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The Cd
II atom has distorted pentagonal bipyramidal coordination geometry in the coordination polymer [Cd(TDA)(Him)
2(H
2O)]
n [where TDA
2− is the thiophene-2,5-dicarboxylate dianion (C
6H
2O
4S
2−) and Him is imidazole (C
3H
4N
2)]. The cadmium ion is bound by four carboxylate O atoms from two independent TDA
2− groups, two N atoms from two different imidazole ligands, and one water molecule. The carboxylate groups bind in bidentate mode to the Cd center, forming a linear chain structure such that the closest Cd
Cd distance is 10.577 (6) Å. The polymeric chains are connected
via hydrogen bonds and π–π stacking interactions into a three-dimensional network.
Supporting information
CCDC reference: 296632
Key indicators
- Single-crystal X-ray study
- T = 295 K
- Mean (C-C) = 0.014 Å
- R factor = 0.041
- wR factor = 0.168
- Data-to-parameter ratio = 16.7
checkCIF/PLATON results
No syntax errors found
Alert level C
PLAT213_ALERT_2_C Atom O1 has ADP max/min Ratio ............. 3.50 prolat
PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for Cd1
PLAT342_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ... 14
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........ 2
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) . 1.11 Ratio
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
5 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
0 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
1 ALERT type 3 Indicator that the structure quality may be low
2 ALERT type 4 Improvement, methodology, query or suggestion
Cadmium dinitrate tetrahydrate (3.08 g, 10 mmol) was added to an aqueous solution of thiophene-2,5-dicarboxylic acid (1.72 g, 10 mmol). The pH was adjusted to 6 with 0.1 M sodium hydroxide. Imidazole (1.34 g, 20 mmol) was then added. The mixture was stirred for 1 h and then sealed in a 50 ml Teflon-lined stainless steel bomb and held at 383 K for 3 d. The bomb was cooled naturally to room temperature, and colorless prismatic crystals of (I) were obtained. Analysis calculated for C12H12N4O5SCd: C 33.00, H 2.77, N 12.83%; found: C 32.96, H 2.74, N 12.85%.
The H atoms attached to C atoms and imidazole N atoms were placed in calculated positions, with C—H = 0.93 Å, N—H = 0.86 Å and Uiso(H) = 1.2Ueq(C,N), and were refined with the riding-model approximation. Water H atoms were located in a difference Fourier map and refined with O—H and H···H distance restraints of 0.85 (1) and 1.39 (1) Å, respectively, and with Uiso(H) = 1.5Ueq(O). The largest residual peak is 1.08 Å from the Cd atom and the deepest is hole is ?? Å from ??.
