metal-organic compounds
Di-μ-aqua-bis(μ-pyridazine-4-carboxylato-κ2N:N′)bis[triaqua(pyridazine-4-carboxylato-κ2O,O′)lead(II)] dihydrate
aInstitute of Nuclear Chemistry and Technology, ul.Dorodna 16, 03-195 Warszawa, Poland
*Correspondence e-mail: j.leciejewicz@ichtj.waw.pl
The structure of the title compound, [Pb2(C5H3N2O2)4(H2O)6]·2H2O, is composed of dimeric molecules in which two symmetry-related Pb2+ ions are bridged by a pair of two pyridazine-4-carboxylate ligand molecules via both heterocyclic N atoms and two water O atoms. Each Pb2+ ion is also coordinated by two carboxylate O atoms and three water O atoms, leading to a highly irregular around Pb2+. The dimers are interconnected by hydrogen bonds between coordinated and uncoordinated water molecules and the carboxylate O atoms. O—H⋯N interactions are also present.
Related literature
For the ). Centrosymmetric dimeric molecules were reported in the structure of a calcium(II) complex with pyridazine-3-dicarboxylate and water ligands (Starosta & Leciejewicz, 2007) and an uranyl complex with the same ligands (Leciejewicz & Starosta, (2009). Each dimer shows a different bridging mode.
of pyridazine-4-carboxylic acid hydrochloride, see: Starosta & Leciejewicz (2008Experimental
Crystal data
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Data collection
Refinement
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Data collection: KM-4 Software (Kuma, 1996); cell KM-4 Software; data reduction: DATAPROC (Kuma, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.
Supporting information
https://doi.org/10.1107/S1600536809039658/bv2128sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536809039658/bv2128Isup2.hkl
2 Mmol of pyridazine-4-carboxylic acid were dissolved in 100 ml of hot water and boiled for two hours with small excess of Pb(OH)2. After cooling to room temperature the mixture was filtered and left to crystallize. Few days later colorless single crystals were found in the mother liquid. They were separated, washed with cold ethanol and dried in air.
H atoms attached to pyridazine-ring C atoms were positioned geometrically and refined with a riding model using AFIX43 instruction. The positions of water H atoms were initially located from Fourier maps and refined isotropically with restraints on O—H distance (0.86 Å) and H—O—H angle.
# Used for convenience to store draft or replaced versions
of the abstract, comment etc. Its contents will not be output#==============================================================================
Data collection: KM-4 Software (Kuma, 1996); cell
