
Supporting information
![]() | Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807022544/lh2377sup1.cif |
![]() | Structure factor file (CIF format) https://doi.org/10.1107/S1600536807022544/lh2377Isup2.hkl |
CCDC reference: 297286
Hot aqueous solutions containing 2 mmol s of pyridazine-3-carboxylic acid and 1 mmol of calcium(II) acetate tetrahydrate, respectively, were mixed and boiled for one hour with constant stirring. After cooling to room temperature, 5 ml of 3 N acetic acid were added. The solution when evaporated to dryness at room temperature, over several days, provided rectangular blocks as single crystals. They were washed with cold ethanol and dried in air.
The structure of compound (1) is composed of discrete, dinuclear centrosymmetric units consisting of two CaII ions bridged by two carboxylate oxygen atoms each donated by the ligand molecule coordinated to a different CaII ion. Figure 1 shows the molecular structure of a dimer with atom labelling scheme; Figure 2 illustrates the way the dimers are packed in the crystal. The CaII ion is coordinated by two pyridazine-3-carboxylate ligands via their N,O bonding groups. In both, only one carboxylate O atom participates in coordination. Pyridazine rings are planar with r.m.s. of 0.0074 Å and 0.0050Å for the two symmetry unique ligand molecules. The planes of the rings make an angle of 84.0° each to the other. The planes of the carboxylate groups make the angles of 11.6° and 0.2° with the two pyridazine rings to which they are bonded. Bond distances and bond angles within the ligand molecules agree well with those reported earlier for the parent acid (Gryz et al., 2003). The coordinated carboxylate oxygen atom of one ligand molecule acts as bidentate being coordinated to the symmetry related CaII ion, thus forming two bridges Ca – O11 – Cai and Ca – O11i – Cai [symmetry code as in Table 1]. Apart from the two N,O bonding groups and the bridging carboxylate O atom, each CaII ion is also coordinated by three O atoms of water molecules. The coordination number of each CaII ion is eight and the coordination geometry is represented by a severely distorted decahedron, similar to that observed in a Ca complex with pyrazine-2-carboxylate and water ligands (Ptasiewicz-Bąk & et al., 1998). One of the strongly distorted tetragonal bases (r.m.s 0.2715 Å) is composed of O11, N12, O21 and N22 atoms, the other base (r.m.s. 0.2990 Å) is formed by three water oxygen O (O1, O2, O3) and the bridging carboxylate O atom O11i. The bases are almost parallel making an angle of 6.1° but the tetragons are rotated by ca 45°, one in respect to the other. The observed Ca—O bond distances and angles are typical for calcium complexes with carboxylate ligands (Einspahr & Bugg, 1981). Coordinated water molecules act as donors in hydrogen bonds to the carboxylate oxygen atoms and hetero-ring nitrogen atoms in adjacent dimers (Fig. 2). Intradimeric hydrogen bonds are also observed. For details – see Table 2.
We have recently determined the structure of the free ligand (Gryz et al., 2003) and a related structure has also been reported (Ptasiewicz-Bąk et al., 1998). The bond lengths and angles in the title compound are typical (Einspahr & Bugg, 1981).
Data collection: KM-4 Software (Kuma Diffraction, 1996); cell refinement: KM-4 Software; data reduction: DATAPROC (Kuma Diffraction, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1992) and PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.
