The title compound, [Pb(C
8H
4O
4)(H
2O)]
n, forms as an insoluble product in the reaction of sodium terephthalate(2−) with Pb(NO
3)
2 in water. Analysis has shown that the crystal structure is centrosymmetric, with the asymmetric unit containing one formula unit. The lead geometry is hemidirected seven-coordinate, with both monodentate and bidentate carboxylate coordination modes present. The combination of hydrogen bonds and coordination bonds produces a three-dimensional structure, including the first example, in a lead complex, of the common metal-coordinated carboxylate/water
(6) graph-set motif.
Supporting information
CCDC reference: 233113
X-ray quality colourless crystals of (I) were obtained in quantitaive yield by diffusing together separate aqueous solutions (1:1 ratio) of lead(II) nitrate and sodium terephthalate (Na2TA; formed from the reaction of H2TA with two equivalents of NaOH in water). IR (KBr, νmax/cm−1): 3425 (br, OH), 3063 and 2924 (aromatic C—H), 1524 (asymmetric CO2−), 1358 (symmetric CO2−), 818 and 748 (aromatic C—H), 521.
Aromatic H atoms were placed geometrically (C—H = 0.95 Å) and treated using a riding model, while the coordinates of the water H atoms were found in a difference Fourier map and subsequently refined using geometric restraints. Uiso(H) values were set to 1.2Ueq(C) for aryl H atoms and 1.5Ueq(O) for O-bound H atoms.
Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2000); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and local programs.
Poly[lead(II)-µ
2-aqua-µ
3-terephthalato]
top
Crystal data top
[Pb(C8H4O4)(H2O)] | F(000) = 704 |
Mr = 389.32 | Dx = 3.079 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 3310 reflections |
a = 10.6661 (7) Å | θ = 3.3–28.9° |
b = 7.5042 (5) Å | µ = 20.08 mm−1 |
c = 11.1260 (8) Å | T = 150 K |
β = 109.404 (2)° | Column, colourless |
V = 839.95 (10) Å3 | 0.24 × 0.09 × 0.06 mm |
Z = 4 | |
Data collection top
Bruker SMART1000 CCD area detector diffractometer | 1637 independent reflections |
Radiation source: sealed tube | 1496 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.033 |
ω rotation with narrow frames scans | θmax = 26.0°, θmin = 2.0° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2001) | h = −8→13 |
Tmin = 0.068, Tmax = 0.300 | k = −9→9 |
4408 measured reflections | l = −13→10 |
Refinement top
Refinement on F2 | Hydrogen site location: Geom except OH coords refined with restraints |
Least-squares matrix: full | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.023 | w = 1/[σ2(Fo2) + (0.0297P)2 + 0.2788P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.057 | (Δ/σ)max = 0.002 |
