Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270110029124/lg3036sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270110029124/lg3036Isup2.hkl | |
Portable Document Format (PDF) file https://doi.org/10.1107/S0108270110029124/lg3036sup3.pdf |
CCDC reference: 796056
For related literature, see: Barnett & Uchtman (1979); Brouca-Cabarrecq et al. (1996); Chen et al. (2009); Janiak (2003); Kitagawa et al. (2004); Liu et al. (2006); Llyukhin & Davidovich (1999); Luo & Xu (2006); O'Keeffe et al. (2000); Polyakova et al. (2001); Solans et al. (1985, 1987); Van Remoortere, Flynn, Boer & North (1971); Wang et al. (2008); Yaghi et al. (1997); Yi et al. (1998).
A mixture of Cd(NO3)2.4H2O (154 mg, 0.5 mmol) and ethylenediaminetetraacetic acid (186 mg, 0.5 mmol) in a 1:1 molar ratio in 14 ml of CH3CN/H2O (3:4 v/v) was introduced into a Parr Teflon-lined stainless steel vessel (20 ml). The vessel was sealed and heated to 413 K. The temperature was held for 2 d and then the mixture was left to cool to room temperature to obtain colourless block crystals. The crystalline product was filtered off, washed with CH3CN/H2O and dried at ambient temperature [yield 43% based on Cd(NO3)2.4H2O]. IR (KBr pellet, cm-1): 3436, 3108, 3076, 1642, 1559, 1481, 1426, 1363, 1197, 1129, 1078, 1032, 996, 879, 862, 673, 628, 545.
Methylene H atoms were placed in calculated positions and treated using a riding-model approximation [C—H = 0.97 Å and Uiso(H) = 1.2Ueq(C)]. H atoms bonded to O atoms were located in a difference map and were allowed to ride on their parent O atoms [O—H = 0.85 Å and Uiso(H) = 1.5Ueq(O)].
Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL97 (Sheldrick, 2008) and DIAMOND (Brandenburg, 2005); software used to prepare material for publication: SHELXTL97 (Sheldrick, 2008).
[Cd2(C10H12N2O8)(H2O)]·H2O | F(000) = 1064 |
Mr = 549.07 | Dx = 2.494 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 8.4640 (6) Å | Cell parameters from 9037 reflections |
b = 19.2334 (14) Å | θ = 2.5–28.2° |
c = 9.0134 (6) Å | µ = 2.97 mm−1 |
β = 94.680 (1)° | T = 296 K |
V = 1462.41 (18) Å3 | Block, colourless |
Z = 4 | 0.41 × 0.21 × 0.09 mm |
Bruker APEXII area-detector diffractometer | 3590 independent reflections |
Radiation source: fine-focus sealed tube | 3363 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.027 |
ω scans | θmax = 28.2°, θmin = 2.5° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −11→11 |
Tmin = 0.521, Tmax = 0.794 | k = −25→24 |