KM-4 Software (Kuma, 1996); data reduction: DATAPROC (Kuma,2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).Fig. 1. A dimer of (1) with atom labelling scheme and 50% probability displacement ellipsoids. | |
Fig. 2. Packing diagram of the structure. |
[Pb2(C5H3N2O2)4(H2O)6]·2H2O | Z = 1 |
Mr = 1086.92 | F(000) = 516 |
Triclinic, P1 | Dx = 2.283 Mg m−3 |
a = 7.0762 (14) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 9.2967 (19) Å | Cell parameters from 25 reflections |
c = 12.830 (3) Å | θ = 6–15° |
α = 92.05 (3)° | µ = 10.73 mm−1 |
β = 105.13 (3)° | T = 293 K |
γ = 102.85 (3)° | Plate, colourless |
V = 790.4 (3) Å3 | 0.35 × 0.18 × 0.03 mm |
Kuma KM-4 four-circle diffractometer | 3958 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.016 |
Graphite monochromator | θmax = 30.2°, θmin = 1.7° |
Profile data from ω/2θ scans | h = 0→9 |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008) | k = −13→12 |
Tmin = 0.254, Tmax = 0.762 | l = −18→16 |
4862 measured reflections | 3 standard reflections every 200 reflections |
4512 independent reflections | intensity decay: 1.2% |
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)] = 0.045 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.122 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.06 | w = 1/[σ2(Fo2) + (0.1029P)2] where P = (Fo2 + 2Fc2)/3 |
4512 reflections | (Δ/σ)max = 0.002 |
253 parameters | Δρmax = 5.63 e Å−3 |
15 restraints | Δρmin = −3.77 e Å−3 |
[Pb2(C5H3N2O2)4(H2O)6]·2H2O | γ = 102.85 (3)° |
Mr = 1086.92 | V = 790.4 (3) Å3 |
Triclinic, P1 | Z = 1 |
a = 7.0762 (14) Å | Mo Kα radiation |
b = 9.2967 (19) Å | µ = 10.73 mm−1 |
c = 12.830 (3) Å | T = 293 K |
α = 92.05 (3)° | 0.35 × 0.18 × 0.03 mm |
β = 105.13 (3)° |
Kuma KM-4 four-circle diffractometer | 3958 reflections with I > 2σ(I) |
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2008) | Rint = 0.016 |
Tmin = 0.254, Tmax = 0.762 | 3 standard reflections every 200 reflections |
4862 measured reflections | intensity decay: 1.2% |
4512 independent reflections |
R[F2 > 2σ(F2)] = 0.045 | 15 restraints |
wR(F2) = 0.122 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.06 | Δρmax = 5.63 e Å−3 |
4512 reflections | Δρmin = −3.77 e Å−3 |
253 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 | ||
Pb1 | 0.11555 (3) | 0.048890 (18) | 0.675973 (14) | 0.02300 (9) | |
O11 | 0.4666 (8) | 0.6974 (5) | 0.6607 (4) | 0.0360 (10) | |
O4 | −0.2317 (7) | 0.0086 (5) | 0.5150 (4) | 0.0309 (9) | |
O21 | 0.2153 (8) | 0.1496 (5) | 0.8788 (4) | 0.0387 (11) | |
O1 | 0.3206 (8) | −0.1283 (6) | 0.7946 (4) | 0.0395 (11) | |
H11 | 0.430 (8) | −0.075 (11) | 0.838 (5) | 0.047* | |
H12 | 0.347 (11) | −0.155 (10) | 0.736 (4) | 0.047* | |
N12 | 0.1246 (8) | 0.2794 (5) | 0.5304 (4) | 0.0265 (9) | |
