Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536803006883/cf6249sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536803006883/cf6249Isup2.hkl |
CCDC reference: 209905
5 ml of a stirred aqueous solution of pyrazine-2,3-dicarboxylic acid (84 mg, 0.5 mmol) was adjusted to pH ca 7 with 1 N NaOH aqueous solution, then KSCN (49 mg, 0.5 mmol) was added. After complete dissolution, Cu(NO3)2·3H2O (60 mg, 0.25 mmol) was added, giving a clear blue solution, which was filtered. Upon evaporation in air, blue prismatic crystals were obtained in a few days (yield 58%).
H atoms were positioned geometrically and refined as riding on their parent atoms; no H atoms were included for the water molecules.
Data collection: SMART (Siemens, 1996); cell refinement: SMART and SAINT (Siemens, 1994); data reduction: SAINT and SHELXTL (Siemens, 1994); program(s) used to solve structure: SHELXTL; program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
Na2K2[Cu(C6H2N2O4)2](SCN)2·2H2O | F(000) = 670 |
Mr = 672.10 | Dx = 2.021 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 6.8349 (7) Å | Cell parameters from 2150 reflections |
b = 6.9692 (7) Å | θ = 1.8–25.0° |
c = 23.184 (2) Å | µ = 1.66 mm−1 |
β = 90.797 (2)° | T = 293 K |
V = 1104.23 (19) Å3 | Prism, blue |
Z = 2 | 0.68 × 0.22 × 0.18 mm |
Siemens SMART CCD diffractometer | 1929 independent reflections |
Radiation source: fine-focus sealed tube | 1663 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.025 |
ω scans | θmax = 25.0°, θmin = 1.8° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −8→8 |
Tmin = 0.514, Tmax = 0.741 | k = −6→8 |
3306 measured reflections | l = −27→9 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.040 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.106 | H-atom parameters constrained |
S = 1.00 | w = 1/[σ2(Fo2) + (0.0473P)2 + 3.7091P] where P = (Fo2 + 2Fc2)/3 |
1929 reflections | (Δ/σ)max < 0.001 |
169 parameters | Δρmax = 0.50 e Å−3 |
0 restraints | Δρmin = −0.64 e Å−3 |
Na2K2[Cu(C6H2N2O4)2](SCN)2·2H2O | V = 1104.23 (19) Å3 |
Mr = 672.10 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 6.8349 (7) Å | µ = 1.66 mm−1 |
b = 6.9692 (7) Å | T = 293 K |
c = 23.184 (2) Å | 0.68 × 0.22 × 0.18 mm |
β = 90.797 (2)° |
Siemens SMART CCD diffractometer | 1929 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1663 reflections with I > 2σ(I) |
Tmin = 0.514, Tmax = 0.741 | Rint = 0.025 |
3306 measured reflections |
R[F2 > 2σ(F2)] = 0.040 | 0 restraints |
wR(F2) = 0.106 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.50 e Å−3 |