Data collection: RAPID-AUTO (Rigaku Corporation, 1998); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.
catena-Poly[[aquadiimidazolecadmium(II)]-µ-thiophene-2,5-dicarboxylato]
top
Crystal data top
[Cd(C6H2O4S)(C3H4N2)2(H2O)] | Z = 2 |
Mr = 436.72 | F(000) = 432 |
Triclinic, P1 | Dx = 1.838 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.7486 (15) Å | Cell parameters from 7316 reflections |
b = 10.577 (2) Å | θ = 3.0–27.5° |
c = 10.947 (2) Å | µ = 1.55 mm−1 |
α = 103.71 (3)° | T = 295 K |
β = 101.57 (3)° | Prism, colorless |
γ = 108.43 (3)° | 0.36 × 0.24 × 0.18 mm |
V = 789.1 (4) Å3 | |
Data collection top
Rigaku R-AXIS RAPID diffractometer | 3564 independent reflections |
Radiation source: fine-focus sealed tube | 2125 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.086 |
Detector resolution: 10 pixels mm-1 | θmax = 27.5°, θmin = 3.0° |
ω scans | h = −9→10 |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | k = −13→13 |
Tmin = 0.641, Tmax = 0.761 | l = −14→11 |
7628 measured reflections | |
Refinement top
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)] = 0.041 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.168 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.06 | w = 1/[σ2(Fo2) + (0.0795P)2] where P = (Fo2 + 2Fc2)/3 |
3564 reflections | (Δ/σ)max < 0.001 |
214 parameters | Δρmax = 1.78 e Å−3 |
3 restraints | Δρmin = −1.65 e Å−3 |
Crystal data top
[Cd(C6H2O4S)(C3H4N2)2(H2O)] | γ = 108.43 (3)° |
Mr = 436.72 | V = 789.1 (4) Å3 |
Triclinic, P1 | Z = 2 |
a = 7.7486 (15) Å | Mo Kα radiation |
b = 10.577 (2) Å | µ = 1.55 mm−1 |
c = 10.947 (2) Å | T = 295 K |
α = 103.71 (3)° | 0.36 × 0.24 × 0.18 mm |
β = 101.57 (3)° | |
Data collection top
Rigaku R-AXIS RAPID diffractometer | 3564 independent reflections |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | 2125 reflections with I > 2σ(I) |
Tmin = 0.641, Tmax = 0.761 | Rint = 0.086 |
7628 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.041 | 3 restraints |
wR(F2) = 0.168 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.06 | Δρmax = 1.78 e Å−3 |
3564 reflections | Δρmin = −1.65 e Å−3 |
214 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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Cd1 | 0.21550 (8) | 0.13174 (6) | 0.24203 (6) | 0.0330 (2) | |
S1 | 0.1860 (3) | 0.6113 (2) | 0.2039 (2) | 0.0362 (5) | |
O1W | −0.1113 (9) | 0.0124 (6) | 0.1333 (6) | 0.0416 (14) | |
O1 | 0.2263 (11) | 0.2568 (7) | 0.0406 (10) | 0.083 (3) | |
O2 | 0.1526 (9) | 0.3269 (7) | 0.2207 (9) | 0.060 (2) | |
