Acta Cryst. (2008). E64, m185 [ doi:10.1107/S1600536807066147 ]
![[mu]](/logos/entities/mu_rmgif.gif)
2-oxalato]The title compound, [Cd(C2O4)(C3H7NO)2]n, is isostructural with its MnII analogue. The structure comprises zigzag polymeric chains with the oxalate groups situated on inversion centres and the CdII atoms located on twofold rotation axes. The coordination geometry around CdII is distorted octahedral and the intrachain Cd
Cd distance is 5.842 (1) Å. C-HO hydrogen bonds exist between the parallel polymeric chains.
All chemicals used in the first step of the synthesis were purchased from Aldrich and used without further purification. 1.81 g (2 mmol) oxalic acid was dissolved in 15 ml H2O. 0.42 g (1 mmol) LiOH.H2O and 0.62 g (1 mmol) H3BO3 were dissolved in 15 ml H2O and added to the solution.The mixture was brought to boiling and evaporated to dryness. The resulting Li[B(ox)2] was dried in a desiccator (Zavalij et al., 2003). A solution of 3.9 g Li[B(ox)2] in 50 ml DMF was prepared and heated to 343 K. A precipitate formed, probably a sign of the disintegration of the bis(oxalate)borate ion, and the solution was filtered. One eighth of this filtrate was then mixed with a solution of 0.2 g C d(NO3)2.4H2O and the resulting solution was set aside for 1–2 weeks, after which colourless prismatic crystals suitable for x-ray diffraction were collected and dried.
H atoms were placed in idealized positions and refined using a riding model with Uiso(H) = 1.2 Ueq(C).
Data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXTL (Bruker, 2003); program(s) used to refine structure: SHELXTL (Bruker, 2003); molecular graphics: DIAMOND (Brandenburg, 2007); software used to prepare material for publication: SHELXTL (Bruker, 2003).
![[Figure 1]](./bi2270fig1thm.gif)
| Fig. 1. Perspective drawing showing the atom-numbering scheme and atomic displacement ellipsoids at the 50% probability level for non-H atoms. Symmetry codes: (i) -x + 1, y, -z + 1/2; (ii) -x + 1, -y, -z. |
![[Figure 2]](./bi2270fig2thm.gif)
| Fig. 2. A projection in the bc-plane showing the one-dimensional chain propagating along the c-direction. |
| [Cd(C2O4)(C3H7NO)2] | F000 = 688 |
| Mr = 346.61 | Dx = 1.824 Mg m−3 |
| Orthorhombic, Pbcn | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: -P 2n 2ab | Cell parameters from 2301 reflections |
| a = 15.153 (4) Å | θ = 2.7–32.9º |
| b = 8.006 (2) Å | µ = 1.75 mm−1 |
| c = 10.403 (3) Å | T = 153 (2) K |
| V = 1262.0 (6) Å3 | Prism, colourless |
| Z = 4 | 0.41 × 0.31 × 0.19 mm |
| Siemens SMART CCD diffractometer | 2301 independent reflections |
| Radiation source: fine-focus sealed tube | 1705 reflections with I > 2σ(I) |