13303 measured reflections | l = −11→11 |
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)] = 0.026 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.073 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0305P)2 + 5.9512P] where P = (Fo2 + 2Fc2)/3 |
3590 reflections | (Δ/σ)max = 0.001 |
217 parameters | Δρmax = 0.51 e Å−3 |
0 restraints | Δρmin = −1.20 e Å−3 |
[Cd2(C10H12N2O8)(H2O)]·H2O | V = 1462.41 (18) Å3 |
Mr = 549.07 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 8.4640 (6) Å | µ = 2.97 mm−1 |
b = 19.2334 (14) Å | T = 296 K |
c = 9.0134 (6) Å | 0.41 × 0.21 × 0.09 mm |
β = 94.680 (1)° |
Bruker APEXII area-detector diffractometer | 3590 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 3363 reflections with I > 2σ(I) |
Tmin = 0.521, Tmax = 0.794 | Rint = 0.027 |
13303 measured reflections |
R[F2 > 2σ(F2)] = 0.026 | 0 restraints |
wR(F2) = 0.073 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.51 e Å−3 |
3590 reflections | Δρmin = −1.20 e Å−3 |
217 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 | ||
Cd1 | 0.14670 (3) | 0.059094 (11) | 0.42128 (3) | 0.01504 (7) | |
Cd2 | 0.68147 (3) | 0.061745 (12) | 0.92704 (3) | 0.01784 (8) | |
O1 | 0.2840 (3) | 0.05939 (15) | 0.6605 (3) | 0.0319 (6) | |
O1W | 0.1980 (5) | 0.17901 (19) | 0.9593 (4) | 0.0536 (9) | |
H1W | 0.1295 | 0.1483 | 0.9764 | 0.080* | |
H2W | 0.2732 | 0.1515 | 0.9428 | 0.080* | |
O2 | 0.4683 (3) | 0.11462 (15) | 0.8045 (3) | 0.0276 (6) | |
O3 | 0.3344 (3) | 0.02003 (13) | 0.2703 (3) | 0.0221 (5) | |
O4 | 0.4966 (4) | 0.05240 (15) | 0.1068 (3) | 0.0329 (6) | |
O5 | −0.0699 (3) | 0.05479 (12) | 0.5810 (3) | 0.0247 (5) | |
O6 | −0.1510 (4) | 0.11574 (15) | 0.7733 (3) | 0.0322 (6) | |
O7 | −0.0012 (3) | 0.08536 (15) | 0.1981 (3) | 0.0269 (6) | |
O8 | −0.2163 (3) | 0.14081 (13) | 0.1001 (3) | 0.0242 (5) | |
O9 | 0.8273 (3) | −0.01954 (14) | 1.0645 (3) | 0.0273 (6) | |
H9C | 0.9065 | 0.0038 | 1.1007 | 0.041* | |
H9D | 0.8001 | −0.0368 | 1.1453 | 0.041* | |
N1 | 0.3655 (3) | 0.14161 (14) | 0.4254 (3) | 0.0155 (5) | |
N2 | 0.0256 (3) | 0.17076 (14) | 0.4436 (3) | 0.0165 (5) | |
C1 | 0.3067 (4) | 0.21129 (17) | 0.4640 (4) | 0.0188 (6) | |
H1A | 0.3757 | 0.2465 | 0.4272 | 0.023* | |
H1B | 0.3108 | 0.2157 | 0.5714 | 0.023* | |
C2 | 0.1381 (4) | 0.22411 (18) | 0.3989 (4) | 0.0199 (6) | |
H2A | 0.1037 | 0.2694 | 0.4310 | 0.024* | |
H2B | 0.1364 | 0.2249 | 0.2911 | 0.024* | |
C3 | 0.4865 (4) | 0.1179 (2) | 0.5407 (4) | 0.0216 (7) | |
H3A | 0.5607 | 0.1554 | 0.5661 | 0.026* | |