O3 | 0.2784 (9) | 0.9456 (6) | 0.0900 (6) | 0.0452 (15) | |
O4 | 0.1993 (9) | 0.9063 (7) | 0.2621 (7) | 0.0503 (16) | |
N1 | 0.1869 (10) | 0.1785 (9) | 0.4484 (8) | 0.0499 (19) | |
N2 | 0.0766 (13) | 0.1798 (8) | 0.6174 (8) | 0.051 (2) | |
N3 | 0.5332 (9) | 0.2600 (8) | 0.3021 (8) | 0.0432 (17) | |
N4 | 0.8273 (10) | 0.3311 (9) | 0.2983 (9) | 0.054 (2) | |
C1 | 0.1985 (12) | 0.3449 (10) | 0.1212 (14) | 0.060 (3) | |
C10 | 0.6629 (12) | 0.2187 (10) | 0.2620 (10) | 0.045 (2) | |
C11 | 0.6190 (15) | 0.4018 (11) | 0.3577 (11) | 0.064 (3) | |
C12 | 0.8015 (14) | 0.4472 (11) | 0.3620 (11) | 0.060 (3) | |
C2 | 0.2286 (11) | 0.4832 (9) | 0.0998 (9) | 0.040 (2) | |
C3 | 0.2954 (12) | 0.5263 (9) | 0.0019 (9) | 0.044 (2) | |
C4 | 0.3111 (12) | 0.6694 (8) | 0.0178 (8) | 0.0352 (18) | |
C5 | 0.2550 (10) | 0.7282 (8) | 0.1211 (7) | 0.0293 (16) | |
C6 | 0.2438 (11) | 0.8691 (8) | 0.1598 (8) | 0.0332 (17) | |
C7 | 0.0363 (13) | 0.1639 (10) | 0.4944 (10) | 0.048 (2) | |
C8 | 0.3338 (14) | 0.2176 (14) | 0.5630 (10) | 0.069 (3) | |
C9 | 0.2646 (16) | 0.2170 (13) | 0.6624 (10) | 0.063 (3) | |
H10 | 0.6433 | 0.1268 | 0.2162 | 0.053* | |
H11 | 0.5581 | 0.4599 | 0.3889 | 0.077* | |
H12 | 0.8920 | 0.5387 | 0.4004 | 0.072* | |
H14 | −0.0026 | 0.1686 | 0.6627 | 0.061* | |
H15 | 0.9317 | 0.3296 | 0.2835 | 0.065* | |
H1W1 | −0.142 (14) | 0.049 (8) | 0.075 (6) | 0.062* | |
H1W2 | −0.132 (14) | −0.073 (3) | 0.096 (7) | 0.062* | |
H3 | 0.3255 | 0.4714 | −0.0639 | 0.053* | |
H4 | 0.3555 | 0.7179 | −0.0374 | 0.042* | |
H7 | −0.0854 | 0.1441 | 0.4419 | 0.057* | |
H8 | 0.4618 | 0.2406 | 0.5683 | 0.082* | |
H9 | 0.3344 | 0.2389 | 0.7495 | 0.076* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cd1 | 0.0388 (3) | 0.0268 (3) | 0.0415 (4) | 0.0160 (2) | 0.0178 (2) | 0.0159 (2) |
S1 | 0.0380 (11) | 0.0313 (11) | 0.0513 (13) | 0.0172 (9) | 0.0196 (9) | 0.0236 (10) |
O1W | 0.047 (3) | 0.034 (3) | 0.041 (3) | 0.014 (3) | 0.011 (3) | 0.012 (3) |
O1 | 0.068 (5) | 0.021 (4) | 0.146 (8) | 0.025 (3) | 0.014 (5) | 0.007 (4) |
O2 | 0.050 (4) | 0.040 (4) | 0.116 (6) | 0.027 (3) | 0.036 (4) | 0.050 (4) |
O3 | 0.059 (4) | 0.028 (3) | 0.058 (4) | 0.021 (3) | 0.018 (3) | 0.023 (3) |
O4 | 0.066 (4) | 0.042 (4) | 0.061 (4) | 0.028 (3) | 0.035 (3) | 0.023 (3) |
N1 | 0.043 (4) | 0.061 (5) | 0.046 (4) | 0.012 (4) | 0.020 (3) | 0.025 (4) |
N2 | 0.082 (6) | 0.042 (5) | 0.046 (5) | 0.033 (4) | 0.041 (4) | 0.015 (4) |
N3 | 0.037 (4) | 0.034 (4) | 0.062 (5) | 0.015 (3) | 0.019 (3) | 0.017 (4) |
N4 | 0.032 (4) | 0.061 (6) | 0.080 (6) | 0.021 (4) | 0.018 (4) | 0.036 (5) |
C1 | 0.026 (4) | 0.026 (5) | 0.122 (10) | 0.013 (4) | 0.000 (5) | 0.027 (6) |