N11 | 0.0425 (8) | 0.2525 (5) | 0.4237 (4) | 0.0280 (10) | |
O22 | 0.0922 (10) | 0.3005 (6) | 0.7692 (4) | 0.0452 (13) | |
O12 | 0.4408 (7) | 0.7751 (4) | 0.4972 (4) | 0.0331 (9) | |
C17 | 0.4044 (8) | 0.6811 (6) | 0.5601 (5) | 0.0247 (10) | |
C14 | 0.2716 (7) | 0.5309 (5) | 0.5091 (4) | 0.0208 (9) | |
C13 | 0.2351 (9) | 0.4143 (6) | 0.5710 (5) | 0.0249 (10) | |
H13 | 0.2916 | 0.4317 | 0.6458 | 0.030* | |
C15 | 0.1807 (9) | 0.5029 (6) | 0.3995 (5) | 0.0273 (11) | |
H15 | 0.1940 | 0.5769 | 0.3532 | 0.033* | |
C16 | 0.0682 (10) | 0.3600 (7) | 0.3606 (5) | 0.0309 (12) | |
H16 | 0.0079 | 0.3389 | 0.2863 | 0.037* | |
C24 | 0.2220 (9) | 0.3860 (6) | 0.9548 (5) | 0.0273 (11) | |
C27 | 0.1684 (10) | 0.2701 (6) | 0.8588 (5) | 0.0297 (11) | |
O5 | 0.7080 (10) | 0.0331 (7) | 0.9439 (4) | 0.0471 (13) | |
H51 | 0.753 (16) | 0.123 (4) | 0.975 (6) | 0.057* | |
H52 | 0.682 (16) | −0.024 (7) | 0.993 (5) | 0.057* | |
N21 | 0.3150 (10) | 0.6062 (7) | 1.1197 (5) | 0.0385 (13) | |
N22 | 0.2595 (11) | 0.6394 (6) | 1.0184 (6) | 0.0391 (13) | |
C25 | 0.2804 (11) | 0.3556 (7) | 1.0582 (5) | 0.0342 (13) | |
H23 | 0.2907 | 0.2606 | 1.0748 | 0.041* | |
C23 | 0.2131 (11) | 0.5332 (7) | 0.9376 (5) | 0.0325 (12) | |
H25 | 0.1731 | 0.5571 | 0.8667 | 0.039* | |
C26 | 0.3247 (13) | 0.4707 (9) | 1.1396 (6) | 0.0396 (15) | |
H26 | 0.3631 | 0.4503 | 1.2115 | 0.048* | |
O3 | 0.4919 (9) | 0.1749 (7) | 0.7070 (4) | 0.0449 (12) | |
O2 | −0.1694 (9) | −0.0786 (7) | 0.7638 (5) | 0.0490 (14) | |
H41 | −0.277 (8) | 0.082 (6) | 0.533 (5) | 0.07 (3)* | |
H42 | −0.316 (12) | −0.072 (6) | 0.521 (10) | 0.07 (3)* | |
H31 | 0.529 (18) | 0.231 (10) | 0.661 (6) | 0.07 (4)* | |
H32 | 0.557 (16) | 0.215 (11) | 0.771 (3) | 0.08 (4)* | |
H21 | −0.172 (17) | −0.018 (9) | 0.815 (6) | 0.05 (3)* | |
H22 | −0.259 (10) | −0.160 (6) | 0.740 (7) | 0.04 (2)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Pb1 | 0.02442 (13) | 0.01967 (12) | 0.02294 (13) | 0.00112 (8) | 0.00730 (9) | −0.00286 (7) |
O11 | 0.040 (2) | 0.026 (2) | 0.032 (2) | −0.0024 (18) | 0.0027 (19) | −0.0031 (17) |
O4 | 0.029 (2) | 0.0177 (18) | 0.044 (3) | 0.0019 (15) | 0.0105 (19) | 0.0037 (16) |
O21 | 0.049 (3) | 0.029 (2) | 0.035 (2) | 0.010 (2) | 0.008 (2) | −0.0061 (18) |
O1 | 0.041 (3) | 0.039 (3) | 0.039 (3) | 0.012 (2) | 0.010 (2) | −0.003 (2) |
N12 | 0.031 (2) | 0.0161 (19) | 0.032 (2) | 0.0016 (17) | 0.012 (2) | 0.0006 (17) |
N11 | 0.032 (2) | 0.0169 (19) | 0.032 (2) | 0.0005 (17) | 0.009 (2) | −0.0032 (17) |
O22 | 0.069 (4) | 0.039 (3) | 0.025 (2) | 0.016 (3) | 0.007 (2) | −0.0038 (19) |
O12 | 0.036 (2) | 0.0166 (17) | 0.046 (3) | −0.0025 (16) | 0.016 (2) | 0.0023 (16) |