H3B | 0.5451 | 0.0793 | 0.5031 | 0.026* | |
C4 | 0.4074 (4) | 0.09524 (19) | 0.6796 (4) | 0.0220 (7) | |
C5 | 0.4234 (4) | 0.13902 (17) | 0.2772 (4) | 0.0187 (6) | |
H5A | 0.5309 | 0.1568 | 0.2823 | 0.022* | |
H5B | 0.3580 | 0.1688 | 0.2106 | 0.022* | |
C6 | 0.4213 (4) | 0.06559 (17) | 0.2143 (4) | 0.0184 (6) | |
C7 | −0.0146 (4) | 0.17706 (17) | 0.5982 (4) | 0.0188 (6) | |
H7A | −0.0905 | 0.2145 | 0.6050 | 0.023* | |
H7B | 0.0801 | 0.1891 | 0.6608 | 0.023* | |
C8 | −0.0848 (4) | 0.10982 (17) | 0.6562 (4) | 0.0174 (6) | |
C9 | −0.1197 (4) | 0.17249 (19) | 0.3425 (4) | 0.0210 (7) | |
H9B | −0.1428 | 0.2204 | 0.3149 | 0.025* | |
H9A | −0.2071 | 0.1553 | 0.3953 | 0.025* | |
C10 | −0.1098 (4) | 0.12981 (18) | 0.2014 (4) | 0.0186 (6) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cd1 | 0.01578 (12) | 0.01422 (12) | 0.01525 (13) | −0.00099 (8) | 0.00208 (8) | −0.00100 (8) |
Cd2 | 0.02047 (13) | 0.02023 (13) | 0.01275 (13) | −0.00042 (8) | 0.00100 (8) | −0.00217 (8) |
O1 | 0.0324 (15) | 0.0417 (17) | 0.0206 (13) | −0.0122 (12) | −0.0048 (11) | 0.0092 (11) |
O1W | 0.070 (3) | 0.0403 (19) | 0.050 (2) | −0.0054 (17) | 0.0025 (18) | −0.0011 (16) |
O2 | 0.0296 (13) | 0.0371 (15) | 0.0150 (12) | 0.0079 (11) | −0.0056 (10) | −0.0027 (11) |
O3 | 0.0238 (12) | 0.0189 (12) | 0.0247 (13) | −0.0030 (9) | 0.0075 (10) | −0.0044 (10) |
O4 | 0.0396 (16) | 0.0387 (16) | 0.0227 (14) | −0.0024 (13) | 0.0155 (12) | −0.0081 (12) |
O5 | 0.0299 (13) | 0.0170 (12) | 0.0290 (14) | −0.0039 (10) | 0.0123 (11) | −0.0035 (10) |
O6 | 0.0424 (16) | 0.0318 (15) | 0.0247 (14) | −0.0105 (12) | 0.0170 (12) | −0.0059 (11) |
O7 | 0.0255 (13) | 0.0324 (14) | 0.0217 (13) | 0.0110 (11) | −0.0053 (10) | −0.0099 (11) |
O8 | 0.0294 (13) | 0.0231 (12) | 0.0185 (12) | −0.0001 (10) | −0.0071 (10) | −0.0010 (10) |
O9 | 0.0309 (14) | 0.0273 (14) | 0.0236 (14) | 0.0009 (11) | 0.0017 (11) | 0.0014 (10) |
N1 | 0.0163 (12) | 0.0173 (13) | 0.0130 (13) | −0.0013 (10) | 0.0009 (9) | −0.0007 (10) |
N2 | 0.0179 (12) | 0.0171 (13) | 0.0142 (13) | −0.0006 (10) | 0.0001 (10) | −0.0010 (10) |
C1 | 0.0194 (15) | 0.0157 (14) | 0.0218 (16) | −0.0049 (12) | 0.0042 (12) | −0.0038 (12) |
C2 | 0.0229 (16) | 0.0169 (15) | 0.0201 (16) | 0.0000 (12) | 0.0036 (12) | 0.0024 (12) |
C3 | 0.0174 (15) | 0.0294 (18) | 0.0175 (16) | −0.0021 (13) | −0.0006 (12) | −0.0002 (13) |
C4 | 0.0226 (16) | 0.0244 (17) | 0.0185 (17) | 0.0025 (13) | −0.0019 (13) | 0.0020 (13) |
C5 | 0.0228 (15) | 0.0179 (15) | 0.0157 (15) | −0.0032 (12) | 0.0043 (12) | −0.0006 (12) |