C2 | 0.026 (4) | 0.033 (5) | 0.056 (6) | 0.009 (3) | 0.004 (4) | 0.015 (4) |
C3 | 0.050 (5) | 0.036 (5) | 0.041 (5) | 0.019 (4) | 0.011 (4) | 0.000 (4) |
C4 | 0.053 (5) | 0.025 (4) | 0.034 (4) | 0.024 (4) | 0.016 (4) | 0.006 (3) |
C5 | 0.031 (4) | 0.023 (4) | 0.032 (4) | 0.010 (3) | 0.006 (3) | 0.010 (3) |
C6 | 0.032 (4) | 0.026 (4) | 0.037 (4) | 0.009 (3) | 0.006 (3) | 0.009 (4) |
C7 | 0.049 (5) | 0.036 (5) | 0.067 (7) | 0.023 (4) | 0.020 (5) | 0.021 (5) |
C8 | 0.040 (5) | 0.094 (9) | 0.039 (6) | −0.002 (5) | 0.004 (4) | 0.008 (6) |
C9 | 0.074 (7) | 0.067 (8) | 0.032 (5) | 0.020 (6) | 0.017 (5) | −0.004 (5) |
C10 | 0.042 (5) | 0.040 (5) | 0.064 (6) | 0.025 (4) | 0.018 (4) | 0.023 (5) |
C11 | 0.072 (7) | 0.043 (6) | 0.060 (7) | 0.010 (5) | 0.035 (5) | −0.011 (5) |
C12 | 0.051 (6) | 0.041 (6) | 0.072 (7) | 0.007 (5) | 0.014 (5) | 0.007 (5) |
Geometric parameters (Å, º) top
Cd1—O1W | 2.341 (6) | N2—H14 | 0.8600 |
Cd1—O1 | 2.829 (6) | N3—C10 | 1.326 (11) |
Cd1—O2 | 2.318 (6) | N3—C11 | 1.355 (12) |
Cd1—O3i | 2.503 (6) | N4—C10 | 1.346 (12) |
Cd1—O4i | 2.413 (6) | N4—C12 | 1.356 (13) |
Cd1—N1 | 2.267 (8) | N4—H15 | 0.8600 |
Cd1—N3 | 2.269 (7) | C1—C2 | 1.489 (12) |
O1—C1 | 1.227 (14) | C2—C3 | 1.390 (13) |
O2—C1 | 1.249 (14) | C3—C4 | 1.444 (12) |
O3—C6 | 1.244 (9) | C3—H3 | 0.9300 |
O4—C6 | 1.248 (10) | C4—C5 | 1.374 (11) |
S1—C2 | 1.716 (10) | C4—H4 | 0.9300 |
S1—C5 | 1.716 (7) | C5—C6 | 1.485 (11) |
O1W—H1W1 | 0.85 (7) | C7—H7 | 0.9300 |
O1W—H1W2 | 0.85 (6) | C8—C9 | 1.306 (14) |
O3—Cd1ii | 2.503 (6) | C8—H8 | 0.9300 |
O4—Cd1ii | 2.413 (6) | C9—H9 | 0.9300 |
N1—C7 | 1.340 (11) | C10—H10 | 0.9300 |
N1—C8 | 1.387 (12) | C11—C12 | 1.329 (14) |
N2—C7 | 1.277 (12) | C11—H11 | 0.9300 |
N2—C9 | 1.333 (13) | C12—H12 | 0.9300 |
| | | |
N3—Cd1—O1 | 80.4 (3) | N4—C12—H12 | 127.5 |
O1W—Cd1—O1 | 86.1 (3) | C1—C2—S1 | 120.7 (8) |
O2—Cd1—O1 | 49.1 (3) | C1—O2—Cd1 | 104.5 (6) |
O1—Cd1—O3i | 84.4 (3) | C2—C3—C4 | 109.7 (8) |
O1—Cd1—O4i | 136.0 (2) | C2—C3—H3 | 125.2 |
O1—CD1—N1 | 139.2 (2) | C2—S1—C5 | 92.8 (4) |
N1—Cd1—N3 | 96.3 (3) | C3—C2—C1 | 126.7 (9) |
N1—Cd1—O2 | 90.5 (3) | C3—C2—S1 | 112.6 (6) |
N3—Cd1—O2 | 90.2 (2) | C3—C4—H4 | 122.7 |
N1—Cd1—O1W | 95.8 (2) | C4—C3—H3 | 125.2 |
N3—Cd1—O1W | 166.2 (2) | C4—C5—C6 | 128.1 (7) |
O2—Cd1—O1W | 83.2 (2) | C4—C5—S1 | 110.4 (6) |
N1—Cd1—O4i | 84.6 (3) | C5—C4—C3 | 114.6 (8) |
N3—Cd1—O4i | 103.5 (2) | C5—C4—H4 | 122.7 |
O2—Cd1—O4i | 165.8 (2) | C6—C5—S1 | 121.4 (6) |
O1W—Cd1—O4i | 84.1 (2) | C6—O3—Cd1ii | 90.4 (5) |
N1—Cd1—O3i | 136.3 (2) | C6—O4—Cd1ii | 94.5 (5) |
