 | 112.19 (14) |
| N2—C2—H2 | 119.3 | O1—C6—O4 | 126.00 (15) |
| C1—C2—H2 | 119.3 | O1—C6—C4 | 118.73 (16) |
| N2—C3—C4 | 121.81 (14) | O4—C6—C4 | 115.22 (14) |
| C4—N1—C1—C2 | 2.4 (3) | C6—C4—C3—C5 | −6.3 (2) |
| C1—N1—C4—C3 | 0.7 (2) | O2—C5—C3—N2 | −69.7 (2) |
| C1—N1—C4—C6 | −175.48 (15) | O5—C5—C3—N2 | 105.33 (18) |
| C3—N2—C2—C1 | −0.1 (3) | O2—C5—C3—C4 | 109.1 (2) |
| C2—N2—C3—C4 | 3.2 (2) | O5—C5—C3—C4 | −75.9 (2) |
| C2—N2—C3—C5 | −177.92 (16) | O1—C6—C4—N1 | 170.21 (16) |
| N1—C1—C2—N2 | −2.8 (3) | O4—C6—C4—N1 | −7.3 (2) |
| N1—C4—C3—N2 | −3.7 (2) | O1—C6—C4—C3 | −6.0 (2) |
| C6—C4—C3—N2 | 172.36 (15) | O4—C6—C4—C3 | 176.54 (16) |
| N1—C4—C3—C5 | 177.61 (15) |
| Symmetry codes: (i) −x+1, −y−1, −z+1; (ii) x+1, y, z; (iii) x+1, y−1, z; (iv) −x, −y, −z+1. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O5—H3···O3v | 0.83 (1) | 1.76 (1) | 2.577 (1) | 172.70 (3) |
| O3—H4···N2iii | 0.79 (1) | 2.13 (1) | 2.907 (1) | 169.64 (3) |
| O3—H5···O1ii | 0.64 (1) | 2.19 (1) | 2.788 (1) | 157.14 (3) |
| Symmetry codes: (ii) x+1, y, z; (iii) x+1, y−1, z; (v) −x, −y, −z. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O5—H3···O3i | 0.83 (1) | 1.76 (1) | 2.577 (1) | 172.70 (3) |
| O3—H4···N2ii | 0.79 (1) | 2.13 (1) | 2.907 (1) | 169.64 (3) |
| O3—H5···O1iii | 0.64 (1) | 2.19 (1) | 2.788 (1) | 157.14 (3) |
| Symmetry codes: (i) −x, −y, −z; (ii) x+1, y−1, z; (iii) x+1, y, z. |
The authors wish to acknowledge the Faculty of Art and Science, Kirikkale University for financial support and the Faculty of Art and Science, Ondokuz Mayis University, Turkey, for use of the Stoe IPDS II diffractometer (purchased under grant F.279 of the University Research Fund).
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Metal dicarboxylates are known to form structures with varying dimensionalities, e.g. chains or layers, linked by the dicarboxylate anions (Rao et al., 2004). Since the single-crystal X-ray analysis of pyrazine-2,3 dicarboxylic acid was first determined (Takusagawa & Shimada, 1973), a variety of metal-organic compounds of pyrazine-2,3-dicarboxylic acid have been characterized crystallographically, due to growing interest in supramolecular chemistry. These include the calcium (Ptasiewicz-Bak & Leciejewicz, 1997a; Starosta & Leciejewicz, 2005) and magnesium (Ptasiewicz-Bak & Leciejewicz, 1997b) complexes. The title compound (I), was obtained as a colorless powder during an attempt to synthesize a borate ester product from the reaction of Cs2CO3 with B(OH)3 and pyrazine-2,3-dicarboxylic acid, akin to the result for the sodium complex reported previously by our group (Tombul et al., 2006). We herein report its crystal structure.
The asymmetric unit of the title compound, (I), contains one caesium cation, one pyrazine-2,3-dicarboxylate anion and one water molecule (Fig. 1). The pyrazine-2,3-dicarboxylic acid is deprotonated at one of the carboxylate groups so that the crystal structure consists of Cs+ cations and pyrazine-2,3-dicarboxylate anions. Taking a larger domain of the crystal structure, the anion is linked to three cations, while the cation is surrounded by six of the anions, two of which are coordinated by N and O atoms and the remaining four anions are coordinated solely by O atoms. In addition, each caesium atom is coordinated by two water molecules, reaching the coordination number to ten. The inner coordination sphere accommodates eight oxygen atoms (O3, O4, O1i, O1ii, O3iii, O2iv, O4iv and O3v), together with two nitrogen atoms (N1 and N1i) [Symmetry Codes: (i) 2 - x, -1 - y, 1 - z, (ii) 1 + x, y, z, (iii) 2 - x, -y, 1 - z, (iv) 1 + x, -1 + y, z, (v) 3 - x, -1 - y, 1 - z]. The Cs—O distances are in the range of 3.099 (1)–3.372 (2) Å, in which they are in accordance with the corresponding values reported for other caesium complexes (Harnish et al., 1999; Wiesbrock & Schmidbaur, 2003; Hu et al., 2005).
In the crystal structure, the intermolecular O—H···O and O—H···N hydrogen bonds (Table 2, Fig. 2) may be effective in the stabilization of the structure.