| Monochromator: graphite | Rint = 0.055 |
| T = 153(2) K | θmax = 32.9º |
| ω scans | θmin = 2.7º |
| Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | h = −23→23 |
| Tmin = 0.523, Tmax = 0.718 | k = −12→12 |
| 19498 measured reflections | l = −15→15 |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.025 | H-atom parameters constrained |
| wR(F2) = 0.077 | w = 1/[σ2(Fo2) + (0.0446P)2 + 0.4422P] where P = (Fo2 + 2Fc2)/3 |
| S = 1.01 | (Δ/σ)max < 0.001 |
| 2301 reflections | Δρmax = 1.28 e Å−3 |
| 80 parameters | Δρmin = −0.75 e Å−3 |
| Primary atom site location: structure-invariant direct methods | Extinction correction: none |
| [Cd(C2O4)(C3H7NO)2] | V = 1262.0 (6) Å3 |
| Mr = 346.61 | Z = 4 |
| Orthorhombic, Pbcn | Mo Kα |
| a = 15.153 (4) Å | µ = 1.75 mm−1 |
| b = 8.006 (2) Å | T = 153 (2) K |
| c = 10.403 (3) Å | 0.41 × 0.31 × 0.19 mm |
| Siemens SMART CCD diffractometer | 2301 independent reflections |
| Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | 1705 reflections with I > 2σ(I) |
| Tmin = 0.523, Tmax = 0.718 | Rint = 0.055 |
| 19498 measured reflections |
| R[F2 > 2σ(F2)] = 0.025 | 80 parameters |
| wR(F2) = 0.077 | H-atom parameters constrained |
| S = 1.01 | Δρmax = 1.28 e Å−3 |
| 2301 reflections | Δρmin = −0.75 e Å−3 |
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 | 0.5000 | 0.16606 (2) | 0.2500 | 0.01965 (7) | |
| O2 | 0.42585 (9) | 0.14921 (17) | 0.06167 (13) | 0.0290 (3) | |
| O1 | 0.57439 (8) | −0.02193 (18) | 0.12849 (12) | 0.0285 (3) | |
| O3 | 0.40504 (9) | 0.37996 (18) | 0.30029 (13) | 0.0278 (3) | |
| N1 | 0.33333 (10) | 0.6091 (2) | 0.22806 (14) | 0.0234 (3) | |
| C3 | 0.38865 (12) | 0.4853 (2) | 0.21484 (18) | 0.0247 (3) | |
| H3 | 0.4185 | 0.4745 | 0.1349 | 0.030* | |
| C1 | 0.45726 (11) | 0.0493 (2) | −0.01929 (16) | 0.0212 (3) | |
| C5 | 0.31781 (15) | 0.7309 (3) | 0.1264 (2) | 0.0377 (5) | |
| H5A | 0.3549 | 0.7041 | 0.0521 | 0.057* | |
| H5B | 0.3325 | 0.8429 | 0.1579 | 0.057* | |
| H5C | 0.2556 | 0.7277 | 0.1010 | 0.057* | |
| C4 | 0.28609 (13) | 0.6360 (3) | 0.34853 (19) | 0.0291 (4) | |
| H4A | 0.2970 | 0.5418 | 0.4066 | 0.044* | |
| H4B | 0.2227 | 0.6445 | 0.3312 | 0.044* | |
| H4C | 0.3068 | 0.7395 | 0.3887 | 0.044* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Cd1 | 0.02016 (11) | 0.02378 (11) | 0.01502 (10) | 0.000 | −0.00112 (5) | 0.000 |
| O2 | 0.0281 (6) | 0.0385 (7) | 0.0203 (6) | 0.0124 (5) | −0.0054 (5) | −0.0067 (5) |
| O1 | 0.0272 (6) | 0.0388 (8) | 0.0194 (5) | 0.0088 (5) | −0.0083 (4) | −0.0069 (5) |
| O3 | 0.0297 (7) | 0.0312 (7) | 0.0224 (6) | 0.0071 (6) | 0.0048 (5) | 0.0032 (6) |
| N1 | 0.0242 (7) | 0.0274 (8) | 0.0187 (6) | 0.0024 (6) | −0.0015 (5) | −0.0004 (6) |