N3—Cd1—O3i | 86.4 (2) | C7—N1—C8 | 101.7 (8) |
O2—Cd1—O3i | 133.2 (2) | C7—N1—Cd1 | 132.8 (7) |
O1W—Cd1—O3i | 89.3 (2) | C7—N2—C9 | 107.0 (8) |
O4i—Cd1—O3i | 52.7 (2) | C7—N2—H14 | 126.5 |
Cd1—O1W—H1W1 | 108 (7) | C8—C9—H9 | 125.9 |
Cd1—O1W—H1W2 | 108 (7) | C8—C9—N2 | 108.2 (9) |
O1—C1—C2 | 117.1 (12) | C8—N1—Cd1 | 125.1 (7) |
O1—C1—O2 | 124.2 (9) | C9—C8—H8 | 125.2 |
O2—C1—C2 | 118.7 (10) | C9—C8—N1 | 109.5 (9) |
O3—C6—C5 | 119.4 (8) | C9—N2—H14 | 126.5 |
O3—C6—O4 | 122.4 (8) | C10—N3—C11 | 105.6 (8) |
O4—C6—C5 | 118.3 (7) | C10—N3—Cd1 | 126.6 (7) |
N1—C7—H7 | 123.3 | C10—N4—C12 | 108.8 (8) |
N1—C8—H8 | 125.2 | C10—N4—H15 | 125.6 |
N2—C7—H7 | 123.3 | C11—C12—H12 | 127.5 |
N2—C7—N1 | 113.4 (9) | C11—C12—N4 | 105.1 (9) |
N2—C9—H9 | 125.9 | C11—N3—Cd1 | 125.9 (6) |
N3—C10—H10 | 125.5 | C12—C11—H11 | 124.4 |
N3—C10—N4 | 109.0 (9) | C12—C11—N3 | 111.2 (9) |
N3—C11—H11 | 124.4 | C12—N4—H15 | 125.6 |
N4—C10—H10 | 125.5 | H1W1—O1W—H1W2 | 109 (7) |
| | | |
C1—C2—C3—C4 | −177.8 (7) | N1—Cd1—O2—C1 | 166.5 (6) |
C10—N3—C11—C12 | −4.8 (13) | N3—C11—C12—N4 | 4.4 (14) |
C10—N4—C12—C11 | −2.3 (12) | N3—Cd1—N1—C7 | 164.2 (9) |
C11—N3—C10—N4 | 3.2 (11) | N3—Cd1—N1—C8 | −23.8 (9) |
C12—N4—C10—N3 | −0.6 (11) | N3—Cd1—O2—C1 | 70.2 (6) |
C2—C3—C4—C5 | −1.1 (10) | O1—C1—C2—C3 | −3.9 (13) |
C2—S1—C5—C4 | −0.8 (6) | O1—C1—C2—S1 | 177.9 (7) |
C2—S1—C5—C6 | 177.1 (6) | O1W—Cd1—N1—C7 | −9.2 (9) |
C3—C4—C5—C6 | −176.5 (7) | O1W—Cd1—N1—C8 | 162.7 (9) |
C3—C4—C5—S1 | 1.2 (9) | O1W—Cd1—N3—C10 | −76.2 (13) |
C4—C5—C6—O3 | 4.1 (12) | O1W—Cd1—N3—C11 | 86.0 (14) |
C4—C5—C6—O4 | −176.0 (8) | O1W—Cd1—O2—C1 | −97.7 (6) |
C5—S1—C2—C1 | 178.6 (6) | O2—C1—C2—C3 | 174.1 (8) |
C5—S1—C2—C3 | 0.1 (6) | O2—C1—C2—S1 | −4.2 (11) |
C7—N1—C8—C9 | 2.9 (13) | O2—Cd1—N1—C7 | 74.0 (9) |
C7—N2—C9—C8 | −2.4 (13) | O2—Cd1—N1—C8 | −114.1 (9) |
C8—N1—C7—N2 | −4.6 (12) | O2—Cd1—N3—C10 | −137.3 (8) |
C9—N2—C7—N1 | 4.6 (11) | O2—Cd1—N3—C11 | 24.9 (9) |
Cd1—N1—C7—N2 | 168.7 (7) | O3i—Cd1—N1—C7 | −104.3 (9) |
Cd1—N1—C8—C9 | −171.1 (8) | O3i—Cd1—N1—C8 | 67.6 (10) |
Cd1—N3—C10—N4 | 168.3 (6) | O3i—Cd1—N3—C10 | −4.0 (8) |
Cd1—N3—C11—C12 | −170.1 (8) | O3i—Cd1—N3—C11 | 158.2 (9) |
Cd1—O2—C1—C2 | −163.0 (6) | O3i—Cd1—O2—C1 | −15.1 (7) |
Cd1—O2—C1—O1 | 14.8 (11) | O4i—Cd1—N1—C7 | −92.7 (9) |
Cd1ii—O3—C6—C5 | 179.6 (6) | O4i—Cd1—N1—C8 | 79.2 (9) |
Cd1ii—O3—C6—O4 | −0.3 (8) | O4i—Cd1—N3—C10 | 46.2 (8) |
Cd1ii—O4—C6—C5 | −179.6 (6) | O4i—Cd1—N3—C11 | −151.6 (8) |
Cd1ii—O4—C6—O3 | 0.3 (8) | O4i—Cd1—O2—C1 | −123.9 (10) |
N1—C8—C9—N2 | −0.4 (14) | S1—C2—C3—C4 | 0.5 (9) |
N1—Cd1—N3—C10 | 132.2 (8) | S1—C5—C6—O3 | −173.4 (6) |