[Ca2(C5H3N2O2)2(H2O)6] | F(000) = 704 |
Mr = 680.63 | Dx = 1.582 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 25 reflections |
a = 9.1730 (18) Å | θ = 6–15° |
b = 10.539 (2) Å | µ = 0.48 mm−1 |
c = 14.984 (3) Å | T = 293 K |
β = 99.43 (3)° | Rectangular block, colourless |
V = 1429.0 (5) Å3 | 0.54 × 0.22 × 0.18 mm |
Z = 2 |
Kuma KM4 four-circle diffractometer | 3154 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.017 |
Graphite monochromator | θmax = 30.1°, θmin = 2.4° |
profile data from θ/2θ scans | h = 0→12 |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2000) | k = −14→0 |
Tmin = 0.877, Tmax = 0.901 | l = −21→20 |
4432 measured reflections | 3 standard reflections every 200 reflections |
4182 independent reflections | intensity decay: 2.5% |
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)] = 0.033 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.102 | Only H-atom coordinates refined |
S = 0.98 | w = 1/[σ2(Fo2) + (0.0631P)2 + 0.4166P] where P = (Fo2 + 2Fc2)/3 |
4182 reflections | (Δ/σ)max = 0.001 |
247 parameters | Δρmax = 0.35 e Å−3 |
0 restraints | Δρmin = −0.48 e Å−3 |
[Ca2(C5H3N2O2)2(H2O)6] | V = 1429.0 (5) Å3 |
Mr = 680.63 | Z = 2 |
Monoclinic, P21/n | Mo Kα radiation |
a = 9.1730 (18) Å | µ = 0.48 mm−1 |
b = 10.539 (2) Å | T = 293 K |
c = 14.984 (3) Å | 0.54 × 0.22 × 0.18 mm |
β = 99.43 (3)° |
Kuma KM4 four-circle diffractometer | 3154 reflections with I > 2σ(I) |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2000) | Rint = 0.017 |
Tmin = 0.877, Tmax = 0.901 | 3 standard reflections every 200 reflections |
4432 measured reflections | intensity decay: 2.5% |
4182 independent reflections |
R[F2 > 2σ(F2)] = 0.033 | 0 restraints |
wR(F2) = 0.102 | Only H-atom coordinates refined |
S = 0.98 | Δρmax = 0.35 e Å−3 |
4182 reflections | Δρmin = −0.48 e Å−3 |
247 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 | ||
Ca1 | 0.65075 (3) | 0.88232 (3) | 0.575164 (18) | 0.02345 (8) | |
O11 | 0.39476 (11) | 0.95185 (10) | 0.55635 (7) | 0.0282 (2) | |
N12 | 0.49408 (13) | 0.77300 (12) | 0.68154 (8) | 0.0277 (2) | |
O3 | 0.67401 (17) | 1.08313 (13) | 0.64699 (10) | 0.0474 (3) | |
O2 | 0.87173 (14) | 0.87577 (15) | 0.51303 (10) | 0.0434 (3) | |
O1 | 0.83709 (16) | 0.83982 (14) | 0.70706 (9) | 0.0473 (3) | |
O21 | 0.53629 (13) | 0.76031 (11) | 0.44708 (8) | 0.0391 (3) | |
C17 | 0.30113 (15) | 0.89606 (14) | 0.59370 (10) | 0.0279 (3) | |
O12 | 0.16530 (13) | 0.90909 (17) | 0.57563 (12) | 0.0590 (4) | |
N22 | 0.73182 (16) | 0.64577 (12) | 0.57056 (9) | 0.0327 (3) | |
N11 | 0.54731 (15) | 0.68921 (14) | 0.74637 (10) | 0.0362 (3) | |
C13 | 0.35352 (16) | 0.80508 (14) | 0.66984 (9) | 0.0270 (3) | |
C23 | 0.68131 (18) | 0.58150 (14) | 0.49646 (10) | 0.0317 (3) | |
O22 | 0.5225 (2) | 0.59002 (14) | 0.35821 (10) | 0.0611 (4) | |