C6 | 0.0209 (15) | 0.0215 (16) | 0.0129 (14) | 0.0010 (12) | 0.0024 (11) | −0.0021 (12) |
C7 | 0.0260 (16) | 0.0149 (14) | 0.0159 (15) | −0.0007 (12) | 0.0036 (12) | −0.0037 (12) |
C8 | 0.0174 (14) | 0.0198 (15) | 0.0150 (15) | −0.0023 (12) | 0.0016 (11) | −0.0003 (12) |
C9 | 0.0195 (15) | 0.0255 (17) | 0.0178 (16) | 0.0045 (13) | −0.0009 (12) | −0.0045 (13) |
C10 | 0.0210 (15) | 0.0201 (15) | 0.0144 (15) | −0.0035 (12) | −0.0001 (11) | 0.0008 (12) |
Cd1—O5i | 2.284 (2) | O8—C10 | 1.248 (4) |
Cd1—O3 | 2.300 (2) | O8—Cd2viii | 2.297 (2) |
Cd1—O7 | 2.336 (3) | O9—H9C | 0.8500 |
Cd1—O1 | 2.365 (3) | O9—H9D | 0.8500 |
Cd1—N2 | 2.395 (3) | N1—C5 | 1.461 (4) |
Cd1—O5 | 2.423 (3) | N1—C3 | 1.471 (4) |
Cd1—N1 | 2.437 (3) | N1—C1 | 1.481 (4) |
Cd2—O2 | 2.277 (3) | N2—C7 | 1.466 (4) |
Cd2—O9 | 2.292 (3) | N2—C9 | 1.469 (4) |
Cd2—O8ii | 2.297 (2) | N2—C2 | 1.478 (4) |
Cd2—O6iii | 2.309 (3) | C1—C2 | 1.518 (5) |
Cd2—O4iv | 2.349 (3) | C1—H1A | 0.9700 |
Cd2—O3v | 2.370 (2) | C1—H1B | 0.9700 |
Cd2—O4v | 2.667 (3) | C2—H2A | 0.9700 |
O1—C4 | 1.252 (4) | C2—H2B | 0.9700 |
O1W—H1W | 0.8501 | C3—C4 | 1.531 (5) |
O1W—H2W | 0.8500 | C3—H3A | 0.9700 |
O2—C4 | 1.256 (4) | C3—H3B | 0.9700 |
O3—C6 | 1.275 (4) | C5—C6 | 1.522 (5) |
O3—Cd2v | 2.370 (2) | C5—H5A | 0.9700 |
O4—C6 | 1.229 (4) | C5—H5B | 0.9700 |
O4—Cd2vi | 2.349 (3) | C7—C8 | 1.533 (4) |
O5—C8 | 1.269 (4) | C7—H7A | 0.9700 |
O5—Cd1i | 2.284 (2) | C7—H7B | 0.9700 |
O6—C8 | 1.240 (4) | C9—C10 | 1.522 (5) |
O6—Cd2vii | 2.309 (3) | C9—H9B | 0.9700 |
O7—C10 | 1.257 (4) | C9—H9A | 0.9700 |
O5i—Cd1—O3 | 83.75 (9) | C3—N1—Cd1 | 107.09 (19) |
O5i—Cd1—O7 | 93.88 (10) | C1—N1—Cd1 | 108.87 (18) |
O3—Cd1—O7 | 84.76 (9) | C7—N2—C9 | 109.9 (3) |
O5i—Cd1—O1 | 97.39 (10) | C7—N2—C2 | 114.0 (3) |
O3—Cd1—O1 | 103.21 (10) | C9—N2—C2 | 109.9 (3) |
O7—Cd1—O1 | 166.82 (10) | C7—N2—Cd1 | 106.73 (19) |
O5i—Cd1—N2 | 137.48 (9) | C9—N2—Cd1 | 108.09 (19) |
O3—Cd1—N2 | 131.56 (9) | C2—N2—Cd1 | 108.04 (19) |
O7—Cd1—N2 | 71.06 (9) | N1—C1—C2 | 112.3 (3) |
O1—Cd1—N2 | 95.93 (10) | N1—C1—H1A | 109.1 |
O5i—Cd1—O5 | 75.17 (10) | C2—C1—H1A | 109.1 |
O3—Cd1—O5 | 158.86 (8) | N1—C1—H1B | 109.1 |
O7—Cd1—O5 | 98.08 (10) | C2—C1—H1B | 109.1 |
O1—Cd1—O5 | 78.34 (10) | H1A—C1—H1B | 107.9 |
N2—Cd1—O5 | 68.34 (9) | N2—C2—C1 | 112.8 (3) |
O5i—Cd1—N1 | 147.13 (9) | N2—C2—H2A | 109.0 |
O3—Cd1—N1 | 70.20 (9) | C1—C2—H2A | 109.0 |
O7—Cd1—N1 | 103.02 (10) | N2—C2—H2B | 109.0 |
O1—Cd1—N1 | 70.62 (9) | C1—C2—H2B | 109.0 |
N2—Cd1—N1 | 75.21 (9) | H2A—C2—H2B | 107.8 |
