Bis(μ-pyridazine-3-carboxyl­ato)-κ³N,O:O;κ³O:N,O-bis­[triaqua­calcium(II)]

The structure of the title compound, [Ca₂(C₅H₃N₂O₂)₂(H₂O)₆], is composed of centrosymmetric dimeric mol­ecules, in which the Ca^II ions are bridged by two carboxyl­ate O atoms of bidentate ligands. Each Ca^II ion is coordinated by two carboxyl­ate O atoms, a hetero-ring N atom and three water O atoms. The coordination number of each Ca^II ion is eight, forming a distorted deca­hedron. Coordinated water mol­ecules act as donors linking adjacent dimers into a three-dimensional hydrogen-bonded network. Intra-dimer hydrogen bonds are also present.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.033
• wR factor = 0.102
• Data-to-parameter ratio = 16.9

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT164_ALERT_4_C Nr. of Refined C-H H-Atoms in Heavy-At Struct...          6
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       2.64 Ratio
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.05
PLAT480_ALERT_4_C Long H...A H-Bond Reported H22    ..  O11     ..       2.61 Ang.

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The structure of compound (1) is composed of discrete, dinuclear centrosymmetric units consisting of two Ca^II ions bridged by two carboxylate oxygen atoms each donated by the ligand molecule coordinated to a different Ca^II 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 Ca^II 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 Ca^II 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 Ca^II ion is also coordinated by three O atoms of water molecules. The coordination number of each Ca^II 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.

Related literature

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).

S2. Experimental

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.

S3. Refinement

H atoms were refined independently with isotropic displacement parameters.

Computing details

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.

Figures

	Fig. 1. The molecular structure of (1) with atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. Unlabeled atoms are related by the symmetry operator (-x + 1, -y + 2, -z + 1).
	Fig. 2. The packing of (1) with hydrogen bonds shown as dashed lines.

Bis(µ-pyridazine-3-carboxylato)-κ³N,O:O;κ³O:N,O-bis[triaquacalcium(II)]

Crystal data

[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) Å^3	0.54 × 0.22 × 0.18 mm
Z = 2

Data collection

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

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.102	Only H-atom coordinates refined
S = 0.98	w = 1/[σ^2(Fo^2) + (0.0631P)^2 + 0.4166P] where P = (Fo^2 + 2Fc^2)/3
4182 reflections	(Δ/σ)max = 0.001
247 parameters	Δρmax = 0.35 e Å^−3
0 restraints	Δρmin = −0.48 e Å^−3

Special details

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 (Ų)

	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)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
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)

Geometric parameters (Å, º)

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—O11^i	2.6158 (11)	C23—C27	1.513 (2)
Ca1—Ca1^i	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—Ca1^i	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—O11^i	76.37 (5)	N12—C13—C17	116.61 (12)
O3—Ca1—O11^i	74.73 (5)	C14—C13—C17	120.31 (13)
O21—Ca1—O11^i	76.17 (4)	N22—C23—C24	122.52 (15)
O11—Ca1—O11^i	71.30 (4)	N22—C23—C27	115.86 (13)
O1—Ca1—O11^i	137.64 (5)	C24—C23—C27	121.62 (15)
N12—Ca1—O11^i	136.55 (4)	C26—N21—N22	119.19 (16)
N22—Ca1—O11^i	129.07 (4)	O22—C27—O21	127.52 (15)
O2—Ca1—Ca1^i	110.21 (4)	O22—C27—C23	115.95 (15)
O3—Ca1—Ca1^i	73.24 (4)	O21—C27—C23	116.53 (13)
O21—Ca1—Ca1^i	73.63 (3)	C15—C14—C13	116.98 (16)
O11—Ca1—Ca1^i	37.15 (3)	C15—C14—H14	123.2 (14)
O1—Ca1—Ca1^i	151.38 (4)	C13—C14—H14	119.8 (14)
N12—Ca1—Ca1^i	102.42 (3)	N11—C16—C15	123.98 (17)
N22—Ca1—Ca1^i	137.18 (3)	N11—C16—H16	112.9 (15)
O11^i—Ca1—Ca1^i	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)
O11^i—Ca1—H22	59.1 (6)	N21—C26—H25	113.6 (19)
Ca1^i—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—Ca1^i	128.07 (9)	C24—C25—H24	121.8 (17)
Ca1—O11—Ca1^i	108.70 (4)	C26—C25—H24	120.7 (17)

Symmetry code: (i) −x+1, −y+2, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H31···O21^i	0.87 (3)	1.89 (3)	2.7458 (18)	166 (3)
O1—H11···O22^ii	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···N11^iii	0.81 (3)	2.25 (3)	3.000 (2)	154 (2)
O2—H21···O12^iv	0.79 (3)	2.00 (3)	2.725 (2)	152 (3)
O2—H22···O12^i	0.87 (3)	1.76 (3)	2.622 (2)	171 (3)
O2—H22···O11^i	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.