N21 | 0.8315 (2) | 0.59353 (15) | 0.63436 (11) | 0.0501 (4) | |
C27 | 0.56975 (18) | 0.64986 (15) | 0.42743 (11) | 0.0341 (3) | |
C14 | 0.2554 (2) | 0.7596 (2) | 0.72419 (13) | 0.0436 (4) | |
C16 | 0.4569 (2) | 0.6429 (2) | 0.79794 (14) | 0.0474 (4) | |
C24 | 0.7276 (3) | 0.45936 (19) | 0.48169 (15) | 0.0575 (6) | |
C15 | 0.3101 (2) | 0.6764 (2) | 0.79061 (15) | 0.0544 (5) | |
C26 | 0.8765 (3) | 0.4766 (2) | 0.62310 (16) | 0.0648 (7) | |
C25 | 0.8276 (4) | 0.4049 (2) | 0.54776 (18) | 0.0713 (8) | |
H31 | 0.610 (3) | 1.141 (3) | 0.6249 (19) | 0.062 (7)* | |
H11 | 0.885 (3) | 0.862 (2) | 0.7526 (18) | 0.049 (6)* | |
H14 | 0.152 (3) | 0.789 (2) | 0.7140 (16) | 0.056 (7)* | |
H15 | 0.253 (3) | 0.649 (3) | 0.830 (2) | 0.073 (8)* | |
H16 | 0.504 (3) | 0.586 (2) | 0.8425 (17) | 0.057 (7)* | |
H23 | 0.687 (3) | 0.418 (3) | 0.427 (2) | 0.078 (9)* | |
H25 | 0.955 (4) | 0.446 (3) | 0.674 (2) | 0.090 (10)* | |
H24 | 0.870 (3) | 0.324 (3) | 0.5399 (19) | 0.070 (8)* | |
H12 | 0.853 (3) | 0.755 (3) | 0.706 (2) | 0.090 (10)* | |
H32 | 0.734 (3) | 1.108 (2) | 0.6894 (18) | 0.056 (7)* | |
H21 | 0.949 (3) | 0.873 (3) | 0.546 (2) | 0.071 (9)* | |
H22 | 0.869 (3) | 0.949 (3) | 0.4853 (17) | 0.056 (7)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ca1 | 0.02048 (13) | 0.02388 (13) | 0.02488 (13) | −0.00055 (9) | 0.00039 (9) | −0.00032 (9) |
O11 | 0.0232 (4) | 0.0304 (5) | 0.0308 (5) | 0.0006 (4) | 0.0035 (4) | 0.0058 (4) |
N12 | 0.0272 (6) | 0.0278 (6) | 0.0273 (6) | 0.0009 (4) | 0.0023 (4) | 0.0029 (4) |
O3 | 0.0530 (8) | 0.0348 (6) | 0.0445 (7) | 0.0109 (6) | −0.0219 (6) | −0.0133 (5) |
O2 | 0.0257 (5) | 0.0553 (8) | 0.0487 (7) | 0.0012 (5) | 0.0045 (5) | 0.0161 (6) |
O1 | 0.0538 (8) | 0.0407 (7) | 0.0384 (6) | −0.0004 (6) | −0.0195 (6) | −0.0027 (5) |
O21 | 0.0415 (6) | 0.0282 (5) | 0.0409 (6) | 0.0060 (5) | −0.0129 (5) | −0.0040 (5) |
C17 | 0.0230 (6) | 0.0284 (6) | 0.0315 (7) | 0.0002 (5) | 0.0018 (5) | 0.0024 (5) |
O12 | 0.0218 (5) | 0.0739 (10) | 0.0796 (11) | 0.0013 (6) | 0.0035 (6) | 0.0423 (8) |
N22 | 0.0407 (7) | 0.0270 (6) | 0.0273 (6) | 0.0034 (5) | −0.0042 (5) | 0.0013 (5) |
N11 | 0.0355 (7) | 0.0360 (7) | 0.0360 (7) | 0.0059 (5) | 0.0023 (5) | 0.0098 (5) |
C13 | 0.0284 (6) | 0.0258 (6) | 0.0266 (6) | 0.0005 (5) | 0.0044 (5) | 0.0010 (5) |
C23 | 0.0396 (8) | 0.0247 (6) | 0.0284 (7) | 0.0011 (6) | −0.0013 (6) | −0.0006 (5) |
O22 | 0.0825 (11) | 0.0446 (7) | 0.0432 (7) | 0.0131 (7) | −0.0288 (7) | −0.0143 (6) |
N21 | 0.0691 (11) | 0.0380 (8) | 0.0348 (7) | 0.0142 (7) | −0.0166 (7) | 0.0015 (6) |
C27 | 0.0384 (8) | 0.0281 (7) | 0.0315 (7) | 0.0013 (6) | −0.0068 (6) | −0.0013 (6) |
C14 | 0.0347 (8) | 0.0509 (10) | 0.0488 (10) | 0.0073 (7) | 0.0172 (7) | 0.0159 (8) |
C16 | 0.0504 (10) | 0.0490 (10) | 0.0437 (9) | 0.0084 (8) | 0.0104 (8) | 0.0213 (8) |