1929 reflections | Δρmin = −0.64 e Å−3 |
169 parameters |
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 | ||
Cu1 | 0.5000 | 0.5000 | 0.0000 | 0.0253 (2) | |
K1 | 0.66535 (14) | 0.29284 (15) | 0.24276 (4) | 0.0368 (3) | |
Na1 | 0.1562 (2) | 0.3776 (3) | 0.18520 (7) | 0.0342 (4) | |
S1 | −0.39800 (14) | 0.12607 (14) | 0.05177 (4) | 0.0278 (3) | |
C1 | −0.2341 (6) | 0.2114 (5) | 0.09809 (17) | 0.0253 (8) | |
C2 | 0.8786 (5) | 0.7055 (6) | 0.01637 (16) | 0.0252 (8) | |
H1A | 0.8993 | 0.6934 | −0.0230 | 0.030* | |
C3 | 1.0162 (6) | 0.7956 (6) | 0.05106 (16) | 0.0265 (9) | |
H2A | 1.1272 | 0.8466 | 0.0341 | 0.032* | |
C4 | 0.8302 (5) | 0.7439 (5) | 0.13118 (15) | 0.0185 (7) | |
C5 | 0.6869 (5) | 0.6576 (5) | 0.09638 (15) | 0.0184 (7) | |
C6 | 0.4927 (5) | 0.5771 (5) | 0.11627 (15) | 0.0196 (7) | |
C7 | 0.8251 (5) | 0.7633 (6) | 0.19643 (16) | 0.0230 (8) | |
N1 | −0.1189 (5) | 0.2741 (5) | 0.13020 (16) | 0.0371 (9) | |
N2 | 0.9962 (4) | 0.8122 (5) | 0.10792 (13) | 0.0238 (7) | |
N3 | 0.7161 (4) | 0.6362 (4) | 0.03943 (12) | 0.0195 (6) | |
O1 | 0.9468 (4) | 0.6603 (5) | 0.22316 (12) | 0.0368 (7) | |
O2 | 0.7119 (4) | 0.8837 (4) | 0.21772 (11) | 0.0302 (6) | |
O3 | 0.3746 (4) | 0.5306 (4) | 0.07552 (11) | 0.0259 (6) | |
O4 | 0.4600 (4) | 0.5583 (4) | 0.16829 (11) | 0.0256 (6) | |
O1W | 0.2985 (4) | 0.0653 (5) | 0.16246 (14) | 0.0436 (8) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cu1 | 0.0224 (3) | 0.0366 (4) | 0.0170 (3) | −0.0021 (3) | 0.0017 (2) | −0.0092 (3) |
K1 | 0.0341 (5) | 0.0427 (6) | 0.0337 (5) | 0.0073 (4) | 0.0085 (4) | 0.0126 (4) |
Na1 | 0.0277 (8) | 0.0454 (10) | 0.0294 (8) | −0.0050 (7) | −0.0032 (7) | 0.0014 (7) |
S1 | 0.0282 (5) | 0.0272 (5) | 0.0279 (5) | 0.0013 (4) | −0.0018 (4) | −0.0016 (4) |
C1 | 0.028 (2) | 0.0202 (19) | 0.028 (2) | 0.0081 (16) | 0.0035 (17) | 0.0020 (16) |
C2 | 0.029 (2) | 0.027 (2) | 0.0199 (18) | 0.0058 (17) | 0.0085 (16) | 0.0012 (16) |
C3 | 0.0237 (19) | 0.031 (2) | 0.025 (2) | −0.0014 (17) | 0.0079 (16) | 0.0009 (17) |
C4 | 0.0203 (17) | 0.0171 (17) | 0.0181 (18) | 0.0039 (15) | 0.0013 (14) | 0.0016 (14) |
C5 | 0.0214 (17) | 0.0175 (18) | 0.0164 (17) | 0.0031 (14) | 0.0023 (14) | 0.0006 (14) |
C6 | 0.0227 (18) | 0.0184 (17) | 0.0177 (17) | 0.0008 (15) | 0.0036 (14) | 0.0000 (14) |
C7 | 0.0208 (18) | 0.029 (2) | 0.0194 (18) | −0.0079 (16) | −0.0003 (15) | −0.0035 (16) |
N1 | 0.041 (2) | 0.032 (2) | 0.038 (2) | 0.0024 (17) | −0.0083 (18) | −0.0031 (17) |
N2 | 0.0206 (15) | 0.0276 (17) | 0.0234 (16) | 0.0003 (14) | 0.0041 (13) | −0.0018 (14) |