S = 1.04 | Δρmax = 1.63 e Å−3 |
1637 reflections | Δρmin = −2.11 e Å−3 |
134 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
7 restraints | Extinction coefficient: 0.0017 (2) |
Primary atom site location: structure-invariant direct methods | |
Crystal data top
[Pb(C8H4O4)(H2O)] | V = 839.95 (10) Å3 |
Mr = 389.32 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 10.6661 (7) Å | µ = 20.08 mm−1 |
b = 7.5042 (5) Å | T = 150 K |
c = 11.1260 (8) Å | 0.24 × 0.09 × 0.06 mm |
β = 109.404 (2)° | |
Data collection top
Bruker SMART1000 CCD area detector diffractometer | 1637 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2001) | 1496 reflections with I > 2σ(I) |
Tmin = 0.068, Tmax = 0.300 | Rint = 0.033 |
4408 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.023 | 7 restraints |
wR(F2) = 0.057 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.04 | Δρmax = 1.63 e Å−3 |
1637 reflections | Δρmin = −2.11 e Å−3 |
134 parameters | |
Special details top
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 (Å2) top | x | y | z | Uiso*/Ueq | |
Pb1 | 1.031682 (18) | 0.02918 (3) | 0.699144 (18) | 0.01008 (11) | |
C1 | 0.6240 (5) | 0.1435 (7) | 0.7082 (5) | 0.0099 (11) | |
C2 | 0.5292 (5) | 0.0668 (7) | 0.7534 (5) | 0.0104 (11) | |
H2 | 0.5554 | 0.0156 | 0.8361 | 0.012* | |
C3 | 0.3961 (5) | 0.0655 (8) | 0.6770 (6) | 0.0146 (12) | |
H3 | 0.3316 | 0.0138 | 0.7081 | 0.018* | |
C4 | 0.3570 (5) | 0.1393 (7) | 0.5557 (5) | 0.0099 (11) | |
C5 | 0.4509 (5) | 0.2214 (7) | 0.5129 (5) | 0.0118 (11) | |
H5 | 0.4237 | 0.2777 | 0.4318 | 0.014* | |
C6 | 0.5846 (5) | 0.2218 (7) | 0.5879 (5) | 0.0119 (11) | |
H6 | 0.6487 | 0.2754 | 0.5571 | 0.014* | |
C7 | 0.7671 (5) | 0.1342 (7) | 0.7905 (5) | 0.0110 (11) | |
O1 | 0.8542 (3) | 0.1999 (5) | 0.7482 (3) | 0.0122 (8) | |
O2 | 0.7939 (4) | 0.0603 (5) | 0.8988 (4) | 0.0168 (9) | |
C8 | 0.2154 (5) | 0.1169 (7) | 0.4704 (5) | 0.0140 (12) | |
O3 | 0.1400 (4) | 0.0149 (5) | 0.5068 (4) | 0.0157 (9) | |
O4 | 0.1760 (3) | 0.1879 (5) | 0.3620 (3) | 0.0154 (8) | |
O5 | 1.0015 (3) | 0.3415 (5) | 0.6003 (3) | 0.0131 (8) | |
H5A | 0.936 (3) | 0.354 (3) | 0.5219 (15) | 0.020* | |
H5B | 1.063 (3) | 0.381 (3) | 0.568 (3) | 0.020* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Pb1 | 0.00812 (14) | 0.01156 (16) | 0.00969 (16) | −0.00022 (7) | 0.00181 (9) | −0.00037 (7) |
C1 | 0.011 (2) | 0.008 (3) | 0.009 (3) | −0.001 (2) | 0.001 (2) | −0.002 (2) |