C24 | 0.0833 (15) | 0.0335 (9) | 0.0472 (10) | 0.0159 (10) | −0.0143 (10) | −0.0117 (8) |
C15 | 0.0524 (11) | 0.0641 (13) | 0.0522 (11) | 0.0086 (10) | 0.0250 (9) | 0.0265 (10) |
C26 | 0.0882 (17) | 0.0422 (10) | 0.0527 (12) | 0.0239 (11) | −0.0219 (12) | 0.0050 (9) |
C25 | 0.103 (2) | 0.0350 (10) | 0.0650 (14) | 0.0299 (12) | −0.0179 (13) | −0.0060 (9) |
Ca1—O2 | 2.3662 (14) | C17—O12 | 1.2385 (19) |
Ca1—O3 | 2.3680 (13) | C17—C13 | 1.508 (2) |
Ca1—O21 | 2.4040 (13) | N22—C23 | 1.3183 (19) |
Ca1—O11 | 2.4318 (11) | N22—N21 | 1.3294 (19) |
Ca1—O1 | 2.4334 (15) | N11—C16 | 1.317 (2) |
Ca1—N12 | 2.5853 (14) | C13—C14 | 1.394 (2) |
Ca1—N22 | 2.6057 (14) | C23—C24 | 1.385 (2) |
Ca1—O11i | 2.6158 (11) | C23—C27 | 1.513 (2) |
Ca1—Ca1i | 4.1029 (11) | O22—C27 | 1.230 (2) |
Ca1—H22 | 2.68 (3) | N21—C26 | 1.319 (3) |
O11—C17 | 1.2466 (17) | C14—C15 | 1.359 (3) |
O11—Ca1i | 2.6158 (11) | C14—H14 | 0.99 (3) |
N12—C13 | 1.3166 (19) | C16—C15 | 1.379 (3) |
N12—N11 | 1.3440 (18) | C16—H16 | 0.95 (3) |
O3—H31 | 0.87 (3) | C24—C25 | 1.361 (3) |
O3—H32 | 0.81 (3) | C24—H23 | 0.95 (3) |
O2—H21 | 0.79 (3) | C15—H15 | 0.90 (3) |
O2—H22 | 0.87 (3) | C26—C25 | 1.371 (3) |
O1—H11 | 0.78 (3) | C26—H25 | 1.01 (3) |
O1—H12 | 0.91 (4) | C25—H24 | 0.96 (3) |
O21—C27 | 1.251 (2) | ||
O2—Ca1—O3 | 100.70 (6) | C13—N12—N11 | 119.79 (13) |
O2—Ca1—O21 | 87.74 (5) | C13—N12—Ca1 | 115.76 (9) |
O3—Ca1—O21 | 146.71 (4) | N11—N12—Ca1 | 124.45 (10) |
O2—Ca1—O11 | 146.76 (4) | Ca1—O3—H31 | 116.4 (18) |
O3—Ca1—O11 | 78.27 (5) | Ca1—O3—H32 | 129.8 (18) |
O21—Ca1—O11 | 77.38 (5) | H31—O3—H32 | 114 (2) |
O2—Ca1—O1 | 77.35 (6) | Ca1—O2—H21 | 119 (2) |
O3—Ca1—O1 | 78.25 (5) | Ca1—O2—H22 | 101.5 (17) |
O21—Ca1—O1 | 134.97 (5) | H21—O2—H22 | 107 (3) |
O11—Ca1—O1 | 133.32 (5) | Ca1—O1—H11 | 150.3 (18) |
O2—Ca1—N12 | 145.91 (5) | Ca1—O1—H12 | 105 (2) |
O3—Ca1—N12 | 97.81 (5) | H11—O1—H12 | 104 (3) |
O21—Ca1—N12 | 92.27 (5) | C27—O21—Ca1 | 126.41 (10) |
O11—Ca1—N12 | 65.29 (4) | O12—C17—O11 | 126.30 (14) |
O1—Ca1—N12 | 78.74 (5) | O12—C17—C13 | 114.87 (13) |
O2—Ca1—N22 | 72.25 (5) | O11—C17—C13 | 118.82 (12) |
O3—Ca1—N22 | 149.57 (5) | C23—N22—N21 | 119.89 (14) |
O21—Ca1—N22 | 63.66 (4) | C23—N22—Ca1 | 116.83 (10) |
O11—Ca1—N22 | 124.03 (4) | N21—N22—Ca1 | 122.89 (10) |
O1—Ca1—N22 | 71.33 (5) | C16—N11—N12 | 118.60 (14) |
N12—Ca1—N22 | 77.28 (5) | N12—C13—C14 | 123.08 (14) |
O2—Ca1—O11i | 76.37 (5) | N12—C13—C17 | 116.61 (12) |
O3—Ca1—O11i | 74.73 (5) | C14—C13—C17 | 120.31 (13) |
O21—Ca1—O11i | 76.17 (4) | N22—C23—C24 | 122.52 (15) |
O11—Ca1—O11i | 71.30 (4) | N22—C23—C27 | 115.86 (13) |
O1—Ca1—O11i | 137.64 (5) | C24—C23—C27 | 121.62 (15) |
N12—Ca1—O11i | 136.55 (4) | C26—N21—N22 | 119.19 (16) |
N22—Ca1—O11i | 129.07 (4) | O22—C27—O21 | 127.52 (15) |