N3 | 0.0242 (15) | 0.0193 (15) | 0.0150 (14) | 0.0037 (13) | 0.0032 (12) | −0.0009 (12) |
O1 | 0.0324 (15) | 0.056 (2) | 0.0220 (14) | 0.0086 (15) | −0.0050 (12) | 0.0014 (14) |
O2 | 0.0276 (14) | 0.0387 (16) | 0.0244 (14) | 0.0037 (13) | 0.0054 (11) | −0.0079 (12) |
O3 | 0.0210 (13) | 0.0346 (16) | 0.0222 (13) | −0.0010 (12) | 0.0017 (11) | −0.0058 (12) |
O4 | 0.0274 (14) | 0.0298 (15) | 0.0197 (13) | −0.0050 (12) | 0.0052 (11) | 0.0003 (11) |
O1W | 0.0338 (16) | 0.054 (2) | 0.0436 (18) | 0.0018 (15) | 0.0078 (14) | −0.0070 (16) |
Cu1—N3 | 1.970 (3) | C2—H1A | 0.930 |
Cu1—N3i | 1.970 (3) | C3—N2 | 1.332 (5) |
Cu1—O3 | 1.971 (3) | C3—H2A | 0.930 |
Cu1—O3i | 1.971 (3) | C4—N2 | 1.350 (5) |
K1—O4ii | 2.776 (3) | C4—C5 | 1.396 (5) |
K1—O2ii | 2.820 (3) | C4—C7 | 1.520 (5) |
K1—O4 | 2.882 (3) | C5—N3 | 1.346 (4) |
K1—O1iii | 2.906 (3) | C5—C6 | 1.518 (5) |
K1—O1Wiv | 2.912 (4) | C6—O4 | 1.237 (4) |
K1—O2v | 2.928 (3) | C6—O3 | 1.276 (4) |
K1—N1vi | 3.018 (4) | C7—O2 | 1.248 (5) |
K1—O1 | 3.239 (3) | C7—O1 | 1.256 (5) |
Na1—N1 | 2.370 (4) | N1—K1vii | 3.018 (4) |
Na1—O2ii | 2.413 (3) | O1—Na1vi | 2.596 (4) |
Na1—O1W | 2.445 (4) | O1—Na1iv | 2.710 (3) |
Na1—O4 | 2.465 (3) | O1—K1viii | 2.906 (3) |
Na1—O1vii | 2.596 (4) | O2—Na1iv | 2.413 (3) |
Na1—O1ii | 2.710 (3) | O2—K1iv | 2.820 (3) |
S1—C1 | 1.652 (4) | O2—K1ix | 2.928 (3) |
C1—N1 | 1.161 (5) | O4—K1iv | 2.776 (3) |
C2—N3 | 1.330 (5) | O1W—K1ii | 2.912 (4) |
C2—C3 | 1.380 (6) | ||
N3—Cu1—N3i | 180.00 (15) | N3—C2—C3 | 119.8 (3) |
N3—Cu1—O3 | 82.42 (11) | N3—C2—H1A | 120.1 |
N3i—Cu1—O3 | 97.58 (11) | C3—C2—H1A | 120.1 |
N3—Cu1—O3i | 97.58 (11) | N2—C3—C2 | 122.5 (3) |
N3i—Cu1—O3i | 82.42 (11) | N2—C3—H2A | 118.8 |
O3—Cu1—O3i | 180.00 (7) | C2—C3—H2A | 118.8 |
O4ii—K1—O2ii | 66.29 (8) | N2—C4—C5 | 120.5 (3) |
O4ii—K1—O4 | 132.08 (5) | N2—C4—C7 | 113.4 (3) |
O2ii—K1—O4 | 67.09 (8) | C5—C4—C7 | 126.0 (3) |
O4ii—K1—O1iii | 84.30 (8) | N3—C5—C4 | 120.1 (3) |
O2ii—K1—O1iii | 144.84 (8) | N3—C5—C6 | 113.5 (3) |
O4—K1—O1iii | 143.29 (9) | C4—C5—C6 | 126.3 (3) |
O4ii—K1—O1Wiv | 81.20 (9) | O4—C6—O3 | 125.0 (3) |
O2ii—K1—O1Wiv | 71.14 (9) | O4—C6—C5 | 120.4 (3) |
O4—K1—O1Wiv | 93.95 (9) | O3—C6—C5 | 114.6 (3) |
O1iii—K1—O1Wiv | 86.26 (9) | O2—C7—O1 | 126.8 (3) |
O4ii—K1—O2v | 67.01 (8) | O2—C7—C4 | 118.4 (3) |
O2ii—K1—O2v | 112.66 (9) | O1—C7—C4 | 114.6 (3) |
O4—K1—O2v | 124.03 (8) | C1—N1—Na1 | 170.2 (3) |
O1iii—K1—O2v | 69.10 (9) | C1—N1—K1vii | 103.6 (3) |
O1Wiv—K1—O2v | 140.92 (9) | Na1—N1—K1vii | 85.12 (12) |
O4ii—K1—N1vi | 140.93 (10) | C3—N2—C4 | 117.6 (3) |