C2 | 0.010 (3) | 0.016 (3) | 0.005 (3) | −0.002 (2) | 0.002 (2) | −0.001 (2) |
C3 | 0.010 (3) | 0.018 (3) | 0.019 (3) | 0.001 (2) | 0.009 (2) | 0.003 (2) |
C4 | 0.010 (2) | 0.007 (3) | 0.012 (3) | 0.002 (2) | 0.002 (2) | 0.000 (2) |
C5 | 0.014 (3) | 0.013 (3) | 0.007 (3) | 0.005 (2) | 0.002 (2) | −0.001 (2) |
C6 | 0.012 (2) | 0.010 (3) | 0.014 (3) | 0.001 (2) | 0.006 (2) | 0.001 (2) |
C7 | 0.007 (2) | 0.010 (3) | 0.016 (3) | 0.001 (2) | 0.004 (2) | −0.006 (2) |
O1 | 0.0081 (17) | 0.013 (2) | 0.016 (2) | 0.0005 (15) | 0.0042 (15) | 0.0014 (16) |
O2 | 0.0120 (19) | 0.022 (2) | 0.015 (2) | 0.0007 (16) | 0.0024 (16) | 0.0019 (17) |
C8 | 0.015 (3) | 0.013 (3) | 0.012 (3) | 0.001 (2) | 0.002 (2) | −0.004 (2) |
O3 | 0.010 (2) | 0.026 (2) | 0.013 (2) | −0.0062 (16) | 0.0074 (17) | −0.0033 (16) |
O4 | 0.0125 (18) | 0.018 (2) | 0.012 (2) | −0.0003 (15) | −0.0002 (15) | −0.0006 (16) |
O5 | 0.0110 (18) | 0.017 (2) | 0.0106 (19) | −0.0012 (15) | 0.0030 (15) | 0.0013 (16) |
Geometric parameters (Å, º) top
Pb1—O1 | 2.492 (3) | C3—H3 | 0.9500 |
Pb1—O1i | 2.731 (4) | C4—C5 | 1.388 (7) |
Pb1—O3ii | 2.434 (4) | C4—C8 | 1.503 (7) |
Pb1—O3iii | 2.751 (4) | C5—C6 | 1.393 (7) |
Pb1—O4ii | 2.650 (4) | C5—H5 | 0.9500 |
Pb1—O5 | 2.563 (4) | C6—H6 | 0.9500 |
Pb1—O5i | 2.759 (4) | C7—O2 | 1.269 (7) |
C1—C6 | 1.393 (7) | C7—O1 | 1.272 (6) |
C1—C2 | 1.394 (7) | C8—O4 | 1.256 (6) |
C1—C7 | 1.498 (6) | C8—O3 | 1.270 (7) |
C2—C3 | 1.391 (7) | O5—H5A | 0.92 (2) |
C2—H2 | 0.9500 | O5—H5B | 0.90 (2) |
C3—C4 | 1.388 (8) | | |
| | | |
O3ii—Pb1—O1 | 83.53 (12) | C2—C3—H3 | 119.8 |
O3ii—Pb1—O5 | 76.84 (12) | C5—C4—C3 | 119.5 (5) |
O1—Pb1—O5 | 68.13 (11) | C5—C4—C8 | 121.4 (5) |
O3ii—Pb1—O4ii | 51.07 (12) | C3—C4—C8 | 118.9 (5) |
O1—Pb1—O4ii | 74.99 (12) | C4—C5—C6 | 120.5 (5) |
O5—Pb1—O4ii | 118.47 (11) | C4—C5—H5 | 119.8 |
O3ii—Pb1—O1i | 102.80 (12) | C6—C5—H5 | 119.8 |
O1—Pb1—O1i | 137.33 (9) | C5—C6—C1 | 119.8 (5) |
O5—Pb1—O1i | 154.54 (11) | C5—C6—H6 | 120.1 |
O4ii—Pb1—O1i | 76.94 (11) | C1—C6—H6 | 120.1 |
O3ii—Pb1—O3iii | 68.98 (15) | O2—C7—O1 | 124.0 (5) |
O1—Pb1—O3iii | 137.41 (12) | O2—C7—C1 | 117.6 (5) |
O5—Pb1—O3iii | 74.18 (11) | O1—C7—C1 | 118.5 (5) |
O4ii—Pb1—O3iii | 107.91 (12) | C7—O1—Pb1 | 125.7 (3) |
O1i—Pb1—O3iii | 81.90 (11) | C7—O1—Pb1iv | 126.8 (3) |
O3ii—Pb1—O5i | 115.69 (12) | Pb1—O1—Pb1iv | 101.25 (11) |
O1—Pb1—O5i | 76.97 (11) | O4—C8—O3 | 121.1 (5) |
O5—Pb1—O5i | 141.45 (10) | O4—C8—C4 | 120.3 (5) |
O4ii—Pb1—O5i | 64.72 (11) | O3—C8—C4 | 118.4 (5) |
O1i—Pb1—O5i | 62.12 (11) | C8—O3—Pb1ii | 98.0 (3) |