N1—Cd1—N3—C11 | −65.6 (9) | S1—C5—C6—O4 | 6.5 (10) |
Symmetry codes: (i) x, y−1, z; (ii) x, y+1, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1W1···O3iii | 0.85 (7) | 1.93 (4) | 2.732 (8) | 157 (8) |
O1W—H1W2···O1iv | 0.85 (6) | 1.96 (3) | 2.770 (10) | 160 (7) |
N2—H14···O4v | 0.86 | 1.92 | 2.758 (10) | 165 |
N4—H15···O2vi | 0.86 | 1.97 | 2.826 (10) | 171 |
Symmetry codes: (iii) −x, −y+1, −z; (iv) −x, −y, −z; (v) −x, −y+1, −z+1; (vi) x+1, y, z. |
Experimental details
Crystal data |
Chemical formula | [Cd(C6H2O4S)(C3H4N2)2(H2O)] |
Mr | 436.72 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 295 |
a, b, c (Å) | 7.7486 (15), 10.577 (2), 10.947 (2) |
α, β, γ (°) | 103.71 (3), 101.57 (3), 108.43 (3) |
V (Å3) | 789.1 (4) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 1.55 |
Crystal size (mm) | 0.36 × 0.24 × 0.18 |
|
Data collection |
Diffractometer | Rigaku R-AXIS RAPID diffractometer |
Absorption correction | Multi-scan (ABSCOR; Higashi, 1995) |
Tmin, Tmax | 0.641, 0.761 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 7628, 3564, 2125 |
Rint | 0.086 |
(sin θ/λ)max (Å−1) | 0.649 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.168, 1.06 |
No. of reflections | 3564 |
No. of parameters | 214 |
No. of restraints | 3 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 1.78, −1.65 |
Selected geometric parameters (Å, º) topCd1—O1W | 2.341 (6) | Cd1—N3 | 2.269 (7) |
Cd1—O1 | 2.829 (6) | O1—C1 | 1.227 (14) |
Cd1—O2 | 2.318 (6) | O2—C1 | 1.249 (14) |
Cd1—O3i | 2.503 (6) | O3—C6 | 1.244 (9) |
Cd1—O4i | 2.413 (6) | O4—C6 | 1.248 (10) |
Cd1—N1 | 2.267 (8) | | |
| | | |
N3—Cd1—O1 | 80.4 (3) | O2—Cd1—O1W | 83.2 (2) |
O1W—Cd1—O1 | 86.1 (3) | N1—Cd1—O4i | 84.6 (3) |
O2—Cd1—O1 | 49.1 (3) | N3—Cd1—O4i | 103.5 (2) |
O1—Cd1—O3i | 84.4 (3) | O2—Cd1—O4i | 165.8 (2) |
O1—Cd1—O4i | 136.0 (2) | O1W—Cd1—O4i | 84.1 (2) |
O1—CD1—N1 | 139.2 (2) | N1—Cd1—O3i | 136.3 (2) |
N1—Cd1—N3 | 96.3 (3) | N3—Cd1—O3i | 86.4 (2) |
N1—Cd1—O2 | 90.5 (3) | O2—Cd1—O3i | 133.2 (2) |
N3—Cd1—O2 | 90.2 (2) | O1W—Cd1—O3i | 89.3 (2) |
N1—Cd1—O1W | 95.8 (2) | O4i—Cd1—O3i | 52.7 (2) |
N3—Cd1—O1W | 166.2 (2) | | |
Symmetry code: (i) x, y−1, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1W1···O3ii | 0.85 (7) | 1.93 (4) | 2.732 (8) | 157 (8) |
O1W—H1W2···O1iii | 0.85 (6) | 1.96 (3) | 2.770 (10) | 160 (7) |
N2—H14···O4iv | 0.86 | 1.92 | 2.758 (10) | 165 |
N4—H15···O2v | 0.86 | 1.97 | 2.826 (10) | 171 |
Symmetry codes: (ii) −x, −y+1, −z; (iii) −x, −y, −z; (iv) −x, −y+1, −z+1; (v) x+1, y, z. |