O2—Ca1—Ca1i | 110.21 (4) | O22—C27—C23 | 115.95 (15) |
O3—Ca1—Ca1i | 73.24 (4) | O21—C27—C23 | 116.53 (13) |
O21—Ca1—Ca1i | 73.63 (3) | C15—C14—C13 | 116.98 (16) |
O11—Ca1—Ca1i | 37.15 (3) | C15—C14—H14 | 123.2 (14) |
O1—Ca1—Ca1i | 151.38 (4) | C13—C14—H14 | 119.8 (14) |
N12—Ca1—Ca1i | 102.42 (3) | N11—C16—C15 | 123.98 (17) |
N22—Ca1—Ca1i | 137.18 (3) | N11—C16—H16 | 112.9 (15) |
O11i—Ca1—Ca1i | 34.15 (2) | C15—C16—H16 | 123.1 (15) |
O2—Ca1—H22 | 18.6 (6) | C25—C24—C23 | 117.60 (18) |
O3—Ca1—H22 | 88.6 (6) | C25—C24—H23 | 123.5 (19) |
O21—Ca1—H22 | 90.2 (6) | C23—C24—H23 | 118.9 (19) |
O11—Ca1—H22 | 130.5 (6) | C14—C15—C16 | 117.52 (17) |
O1—Ca1—H22 | 88.5 (6) | C14—C15—H15 | 120.4 (19) |
N12—Ca1—H22 | 164.1 (6) | C16—C15—H15 | 122.0 (18) |
N22—Ca1—H22 | 89.8 (6) | N21—C26—C25 | 123.58 (19) |
O11i—Ca1—H22 | 59.1 (6) | N21—C26—H25 | 113.6 (19) |
Ca1i—Ca1—H22 | 93.3 (6) | C25—C26—H25 | 122.7 (19) |
C17—O11—Ca1 | 121.94 (9) | C24—C25—C26 | 117.19 (19) |
C17—O11—Ca1i | 128.07 (9) | C24—C25—H24 | 121.8 (17) |
Ca1—O11—Ca1i | 108.70 (4) | C26—C25—H24 | 120.7 (17) |
Symmetry code: (i) −x+1, −y+2, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H31···O21i | 0.87 (3) | 1.89 (3) | 2.7458 (18) | 166 (3) |
O1—H11···O22ii | 0.78 (3) | 1.92 (3) | 2.703 (2) | 173 (2) |
O1—H12···N21 | 0.91 (4) | 2.00 (4) | 2.812 (2) | 148 (3) |
O1—H12···N22 | 0.91 (4) | 2.43 (3) | 2.941 (2) | 116 (2) |
O3—H32···N11iii | 0.81 (3) | 2.25 (3) | 3.000 (2) | 154 (2) |
O2—H21···O12iv | 0.79 (3) | 2.00 (3) | 2.725 (2) | 152 (3) |
O2—H22···O12i | 0.87 (3) | 1.76 (3) | 2.622 (2) | 171 (3) |
O2—H22···O11i | 0.87 (3) | 2.61 (3) | 3.0861 (18) | 115 (2) |
Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) x+1/2, −y+3/2, z+1/2; (iii) −x+3/2, y+1/2, −z+3/2; (iv) x+1, y, z. |
Experimental details
Crystal data | |
Chemical formula | [Ca2(C5H3N2O2)2(H2O)6] |
Mr | 680.63 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 9.1730 (18), 10.539 (2), 14.984 (3) |
β (°) | 99.43 (3) |
V (Å3) | 1429.0 (5) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.48 |
Crystal size (mm) | 0.54 × 0.22 × 0.18 |
Data collection | |
Diffractometer | Kuma KM4 four-circle |
Absorption correction | Analytical (CrysAlis RED; Oxford Diffraction, 2000) |
Tmin, Tmax | 0.877, 0.901 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4432, 4182, 3154 |
Rint | 0.017 |
(sin θ/λ)max (Å−1) | 0.705 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.033, 0.102, 0.98 |
No. of reflections | 4182 |
No. of parameters | 247 |
H-atom treatment | Only H-atom coordinates refined |
Δρmax, Δρmin (e Å−3) | 0.35, −0.48 |
Computer programs: KM-4 Software (Kuma Diffraction, 1996), KM-4 Software, DATAPROC (Kuma Diffraction, 2001), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), XP (Siemens, 1992) and PLATON (Spek, 2003), SHELXL97.