O3iii—Pb1—O5i | 144.00 (11) | C8—O3—Pb1v | 134.3 (3) |
C6—C1—C2 | 119.8 (5) | Pb1ii—O3—Pb1v | 111.02 (15) |
C6—C1—C7 | 121.8 (5) | C8—O4—Pb1ii | 88.3 (3) |
C2—C1—C7 | 118.3 (5) | Pb1—O5—Pb1iv | 98.71 (11) |
C3—C2—C1 | 119.9 (5) | Pb1—O5—H5A | 116.7 (16) |
C3—C2—H2 | 120.1 | Pb1iv—O5—H5A | 116.9 (15) |
C1—C2—H2 | 120.1 | Pb1—O5—H5B | 117.7 (16) |
C4—C3—C2 | 120.5 (5) | Pb1iv—O5—H5B | 117.7 (16) |
C4—C3—H3 | 119.8 | H5A—O5—H5B | 90.7 (17) |
| | | |
C6—C1—C2—C3 | 1.4 (8) | O5i—Pb1—O1—C7 | −32.0 (4) |
C7—C1—C2—C3 | −177.0 (5) | O3ii—Pb1—O1—Pb1iv | −120.14 (13) |
C1—C2—C3—C4 | 0.3 (8) | O5—Pb1—O1—Pb1iv | −41.75 (11) |
C2—C3—C4—C5 | −2.7 (8) | O4ii—Pb1—O1—Pb1iv | −171.51 (14) |
C2—C3—C4—C8 | 173.0 (5) | O1i—Pb1—O1—Pb1iv | 137.98 (14) |
C3—C4—C5—C6 | 3.4 (8) | O3iii—Pb1—O1—Pb1iv | −71.20 (18) |
C8—C4—C5—C6 | −172.2 (5) | O5i—Pb1—O1—Pb1iv | 121.56 (12) |
C4—C5—C6—C1 | −1.7 (8) | C5—C4—C8—O4 | −7.0 (8) |
C2—C1—C6—C5 | −0.7 (8) | C3—C4—C8—O4 | 177.4 (5) |
C7—C1—C6—C5 | 177.6 (5) | C5—C4—C8—O3 | 168.1 (5) |
C6—C1—C7—O2 | −179.9 (5) | C3—C4—C8—O3 | −7.6 (7) |
C2—C1—C7—O2 | −1.6 (7) | O4—C8—O3—Pb1ii | 13.2 (6) |
C6—C1—C7—O1 | −0.1 (8) | C4—C8—O3—Pb1ii | −161.8 (4) |
C2—C1—C7—O1 | 178.2 (5) | O4—C8—O3—Pb1v | −116.9 (5) |
O2—C7—O1—Pb1 | 64.4 (6) | C4—C8—O3—Pb1v | 68.1 (6) |
C1—C7—O1—Pb1 | −115.4 (4) | O3—C8—O4—Pb1ii | −12.0 (5) |
O2—C7—O1—Pb1iv | −82.5 (6) | C4—C8—O4—Pb1ii | 162.9 (4) |
C1—C7—O1—Pb1iv | 97.7 (5) | O3ii—Pb1—O5—Pb1iv | 129.07 (13) |
O3ii—Pb1—O1—C7 | 86.3 (4) | O1—Pb1—O5—Pb1iv | 40.84 (10) |
O5—Pb1—O1—C7 | 164.7 (4) | O4ii—Pb1—O5—Pb1iv | 98.49 (13) |
O4ii—Pb1—O1—C7 | 35.0 (4) | O1i—Pb1—O5—Pb1iv | −138.7 (2) |
O1i—Pb1—O1—C7 | −15.6 (4) | O3iii—Pb1—O5—Pb1iv | −159.39 (14) |
O3iii—Pb1—O1—C7 | 135.3 (4) | O5i—Pb1—O5—Pb1iv | 14.2 (2) |
Symmetry codes: (i) −x+2, y−1/2, −z+3/2; (ii) −x+1, −y, −z+1; (iii) x+1, y, z; (iv) −x+2, y+1/2, −z+3/2; (v) x−1, y, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O5—H5B···O2iv | 0.90 (2) | 1.97 (2) | 2.728 (5) | 140 (2) |
O5—H5A···O2vi | 0.92 (2) | 1.79 (2) | 2.678 (5) | 160 (2) |
Symmetry codes: (iv) −x+2, y+1/2, −z+3/2; (vi) x, −y+1/2, z−1/2. |
Experimental details
Crystal data |
Chemical formula | [Pb(C8H4O4)(H2O)] |
Mr | 389.32 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 150 |
a, b, c (Å) | 10.6661 (7), 7.5042 (5), 11.1260 (8) |
β (°) | 109.404 (2) |
V (Å3) | 839.95 (10) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 20.08 |
Crystal size (mm) | 0.24 × 0.09 × 0.06 |
|
Data collection |
Diffractometer | Bruker SMART1000 CCD area detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2001) |