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Thiophene-2,5-dicarboxylic acid (H2TDA) is reported to be a potential anticancer agent (Sahasrabudhe et al., 1960), and additionally an excellent building block for constructing coordination polymers (Chen et al., 1993). In previously studied polymers of this type, the versatile H2TDA ligand shows a variety of binding modes to metal ions, from mono- to tetradentate (Chen et al., 1998, 1999). In order to further the study of H2TDA coordination modes, we report here the synthesis and crystal structure of the title CdII coordination polymer, [Cd(TDA)(Him)2(H2O)]n, (I). It was obtained by the hydrothermal reaction of cadmium dinitrate tetrahydrate, thiophene-2,5-dicarboxylic acid and imidazole (Him) in an aqueous solution.
As illustrated in Fig. 1, the asymmetric unit of (I) consists of one CdII ion, one TDA2− dianion, two imidazole ligands and one coordinated water molecule. Each CdII atom is seven-coordinate and bound by four carboxyl O atoms from two independent TDA2− groups, two N atoms from two different imidazole ligands, and one water molecule. The local coordination sphere of the CdII atom can be described as distorted pentagonal bipyramidal. The equatorial pentagonal plane is defined by atoms O1, O2, O3i, O4i and N1 [symmetry code: (i) x, y − 1, z]. Atom N3 and the water molecule occupy the axial sites. The smallest O—Cd—O angle, 49.1 (3)°, is attributed to the bis-chelate coordination of the TDA2− ligand that forms two four-membered rings. It should be noted that the two C—O bond distances of the carboxyl group (O3/C6/O4) are almost equivalent, and so in agreement with its delocalized state, whereas the O2—C1 distance is longer than the O1—C1 distance, in accordance with the formal double-bond character of the O1—C1 bond. The dihedral angles between the two carboxyl groups and the thiophene ring are 5.3 (4)° (O1/C1/O2) and 6.0 (4)° (O3/C6/O4), respectively, demonstrating that the TDA2− ligand is basically planar.
Each TDA2− group binds in bis-bidentate chelating mode to link neighbouring CdII atoms to form a one-dimensional linear chain structure which is propagated parallel to the b axis (Fig. 2), in which the closest Cd···Cd distance is 10.577 (6) Å. Furthermore, the water and imidazole molecules form extensive intermolecular hydrogen bonds with carboxylate O atoms (Table 2). There are π–π stacking interactions between adjacent thiophene rings, the centroid–centroid separation being 3.694 (6) Å. The polymeric chains align in a manner that facilitates both hydrogen-bonding and π–π stacking interactions, leading to a three-dimensional supramolecular network (Fig. 3).