O5—Cd1—N1 | 128.62 (9) | N1—C3—C4 | 109.9 (3) |
O2—Cd2—O9 | 159.61 (10) | N1—C3—H3A | 109.7 |
O2—Cd2—O8ii | 105.87 (9) | C4—C3—H3A | 109.7 |
O9—Cd2—O8ii | 85.88 (10) | N1—C3—H3B | 109.7 |
O2—Cd2—O6iii | 90.53 (11) | C4—C3—H3B | 109.7 |
O9—Cd2—O6iii | 107.53 (11) | H3A—C3—H3B | 108.2 |
O8ii—Cd2—O6iii | 83.94 (10) | O1—C4—O2 | 124.2 (3) |
O2—Cd2—O4iv | 79.78 (11) | O1—C4—C3 | 117.4 (3) |
O9—Cd2—O4iv | 86.25 (10) | O2—C4—C3 | 118.3 (3) |
O8ii—Cd2—O4iv | 79.47 (10) | N1—C5—C6 | 112.2 (3) |
O6iii—Cd2—O4iv | 157.61 (10) | N1—C5—H5A | 109.2 |
O2—Cd2—O3v | 86.47 (9) | C6—C5—H5A | 109.2 |
O9—Cd2—O3v | 87.02 (9) | N1—C5—H5B | 109.2 |
O8ii—Cd2—O3v | 160.80 (9) | C6—C5—H5B | 109.2 |
O6iii—Cd2—O3v | 81.24 (9) | H5A—C5—H5B | 107.9 |
O4iv—Cd2—O3v | 117.83 (9) | O4—C6—O3 | 121.6 (3) |
C4—O1—Cd1 | 118.0 (2) | O4—C6—C5 | 119.6 (3) |
H1W—O1W—H2W | 97.5 | O3—C6—C5 | 118.7 (3) |
C4—O2—Cd2 | 123.6 (2) | N2—C7—C8 | 112.4 (3) |
C6—O3—Cd1 | 117.3 (2) | N2—C7—H7A | 109.1 |
C6—O3—Cd2v | 99.1 (2) | C8—C7—H7A | 109.1 |
Cd1—O3—Cd2v | 131.40 (11) | N2—C7—H7B | 109.1 |
C6—O4—Cd2vi | 161.0 (3) | C8—C7—H7B | 109.1 |
C8—O5—Cd1i | 139.8 (2) | H7A—C7—H7B | 107.9 |
C8—O5—Cd1 | 113.7 (2) | O6—C8—O5 | 127.1 (3) |
Cd1i—O5—Cd1 | 104.83 (10) | O6—C8—C7 | 115.3 (3) |
C8—O6—Cd2vii | 144.3 (2) | O5—C8—C7 | 117.6 (3) |
C10—O7—Cd1 | 117.9 (2) | N2—C9—C10 | 113.9 (3) |
C10—O8—Cd2viii | 126.5 (2) | N2—C9—H9B | 108.8 |
Cd2—O9—H9C | 102.7 | C10—C9—H9B | 108.8 |
Cd2—O9—H9D | 124.0 | N2—C9—H9A | 108.8 |
H9C—O9—H9D | 98.0 | C10—C9—H9A | 108.8 |
C5—N1—C3 | 111.7 (3) | H9B—C9—H9A | 107.7 |
C5—N1—C1 | 112.9 (3) | O8—C10—O7 | 125.7 (3) |
C3—N1—C1 | 110.0 (3) | O8—C10—C9 | 115.7 (3) |
C5—N1—Cd1 | 105.98 (19) | O7—C10—C9 | 118.5 (3) |
Symmetry codes: (i) −x, −y, −z+1; (ii) x+1, y, z+1; (iii) x+1, y, z; (iv) x, y, z+1; (v) −x+1, −y, −z+1; (vi) x, y, z−1; (vii) x−1, y, z; (viii) x−1, y, z−1. |
D—H···A | D—H | H···A | D···A | D—H···A |
O9—H9C···O7ii | 0.85 | 1.93 | 2.710 (4) | 151 |
O9—H9D···O1ix | 0.85 | 1.99 | 2.828 (4) | 168 |
O1W—H1W···O9ix | 0.85 | 2.53 | 3.081 (5) | 122 |
O1W—H2W···O2 | 0.85 | 2.26 | 3.038 (5) | 151 |
C5—H5B···O1Wvi | 0.97 | 2.55 | 3.399 (5) | 146 |
Symmetry codes: (ii) x+1, y, z+1; (vi) x, y, z−1; (ix) −x+1, −y, −z+2. |
Experimental details
Crystal data | |
Chemical formula | [Cd2(C10H12N2O8)(H2O)]·H2O |
Mr | 549.07 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 296 |
a, b, c (Å) | 8.4640 (6), 19.2334 (14), 9.0134 (6) |
β (°) | 94.680 (1) |