O2ii—K1—N1vi | 138.63 (9) | C2—N3—C5 | 119.4 (3) |
O4—K1—N1vi | 75.49 (9) | C2—N3—Cu1 | 127.8 (3) |
O1iii—K1—N1vi | 76.50 (9) | C5—N3—Cu1 | 112.8 (2) |
O1Wiv—K1—N1vi | 130.05 (10) | C7—O1—Na1vi | 129.1 (2) |
O2v—K1—N1vi | 74.38 (9) | C7—O1—Na1iv | 83.7 (2) |
O4ii—K1—O1 | 139.44 (8) | Na1vi—O1—Na1iv | 147.18 (12) |
O2ii—K1—O1 | 114.56 (9) | C7—O1—K1viii | 123.2 (3) |
O4—K1—O1 | 72.16 (7) | Na1vi—O1—K1viii | 80.12 (9) |
O1iii—K1—O1 | 75.41 (5) | Na1iv—O1—K1viii | 81.66 (9) |
O1Wiv—K1—O1 | 63.00 (8) | C7—O1—K1 | 97.5 (2) |
O2v—K1—O1 | 132.52 (8) | Na1vi—O1—K1 | 77.22 (9) |
N1vi—K1—O1 | 67.34 (9) | Na1iv—O1—K1 | 99.83 (9) |
N1—Na1—O2ii | 142.25 (13) | K1viii—O1—K1 | 138.99 (11) |
N1—Na1—O1W | 85.88 (13) | C7—O2—Na1iv | 97.5 (2) |
O2ii—Na1—O1W | 94.13 (12) | C7—O2—K1iv | 123.5 (2) |
N1—Na1—O4 | 137.22 (13) | Na1iv—O2—K1iv | 91.41 (9) |
O2ii—Na1—O4 | 80.48 (10) | C7—O2—K1ix | 143.4 (2) |
O1W—Na1—O4 | 94.69 (11) | Na1iv—O2—K1ix | 82.67 (9) |
N1—Na1—O1vii | 88.66 (12) | K1iv—O2—K1ix | 92.98 (8) |
O2ii—Na1—O1vii | 82.60 (10) | C6—O3—Cu1 | 114.0 (2) |
O1W—Na1—O1vii | 166.35 (13) | C6—O4—Na1 | 111.9 (2) |
O4—Na1—O1vii | 97.81 (11) | C6—O4—K1iv | 136.4 (2) |
N1—Na1—O1ii | 92.23 (12) | Na1—O4—K1iv | 85.02 (9) |
O2ii—Na1—O1ii | 51.43 (9) | C6—O4—K1 | 124.0 (2) |
O1W—Na1—O1ii | 77.29 (11) | Na1—O4—K1 | 88.92 (9) |
O4—Na1—O1ii | 129.70 (10) | K1iv—O4—K1 | 94.92 (8) |
O1vii—Na1—O1ii | 90.46 (6) | Na1—O1W—K1ii | 116.59 (12) |
N1—C1—S1 | 179.0 (4) |
Symmetry codes: (i) −x+1, −y+1, −z; (ii) −x+1, y−1/2, −z+1/2; (iii) −x+2, y−1/2, −z+1/2; (iv) −x+1, y+1/2, −z+1/2; (v) x, y−1, z; (vi) x+1, y, z; (vii) x−1, y, z; (viii) −x+2, y+1/2, −z+1/2; (ix) x, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | Na2K2[Cu(C6H2N2O4)2](SCN)2·2H2O |
Mr | 672.10 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 293 |
a, b, c (Å) | 6.8349 (7), 6.9692 (7), 23.184 (2) |
β (°) | 90.797 (2) |
V (Å3) | 1104.23 (19) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 1.66 |
Crystal size (mm) | 0.68 × 0.22 × 0.18 |
Data collection | |
Diffractometer | Siemens SMART CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.514, 0.741 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3306, 1929, 1663 |
Rint | 0.025 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.040, 0.106, 1.00 |
No. of reflections | 1929 |
No. of parameters | 169 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.50, −0.64 |
Computer programs: SMART (Siemens, 1996), SMART and SAINT (Siemens, 1994), SAINT and SHELXTL (Siemens, 1994), SHELXTL.