C17 | 0.022 (2) | 0.015 (2) | 0.036 (3) | 0.0028 (17) | 0.009 (2) | −0.0044 (18) |
C14 | 0.019 (2) | 0.0133 (19) | 0.031 (3) | 0.0033 (16) | 0.0100 (19) | −0.0011 (17) |
C13 | 0.025 (2) | 0.020 (2) | 0.028 (3) | 0.0035 (19) | 0.006 (2) | 0.0020 (19) |
C15 | 0.030 (3) | 0.019 (2) | 0.033 (3) | 0.003 (2) | 0.010 (2) | 0.006 (2) |
C16 | 0.032 (3) | 0.024 (3) | 0.030 (3) | 0.000 (2) | 0.003 (2) | −0.002 (2) |
C24 | 0.032 (3) | 0.023 (2) | 0.026 (3) | 0.005 (2) | 0.007 (2) | −0.0055 (19) |
C27 | 0.038 (3) | 0.024 (2) | 0.027 (3) | 0.004 (2) | 0.011 (2) | −0.006 (2) |
O5 | 0.064 (4) | 0.042 (3) | 0.039 (3) | 0.016 (3) | 0.017 (3) | 0.001 (2) |
N21 | 0.040 (3) | 0.037 (3) | 0.034 (3) | 0.004 (2) | 0.009 (2) | −0.013 (2) |
N22 | 0.048 (3) | 0.025 (2) | 0.042 (3) | 0.009 (2) | 0.010 (3) | −0.005 (2) |
C25 | 0.048 (4) | 0.031 (3) | 0.025 (3) | 0.013 (3) | 0.012 (3) | 0.001 (2) |
C23 | 0.044 (3) | 0.028 (3) | 0.027 (3) | 0.013 (2) | 0.009 (2) | 0.003 (2) |
C26 | 0.052 (4) | 0.042 (4) | 0.024 (3) | 0.010 (3) | 0.009 (3) | −0.006 (2) |
O3 | 0.043 (3) | 0.051 (3) | 0.025 (2) | −0.016 (2) | 0.008 (2) | −0.007 (2) |
O2 | 0.045 (3) | 0.053 (3) | 0.042 (3) | −0.012 (2) | 0.023 (2) | −0.011 (2) |
Pb1—O3 | 2.578 (6) | C13—H13 | 0.9300 |
Pb1—O21 | 2.593 (5) | C15—C16 | 1.386 (8) |
Pb1—O2 | 2.638 (6) | C15—H15 | 0.9300 |
Pb1—O22 | 2.647 (5) | C16—H16 | 0.9300 |
Pb1—O1 | 2.688 (6) | C24—C25 | 1.343 (9) |
Pb1—O4 | 2.707 (5) | C24—C23 | 1.406 (8) |
O11—C17 | 1.242 (8) | C24—C27 | 1.517 (8) |
O4—H41 | 0.86 (2) | O5—H51 | 0.86 (2) |
O4—H42 | 0.87 (2) | O5—H52 | 0.87 (2) |
O21—C27 | 1.254 (8) | N21—C26 | 1.308 (10) |
O1—H11 | 0.86 (2) | N21—N22 | 1.324 (10) |
O1—H12 | 0.86 (2) | N22—C23 | 1.328 (8) |
N12—C13 | 1.327 (7) | C25—C26 | 1.390 (9) |
N12—N11 | 1.331 (7) | C25—H23 | 0.9300 |
N11—C16 | 1.320 (8) | C23—H25 | 0.9300 |
O22—C27 | 1.208 (8) | C26—H26 | 0.9300 |
O12—C17 | 1.241 (7) | O3—H31 | 0.86 (2) |
C17—C14 | 1.514 (7) | O3—H32 | 0.86 (2) |
C14—C15 | 1.373 (8) | O2—H21 | 0.86 (2) |
C14—C13 | 1.385 (7) | O2—H22 | 0.86 (2) |
O3—Pb1—O21 | 79.05 (17) | N12—C13—H13 | 118.0 |
O3—Pb1—O2 | 146.72 (18) | C14—C13—H13 | 118.0 |
O21—Pb1—O2 | 70.88 (18) | C14—C15—C16 | 117.4 (5) |
O3—Pb1—O22 | 85.5 (2) | C14—C15—H15 | 121.3 |
O21—Pb1—O22 | 49.16 (16) | C16—C15—H15 | 121.3 |
O2—Pb1—O22 | 85.5 (2) | N11—C16—C15 | 123.2 (6) |
O3—Pb1—O1 | 74.2 (2) | N11—C16—H16 | 118.4 |
O21—Pb1—O1 | 71.28 (16) | C15—C16—H16 | 118.4 |
O2—Pb1—O1 | 82.8 (2) | C25—C24—C23 | 117.0 (5) |
O22—Pb1—O1 | 119.77 (16) | C25—C24—C27 | 123.0 (6) |
O3—Pb1—O4 | 137.65 (16) | C23—C24—C27 | 120.1 (6) |
O21—Pb1—O4 | 132.46 (16) | O22—C27—O21 | 124.6 (6) |
O2—Pb1—O4 | 75.25 (18) | O22—C27—C24 | 119.1 (6) |