V (Å3) | 1462.41 (18) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.97 |
Crystal size (mm) | 0.41 × 0.21 × 0.09 |
Data collection | |
Diffractometer | Bruker APEXII area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.521, 0.794 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 13303, 3590, 3363 |
Rint | 0.027 |
(sin θ/λ)max (Å−1) | 0.665 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.026, 0.073, 1.03 |
No. of reflections | 3590 |
No. of parameters | 217 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.51, −1.20 |
Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL97 (Sheldrick, 2008) and DIAMOND (Brandenburg, 2005), SHELXTL97 (Sheldrick, 2008).
Cd1—O5i | 2.284 (2) | Cd2—O2 | 2.277 (3) |
Cd1—O3 | 2.300 (2) | Cd2—O9 | 2.292 (3) |
Cd1—O7 | 2.336 (3) | Cd2—O8ii | 2.297 (2) |
Cd1—O1 | 2.365 (3) | Cd2—O6iii | 2.309 (3) |
Cd1—N2 | 2.395 (3) | Cd2—O4iv | 2.349 (3) |
Cd1—O5 | 2.423 (3) | Cd2—O3v | 2.370 (2) |
Cd1—N1 | 2.437 (3) | ||
O5i—Cd1—O3 | 83.75 (9) | N2—Cd1—N1 | 75.21 (9) |
O5i—Cd1—O7 | 93.88 (10) | O2—Cd2—O8ii | 105.87 (9) |
O3—Cd1—O7 | 84.76 (9) | O9—Cd2—O8ii | 85.88 (10) |
O5i—Cd1—O1 | 97.39 (10) | O2—Cd2—O6iii | 90.53 (11) |
O3—Cd1—O1 | 103.21 (10) | O9—Cd2—O6iii | 107.53 (11) |
O7—Cd1—O1 | 166.82 (10) | O8ii—Cd2—O6iii | 83.94 (10) |
O7—Cd1—N2 | 71.06 (9) | O2—Cd2—O4iv | 79.78 (11) |
O1—Cd1—N2 | 95.93 (10) | O9—Cd2—O4iv | 86.25 (10) |
O5i—Cd1—O5 | 75.17 (10) | O8ii—Cd2—O4iv | 79.47 (10) |
O7—Cd1—O5 | 98.08 (10) | O2—Cd2—O3v | 86.47 (9) |
O1—Cd1—O5 | 78.34 (10) | O9—Cd2—O3v | 87.02 (9) |
N2—Cd1—O5 | 68.34 (9) | O8ii—Cd2—O3v | 160.80 (9) |
O3—Cd1—N1 | 70.20 (9) | O6iii—Cd2—O3v | 81.24 (9) |
O7—Cd1—N1 | 103.02 (10) | O4iv—Cd2—O3v | 117.83 (9) |
O1—Cd1—N1 | 70.62 (9) |
Symmetry codes: (i) −x, −y, −z+1; (ii) x+1, y, z+1; (iii) x+1, y, z; (iv) x, y, z+1; (v) −x+1, −y, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
O9—H9C···O7ii | 0.85 | 1.93 | 2.710 (4) | 151 |
O9—H9D···O1vi | 0.85 | 1.99 | 2.828 (4) | 168 |
O1W—H1W···O9vi | 0.85 | 2.53 | 3.081 (5) | 122 |
O1W—H2W···O2 | 0.85 | 2.26 | 3.038 (5) | 151 |
C5—H5B···O1Wvii | 0.97 | 2.55 | 3.399 (5) | 146 |
Symmetry codes: (ii) x+1, y, z+1; (vi) −x+1, −y, −z+2; (vii) x, y, z−1. |