Ca1—O2 | 2.3662 (14) | Ca1—O1 | 2.4334 (15) |
Ca1—O3 | 2.3680 (13) | Ca1—N12 | 2.5853 (14) |
Ca1—O21 | 2.4040 (13) | Ca1—N22 | 2.6057 (14) |
Ca1—O11 | 2.4318 (11) | Ca1—O11i | 2.6158 (11) |
O21—Ca1—O11 | 77.38 (5) | O21—Ca1—N22 | 63.66 (4) |
O2—Ca1—O1 | 77.35 (6) | N12—Ca1—N22 | 77.28 (5) |
O3—Ca1—O1 | 78.25 (5) | O2—Ca1—O11i | 76.37 (5) |
O11—Ca1—N12 | 65.29 (4) | O3—Ca1—O11i | 74.73 (5) |
Symmetry code: (i) −x+1, −y+2, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H31···O21i | 0.87 (3) | 1.89 (3) | 2.7458 (18) | 166 (3) |
O1—H11···O22ii | 0.78 (3) | 1.92 (3) | 2.703 (2) | 173 (2) |
O1—H12···N21 | 0.91 (4) | 2.00 (4) | 2.812 (2) | 148 (3) |
O1—H12···N22 | 0.91 (4) | 2.43 (3) | 2.941 (2) | 116 (2) |
O3—H32···N11iii | 0.81 (3) | 2.25 (3) | 3.000 (2) | 154 (2) |
O2—H21···O12iv | 0.79 (3) | 2.00 (3) | 2.725 (2) | 152 (3) |
O2—H22···O12i | 0.87 (3) | 1.76 (3) | 2.622 (2) | 171 (3) |
O2—H22···O11i | 0.87 (3) | 2.61 (3) | 3.0861 (18) | 115 (2) |
Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) x+1/2, −y+3/2, z+1/2; (iii) −x+3/2, y+1/2, −z+3/2; (iv) x+1, y, z. |
The structure of compound (1) is composed of discrete, dinuclear centrosymmetric units consisting of two CaII ions bridged by two carboxylate oxygen atoms each donated by the ligand molecule coordinated to a different CaII ion. Figure 1 shows the molecular structure of a dimer with atom labelling scheme; Figure 2 illustrates the way the dimers are packed in the crystal. The CaII ion is coordinated by two pyridazine-3-carboxylate ligands via their N,O bonding groups. In both, only one carboxylate O atom participates in coordination. Pyridazine rings are planar with r.m.s. of 0.0074 Å and 0.0050Å for the two symmetry unique ligand molecules. The planes of the rings make an angle of 84.0° each to the other. The planes of the carboxylate groups make the angles of 11.6° and 0.2° with the two pyridazine rings to which they are bonded. Bond distances and bond angles within the ligand molecules agree well with those reported earlier for the parent acid (Gryz et al., 2003). The coordinated carboxylate oxygen atom of one ligand molecule acts as bidentate being coordinated to the symmetry related CaII ion, thus forming two bridges Ca – O11 – Cai and Ca – O11i – Cai [symmetry code as in Table 1]. Apart from the two N,O bonding groups and the bridging carboxylate O atom, each CaII ion is also coordinated by three O atoms of water molecules. The coordination number of each CaII ion is eight and the coordination geometry is represented by a severely distorted decahedron, similar to that observed in a Ca complex with pyrazine-2-carboxylate and water ligands (Ptasiewicz-Bąk & et al., 1998). One of the strongly distorted tetragonal bases (r.m.s 0.2715 Å) is composed of O11, N12, O21 and N22 atoms, the other base (r.m.s. 0.2990 Å) is formed by three water oxygen O (O1, O2, O3) and the bridging carboxylate O atom O11i. The bases are almost parallel making an angle of 6.1° but the tetragons are rotated by ca 45°, one in respect to the other. The observed Ca—O bond distances and angles are typical for calcium complexes with carboxylate ligands (Einspahr & Bugg, 1981). Coordinated water molecules act as donors in hydrogen bonds to the carboxylate oxygen atoms and hetero-ring nitrogen atoms in adjacent dimers (Fig. 2). Intradimeric hydrogen bonds are also observed. For details – see Table 2.