O22—Pb1—O4 | 96.49 (16) | O21—C27—C24 | 116.3 (6) |
O1—Pb1—O4 | 135.76 (15) | H51—O5—H52 | 107 (3) |
Pb1—O4—H41 | 100.9 (17) | C26—N21—N22 | 120.3 (6) |
Pb1—O4—H42 | 110 (8) | N21—N22—C23 | 119.1 (6) |
H41—O4—H42 | 107 (3) | C24—C25—C26 | 117.9 (6) |
C27—O21—Pb1 | 93.8 (4) | C24—C25—H23 | 121.1 |
Pb1—O1—H11 | 110 (8) | C26—C25—H23 | 121.1 |
Pb1—O1—H12 | 87 (7) | N22—C23—C24 | 122.7 (6) |
H11—O1—H12 | 109 (3) | N22—C23—H25 | 118.7 |
C13—N12—N11 | 118.9 (5) | C24—C23—H25 | 118.7 |
C16—N11—N12 | 119.9 (5) | N21—C26—C25 | 123.0 (7) |
C27—O22—Pb1 | 92.3 (4) | N21—C26—H26 | 118.5 |
O12—C17—O11 | 126.7 (5) | C25—C26—H26 | 118.5 |
O12—C17—C14 | 116.7 (5) | Pb1—O3—H31 | 120 (8) |
O11—C17—C14 | 116.6 (5) | Pb1—O3—H32 | 117 (8) |
C15—C14—C13 | 116.5 (5) | H31—O3—H32 | 109 (4) |
C15—C14—C17 | 122.0 (5) | Pb1—O2—H21 | 108 (7) |
C13—C14—C17 | 121.5 (5) | Pb1—O2—H22 | 127 (6) |
N12—C13—C14 | 124.0 (5) | H21—O2—H22 | 124 (10) |
D—H···A | D—H | H···A | D···A | D—H···A |
O4—H41···O12i | 0.86 (2) | 1.93 (2) | 2.736 (6) | 154 (4) |
O4—H42···O12ii | 0.87 (2) | 1.92 (4) | 2.754 (6) | 161 (11) |
O1—H11···O5 | 0.86 (2) | 2.08 (3) | 2.943 (9) | 174 (10) |
O1—H12···O11iii | 0.86 (2) | 2.09 (6) | 2.849 (7) | 146 (9) |
O5—H51···N22iv | 0.86 (2) | 2.23 (5) | 3.013 (8) | 151 (9) |
O5—H52···O21v | 0.87 (2) | 2.12 (6) | 2.897 (8) | 149 (10) |
O3—H31···O12vi | 0.86 (2) | 2.09 (7) | 2.819 (7) | 142 (10) |
O3—H32···N21iv | 0.86 (2) | 2.01 (6) | 2.794 (7) | 151 (10) |
O2—H21···O5vii | 0.86 (2) | 2.13 (5) | 2.906 (8) | 150 (9) |
O2—H22···O11ii | 0.86 (2) | 2.07 (4) | 2.891 (7) | 159 (9) |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) x−1, y−1, z; (iii) x, y−1, z; (iv) −x+1, −y+1, −z+2; (v) −x+1, −y, −z+2; (vi) −x+1, −y+1, −z+1; (vii) x−1, y, z. |
Experimental details
Crystal data | |
Chemical formula | [Pb2(C5H3N2O2)4(H2O)6]·2H2O |
Mr | 1086.92 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 7.0762 (14), 9.2967 (19), 12.830 (3) |
α, β, γ (°) | 92.05 (3), 105.13 (3), 102.85 (3) |
V (Å3) | 790.4 (3) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 10.73 |
Crystal size (mm) | 0.35 × 0.18 × 0.03 |
Data collection | |
Diffractometer | Kuma KM-4 four-circle |
Absorption correction | Analytical (CrysAlis RED; Oxford Diffraction, 2008) |
Tmin, Tmax | 0.254, 0.762 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4862, 4512, 3958 |
Rint | 0.016 |
(sin θ/λ)max (Å−1) | 0.707 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.122, 1.06 |
No. of reflections | 4512 |
No. of parameters | 253 |
No. of restraints | 15 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 5.63, −3.77 |