Cu1—N3 | 1.970 (3) | Na1—N1 | 2.370 (4) |
Cu1—O3 | 1.971 (3) | Na1—O2i | 2.413 (3) |
K1—O4i | 2.776 (3) | Na1—O1W | 2.445 (4) |
K1—O2i | 2.820 (3) | Na1—O4 | 2.465 (3) |
K1—O4 | 2.882 (3) | Na1—O1vi | 2.596 (4) |
K1—O1ii | 2.906 (3) | Na1—O1i | 2.710 (3) |
K1—O1Wiii | 2.912 (4) | C6—O4 | 1.237 (4) |
K1—O2iv | 2.928 (3) | C6—O3 | 1.276 (4) |
K1—N1v | 3.018 (4) | C7—O2 | 1.248 (5) |
K1—O1 | 3.239 (3) | C7—O1 | 1.256 (5) |
N3—Cu1—O3 | 82.42 (11) | O2—C7—O1 | 126.8 (3) |
O4—C6—O3 | 125.0 (3) | O2—C7—C4 | 118.4 (3) |
O4—C6—C5 | 120.4 (3) | C6—O3—Cu1 | 114.0 (2) |
Symmetry codes: (i) −x+1, y−1/2, −z+1/2; (ii) −x+2, y−1/2, −z+1/2; (iii) −x+1, y+1/2, −z+1/2; (iv) x, y−1, z; (v) x+1, y, z; (vi) x−1, y, z. |
Takusagawa & Shimada (1973) first determined the structure of pyrazine-2,3-dicarboxlic acid by single-crystal X-ray analysis. Almost at the same time, the first metal-organic compound of pyrazine-2,3-dicarboxylic acid was reported (Richard et al., 1973). More recently, owing to the interest in supramolecular chemistry, pyrazine-2,3-dicarboxylic acid has been intensely investigated (Smith et al., 1995; Neels et al., 1997; Kondo et al., 1999). For further investigation of pyrazine-2,3-dicarboxylic acid, we synthesized the t itle compound, (I), with a new coordination mode for copper in such complexes. An interesting phenomenon was noted during the synthesis; a blue solid precipitated when pyrazine-2,3-dicarboxylate was added to Cu(NO3)2·3H2O in water, but no product was deposited in the present of SCN−. Here we report the synthesis and crystal structure of the title compound.
Compound (I) is composed of K+ and Na+ cations, [trans-Cu(C6H2N2O4)2]2− and SCN− anions, and water molecules. As shown in Fig. 1, the CuII atom has centrosymmetric square-planar coordination with trans-positioned O– and N-donor atoms of two pyrazine-2,3-dicarboxylate ligands. The bond distances Cu1—O3 and Cu1—N3 are 1.971 (3) and 1.970 (3) Å, respectively, almost equal to each other, unlike those found in other CuII complexes of pyrazine-2,3-dicarboxylate (Smith et al., 1995; Neels et al., 1997; Kondo et al., 1999). As in the structures of C14H8CuN2O8·2H2O (Yucang, Maochun, Rong & Qian, 2001) and (C28H24CuGd2N4O22)n.2nH2O (Yucang, Maochun, Wiping et al., 2001), the C—O bond distance of the carboxylate group involving the O atom coordinated to copper in the present compound [C6—O3 = 1.276 (4) Å] is a little onger than the other [C6—O4 = 1.237 (4) Å]. However, the two C—O bond distances of the uncoordinated carboxylate group are almost equal, as found in the structure of (C14H22CuN2Na2O16)n (Sileo et al., 1999).
As shown in Fig. 2, the three-dimensional framework is constructed through electrostatic interactions among [trans-Cu(C6H2N2O4)2]2−, SCN−, K+ and Na+ ions, together with water molecules. O—H···N hydrogen bonds are found between O1W and the uncoordinated N atom of pyrazine-2,3-dicarboxylate, with a distance of 2.985 (5) Å. Na is six-coordinated, by five O atoms and one N atom, while K is eight-coordinated, by seven O atoms and one N atom (Table 1).