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The construction of coordination polymers from multifunctional ligands with metal ions is one of the most active areas of materials research. The intense interest in these materials is driven by their intrinsic architectural beauty and aesthetically pleasing structures, as well as potential applications such as catalysis, molecular magnets, photoluminescence, adsorption and phase separation (Janiak, 2003; Kitagawa et al., 2004; O'Keeffe et al., 2000). The assembly of these coordination compounds allows for a wide choice of various parameters including diverse electronic properties and coordination geometries of the metal ions as well as versatile functions of organic ligands. To date, metal carboxylate frameworks have afforded the most diversity in this area because of their chemical stability and appropriate connectivity (Yaghi et al., 1997; Chen et al., 2009). Ethylenediaminetetraacetic acid (H4edta), which has ten potential donor atoms (eight O atoms and two N atoms), is an effective ligand for coordinating to metal cations to generate diverse structural networks (Luo & Xu, 2006; Mizuta et al., 1995). H4edta commonly acts as a chelating ligand to enclose a central metal ion, leaving some remaining sites available for coordination. Thus some bimetalic compounds have been isolated successfully through this strategy (Brouca-Cabarrecq et al., 1996; Yi et al., 1998). In addition, some structurally defined peroxotitanate–edta coordination compounds can delineate certain cleavage reaction mechanisms (Zhou et al., 2007). Although many compounds containing the H4edta ligand have been reported, new coordination compounds with interesting structures based on the H4edta ligand continue to be synthesized owing to the coordination versatility of the H4edta ligand.
On the other hand, because of the relatively large ionic radius of the CdII cation, its coordination numbers typically range from 6 to 8, which suggests that cadmium compounds should form some interesting frameworks (Liu et al., 2006). The combination of the H4edta ligand with cadmium(II) ions produced several complexes such as the mononuclear [Cd(H2edta)(H2O)].H2O (Polyakova et al., 2001), trinuclear [Cd3(Hedta)2(H2O)6] .H2O (Solans et al., 1987) and the polymeric bimetallic network {[Na2Cd3(Hedta)2(H2O)6].2H2O}n (Wang et al., 2008). However, all reported CdII compounds bridged by H4edta ligands with polymeric structures are heterometallic compounds (Llyukhin & Davidovich, 1999; Solans et al., 1985). We report here the cadmium compound {[Cd2(edta)(H2O)].H2O}n, (I), which is the first two-dimensional layered framework compound based on the edta ligand and homometallic cadmium ion. In addition, the edta ligand displays a novel heptadentate coordination mode in the compound.