Computer programs: KM-4 Software (Kuma, 1996), DATAPROC (Kuma,2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
O4—H41···O12i | 0.86 (2) | 1.93 (2) | 2.736 (6) | 154 (4) |
O4—H42···O12ii | 0.87 (2) | 1.92 (4) | 2.754 (6) | 161 (11) |
O1—H11···O5 | 0.86 (2) | 2.08 (3) | 2.943 (9) | 174 (10) |
O1—H12···O11iii | 0.86 (2) | 2.09 (6) | 2.849 (7) | 146 (9) |
O5—H51···N22iv | 0.86 (2) | 2.23 (5) | 3.013 (8) | 151 (9) |
O5—H52···O21v | 0.87 (2) | 2.12 (6) | 2.897 (8) | 149 (10) |
O3—H31···O12vi | 0.86 (2) | 2.09 (7) | 2.819 (7) | 142 (10) |
O3—H32···N21iv | 0.86 (2) | 2.01 (6) | 2.794 (7) | 151 (10) |
O2—H21···O5vii | 0.86 (2) | 2.13 (5) | 2.906 (8) | 150 (9) |
O2—H22···O11ii | 0.86 (2) | 2.07 (4) | 2.891 (7) | 159 (9) |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) x−1, y−1, z; (iii) x, y−1, z; (iv) −x+1, −y+1, −z+2; (v) −x+1, −y, −z+2; (vi) −x+1, −y+1, −z+1; (vii) x−1, y, z. |
References
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Kuma (2001). DATAPROC. Kuma Diffraction Ltd, Wrocław, Poland. Google Scholar
Leciejewicz, J. & Starosta, W. (2009). Acta Cryst. E65, m94. Web of Science CSD CrossRef IUCr Journals Google Scholar
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Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Starosta, W. & Leciejewicz, J. (2007). Acta Cryst. E63, m1662–m1663. Web of Science CSD CrossRef IUCr Journals Google Scholar
Starosta, W. & Leciejewicz, J. (2008). Acta Cryst. E64, o461. Web of Science CSD CrossRef IUCr Journals Google Scholar
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The structure of the title compound (I) is built of dimeric molecules (Fig.1) in which two symmetry related, nine-coordinate Pb2+ ions are chelated by two pairs of pyridazine-4-carboxylate anions via their both hetero-ring atoms, each pair showing different chelating mode: one uses both its hetero-ring N atoms to bridge the metal ions, its deprotonated carboxylate O atoms are left inactive in coordination, the other coordinates the Pb2+ions only via carboxylate groups which act as bidentate. In addition, the Pb2+ ions are bridged by a pair of water molecules. Three coordinated water O atoms complete the coordination enviroment of Pb2+ ions. The coordination geometry around a metal ion is highly irregular. Pyridazine rings are planar with r.m.s. 0.0081 (2)Å (ligand 1) and 0.0030 (2)Å (ligand 2). The coordinated (C27/O21/O22) and non-coordinated (C17/O11/O12) carboxylic groups make dihedral angles of 5.6 (1)° and 11.9 (1)° with their respective pyridazine rings. A packing diagram of (I) displayed in Fig.2 shows how the dimers are linked by a network of hydrogen bonds. Their relevant geometrical parameters are listed in Table 1.