Tmin, Tmax | 0.068, 0.300 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4408, 1637, 1496 |
Rint | 0.033 |
(sin θ/λ)max (Å−1) | 0.617 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.023, 0.057, 1.04 |
No. of reflections | 1637 |
No. of parameters | 134 |
No. of restraints | 7 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 1.63, −2.11 |
Selected geometric parameters (Å, º) topPb1—O1 | 2.492 (3) | Pb1—O4ii | 2.650 (4) |
Pb1—O1i | 2.731 (4) | Pb1—O5 | 2.563 (4) |
Pb1—O3ii | 2.434 (4) | Pb1—O5i | 2.759 (4) |
Pb1—O3iii | 2.751 (4) | | |
| | | |
O1—Pb1—O5 | 68.13 (11) | O1—Pb1—O5i | 76.97 (11) |
O3ii—Pb1—O4ii | 51.07 (12) | O1i—Pb1—O5i | 62.12 (11) |
Symmetry codes: (i) −x+2, y−1/2, −z+3/2; (ii) −x+1, −y, −z+1; (iii) x+1, y, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O5—H5B···O2iv | 0.90 (2) | 1.97 (2) | 2.728 (5) | 140 (2) |
O5—H5A···O2v | 0.92 (2) | 1.79 (2) | 2.678 (5) | 160 (2) |
Symmetry codes: (iv) −x+2, y+1/2, −z+3/2; (v) x, −y+1/2, z−1/2. |
Authors to supply heading for this Table top | Range (CSD) | Mean (CSD) | Compound (I) |
O···O | 2.429–2.983 | 2.680 (4) | 2.728 (5) |
H(water)···O(carbox.) | 1.280–2.458 | 1.871 (8) | 1.97 (2) |
O—H···O | 130.29–179.74 | 157.0 (4) | 140 (2) |
M—carboxylate | 1.929–2.290 | 2.123 (4) | |
| 2.291–2.637 | 2.438 (7) | 2.492 (3) |
| 2.693–3.094 | 2.82 (3) | |
M—OH2 | 1.903–2.428 | 2.160 (5) | |
| 2.467–3.049 | 2.814 (19) | 2.759 (4) |
O—M—O | 65.75–81.80 | 74.6 (3) | 76.97 (11) |
| 82.78–106.20 | 91.0 (2) | |
Limits applied to the search of the Cambridge Structural Database (July 2003 update): O···O 2.0–3.5 Å, H(water)···O(carboxylate) 1.0–2.5 Å, O—H···O 120–180°. Redeterminations were included. Where more than one population range was obvious within the limits applied, the range and mean for each population are given. |
As part of our recent study of monovalent and divalent metal salts of terephthalic acid (benzene-1,4-dicarboxylic acid, H2TA; Dale & Elsegood, 2003a, 2003b), we have investigated the complexation of the TA2− anion to divalent lead, a known environmental pollutant (Shimoni-Livny et al., 1998). Previously, the PbII salt of trimesic acid (Foreman et al., 2000) was the only structurally characterized example of this cation complexed to the commonly used members of the benzenepolycarboxylic acid family, although PbII and PbIV-carboxylate complexes are well known in the literature, with 160 examples in the Cambridge Structural Database (CSD; Version 5.25, November 2003 update; Allen, 2002).