The asymmetric unit of (I) consists of two CdII cations, one edta tetraanion, one coordinated water molecule and one solvent water molecule. As depicted in Fig. 1, atom Cd1 is seven-coordinated by four carboxylate O and two N atoms from an edta ligand and one carboxylate O atom [O5i; symmetry code: (i) -x, -y, -z + 1] from the other edta ligand in a pentagonal–bipyramidal coordination environment with atoms O1 and O7 occupying the apical positions. Atom Cd2 is six-coordinated by three carboxylate O atoms from three edta ligands and one coordinated water molecule in a distorted square-planar geometry, and two carboxylate O atoms [O8ii and O3v; symmetry codes: (ii) x + 1, y, z + 1; (v) -x + 1, -y, -z + 1] from another two edta ligands in the apical positions. The [CdO6] octahedron is distorted, with the O—Cd—O bond angles ranging from 79.47 (10) to 160.80 (9)° (Table 1). There is one additional interaction [Cd2—O4v = 2.667 (3) Å], but this is outside the typical range of 2.10–2.45 Å for Cd—O coordination.
Each edta ligand employs its carboxylate groups and two N atoms to chelate and bridge seven CdII cations (Fig. 2). The two neighboring Cd1 atoms are bridged by a pair of carboxylate O atoms (O5 and O5i) to form a centrosymmetric [Cd2(edta)2]4- unit containing a Cd2O2 core, located in the inverse centrum, with a Cd···Cd separation of 3.7314 (5) Å. Each [Cd2(edta)2]4- unit is surrounded by eight Cd2 atoms (Fig. 2). The [Cd2(edta)2]4- units are linked by Cd2 atoms through Cd2v—O3, Cd2vii—O4 and Cd2viii—O6 bonds [symmetry codes: (vii) x, y, z - 1; (viii) x - 1, y, z] to form a one-dimensional chain (Fig. 3). The one-dimensional chains are further linked by Cd2 atoms through Cd2—O2 and Cd2ix—O8 bonds [symmetry code: (ix) x - 1, y, z - 1] to generate a two-dimensional layer in the ac plane (Fig. 3). Thus, the Cd2 sites serve to join neighbouring [Cd2(edta)2]4- units into a two-dimensional layered structure. There are hydrogen bonds between aqua ligands and carboxylate O atoms within the layer (Table 2). The two-dimensional layers are stacked along the b direction to give a crystal packing (Fig. 4). The solvent water molecules occupy the space between the layers and interact with the host layers through O—H···O and C—H···O interactions (Table 2).
Several homometallic compounds bridged by edta ligand with two-dimensional structures have been reported previously. However, the structure of (I) is quite different from those structures. For example, the {[Ca2(edta)(H2O)2].H2O}n compound has a similar dinuclear [Ca2(edta)2(H2O)2]4- unit, which is extended into a two-dimensional layer through Ca—O bonds (Barnett & Uchtman, 1979). However, in this compound, each [Ca2(edta)2(H2O)2]4- unit is only surrounded by six CaII ions, and the edta ligand exhibits a hexadentate coordination mode, different from (I). The edta ligand chelates an Sn2+ ion and bridges four Sn2+ ions to generate a two-dimensional framework where the basic structural unit is the mononuclear [Sn(edta)]2- (Van Remoortere et al., 1971). This indicates that the structures of the final products are strongly influenced by the nature of the metal ions.
To examine the thermal stability of the compound and the structural variation as a function of temperature, thermogravimetric analysis (TGA) was performed on a single-phase polycrystalline sample of (I) (Fig. S1 in the supplementary materials). TGA of (I) indicates that a weight loss of 6.4% occurs between 308 and 333 K, corresponding to the loss of the solvent water molecule and aqua ligand (expected 6.5%), with a distinct plateau in the curve. The second weight loss, in the temperature range 403–463 K, corresponds to the incomplete decomposition of the edta ligand. A sharp continual weight loss occurred at 508 K, which is attributed to further decomposition of the organic ligand.