Attempts to produce single crystals of the desired coordination complex via the direct reaction of PbII with H2TA are hindered by the low solubility of both H2TA and the resulting PbII complex in water and organic solvents. However, the slow diffusion of separate aqueous solutions of Pb(NO3)2 and Na2TA (formed from the reaction of H2TA with two equivalents of NaOH) results in the formation of crystals of the title compound, PbTA(H2O), (I).
The asymmetric unit of (I) contains one formula unit. The PbII cation is seven-coordinate (Fig. 1), having a hemidirected coordination sphere (Shimoni-Livny et al., 1998). The water molecule asymmetrically bridges two symmetry-related PbII centres, and the remaining five coordination bonds on each Pb atom are completed by Pb–carboxylate interactions. Each PbII cation bonds to three symmetry-related TA2− anions via monodentate coordination, while bidentate coordination is observed for a fourth TA2− anion, having a bite angle of 51.07 (12)° [the CSD range for PbII or PbIV–(bidentate)carboxylate complexes is 45.82–58.33 °, mean 51.3 (2)°]. The monodentate Pb–carboxylate bond lengths in (I) lie in the range 2.492 (3)–2.751 (4) Å [mean 2.658 Å; the CSD range for all PbII or PbIV–carboxylate interactions (monodentate and bidentate) is 2.148–3.075 Å, mean 2.582 (8) Å] and the bidentate Pb–carboxylate bond lengths in (I) are 2.434 (4) and 2.650 (4) Å [mean 2.542 Å; the CSD range for bidentate PbII or PbIV–carboxylate interactions is 2.177–2.968 Å, mean 2.532 (15) Å]. The bridging water–Pb bond lengths average 2.661 Å [the CSD range for PbII or PbIV–OH2 bond lengths is 2.354–2.974 Å, mean 2.62 (2) Å].
The TA2− anion bridges four symmetry-related PbII centres, utilizing three of its O atoms, the fourth (O2) being involved in hydrogen bonding. While the TA2− anion bridges metal centres using both of its carboxylate groups in the majority of its divalent transition metal complexes [for example MgII, MnII and FeII (Kaduk, 2002); CdII (Michaelides et al., 1998); and ZnII (Edgar et al., 2001)], b contrast, in the structures of CuII (Kaduk, 2002), CaII (Dale & Elsegood, 2003a), and SrII and BaII (Groeneman & Atwood, 1999), the TA2− anions utilize only one carboxylate group for coordination, while the second forms hydrogen bonds with included water molecules.
The bridging of two PbII centres each by the unique water molecule and carboxy atom O1 creates four-membered rings in which the O—Pb—O bond angles are 68.13 (11) and 62.12 (11)° (Fig. 2 and Table 1). The combination of Pb—O coordination bonds (Table 1) and a carboxy–water O—H···O hydrogen bond (Table 2) results in the formation of a six-membered ring, which can be described by the graph set R11(6) (Etter, 1990; Etter & MacDonald, 1990; Bernstein et al., 1995). While a search of the CSD shows that the R11(6) carboxylate/metal/water motif has not yet been characterized in complexes containing lead, a total of 494 structures (containing any metal cation other than lead) do contain the motif [limits applied to the search: O···O = 2.0–3.5 Å, H···O = 1.0–2.5 Å and O—H···O = 120–180°]. The results of this search are shown in Table 3, and it can be seen that the geometry of the R11(6) motif in (I) shows good agreement with the literature examples. O—H···O hydrogen bonds (Table 2) between the water molecules and carboxyl groups also create R22(8) ring motifs (Fig. 2).
The three-dimensional network of coordination and hydrogen bonds in compound (I) (Fig. 3) results in a distance of approximately 3.7 Å between the centroids of the aromatic rings of adjacent, slightly offset, TA2− anions, which bridge the same two PbII centres. This leads to the non-planar geometry of the TA2− anions, the carboxy C atoms of which deviate (towards the PbII centres) from coplanarity with the aromatic ring by 0.080 (9) and 0.177 (9) Å for atoms C7 and C8, respectively.