| C3 | 0.0259 (8) | 0.0293 (9) | 0.0189 (7) | 0.0019 (7) | 0.0027 (6) | −0.0014 (7) |
| C1 | 0.0197 (8) | 0.0251 (7) | 0.0186 (7) | 0.0027 (6) | −0.0025 (5) | −0.0002 (6) |
| C5 | 0.0463 (12) | 0.0414 (12) | 0.0254 (9) | 0.0106 (10) | −0.0008 (8) | 0.0063 (9) |
| C4 | 0.0246 (9) | 0.0371 (10) | 0.0257 (9) | 0.0038 (7) | 0.0044 (7) | −0.0024 (8) |
| Cd1—O2i | 2.2624 (14) | N1—C4 | 1.459 (2) |
| Cd1—O2 | 2.2624 (14) | C3—H3 | 0.9500 |
| Cd1—O1i | 2.2658 (13) | C1—O1ii | 1.2524 (19) |
| Cd1—O1 | 2.2658 (13) | C1—C1ii | 1.569 (3) |
| Cd1—O3 | 2.2971 (14) | C5—H5A | 0.9800 |
| Cd1—O3i | 2.2972 (14) | C5—H5B | 0.9800 |
| O2—C1 | 1.255 (2) | C5—H5C | 0.9800 |
| O1—C1ii | 1.2524 (19) | C4—H4A | 0.9800 |
| O3—C3 | 1.250 (2) | C4—H4B | 0.9800 |
| N1—C3 | 1.305 (2) | C4—H4C | 0.9800 |
| N1—C5 | 1.457 (3) | ||
| O2i—Cd1—O2 | 173.16 (7) | C5—N1—C4 | 116.45 (17) |
| O2i—Cd1—O1i | 74.00 (5) | O3—C3—N1 | 124.40 (18) |
| O2—Cd1—O1i | 101.33 (5) | O3—C3—H3 | 117.8 |
| O2i—Cd1—O1 | 101.33 (5) | N1—C3—H3 | 117.8 |
| O2—Cd1—O1 | 74.00 (5) | O1ii—C1—O2 | 125.09 (16) |
| O1i—Cd1—O1 | 96.75 (8) | O1ii—C1—C1ii | 117.39 (18) |
| O2i—Cd1—O3 | 99.11 (5) | O2—C1—C1ii | 117.52 (17) |
| O2—Cd1—O3 | 86.02 (5) | N1—C5—H5A | 109.5 |
| O1i—Cd1—O3 | 93.24 (5) | N1—C5—H5B | 109.5 |
| O1—Cd1—O3 | 159.05 (5) | H5A—C5—H5B | 109.5 |
| O2i—Cd1—O3i | 86.02 (5) | N1—C5—H5C | 109.5 |
| O2—Cd1—O3i | 99.11 (5) | H5A—C5—H5C | 109.5 |
| O1i—Cd1—O3i | 159.05 (5) | H5B—C5—H5C | 109.5 |
| O1—Cd1—O3i | 93.24 (5) | N1—C4—H4A | 109.5 |
| O3—Cd1—O3i | 83.60 (7) | N1—C4—H4B | 109.5 |
| C1—O2—Cd1 | 115.51 (11) | H4A—C4—H4B | 109.5 |
| C1ii—O1—Cd1 | 115.58 (11) | N1—C4—H4C | 109.5 |
| C3—O3—Cd1 | 117.74 (12) | H4A—C4—H4C | 109.5 |
| C3—N1—C5 | 122.37 (16) | H4B—C4—H4C | 109.5 |
| C3—N1—C4 | 121.15 (17) | ||
| O1i—Cd1—O2—C1 | −93.56 (14) | O2—Cd1—O3—C3 | −43.38 (14) |
| O1—Cd1—O2—C1 | 0.29 (13) | O1i—Cd1—O3—C3 | −144.53 (14) |
| O3—Cd1—O2—C1 | 173.92 (14) | O1—Cd1—O3—C3 | −26.0 (2) |
| O3i—Cd1—O2—C1 | 91.07 (14) | O3i—Cd1—O3—C3 | 56.26 (12) |
| O2i—Cd1—O1—C1ii | 174.51 (13) | Cd1—O3—C3—N1 | 177.06 (15) |
| O2—Cd1—O1—C1ii | −0.35 (13) | C5—N1—C3—O3 | 178.7 (2) |
| O1i—Cd1—O1—C1ii | 99.55 (14) | C4—N1—C3—O3 | 1.1 (3) |
| O3—Cd1—O1—C1ii | −18.4 (2) | Cd1—O2—C1—O1ii | 179.68 (15) |
| O3i—Cd1—O1—C1ii | −98.90 (14) | Cd1—O2—C1—C1ii | −0.2 (3) |
| O2i—Cd1—O3—C3 | 141.17 (14) |
| Symmetry codes: (i) −x+1, y, −z+1/2; (ii) −x+1, −y, −z. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| C4—H4B···O1iii | 0.98 | 2.65 | 3.456 (2) | 140 |
| C4—H4C···O2iv | 0.98 | 2.70 | 3.516 (3) | 141 |
| C4—H4C···O1v | 0.98 | 2.63 | 3.468 (3) | 144 |
| C4—H4A···O3 | 0.98 | 2.36 | 2.775 (2) | 104 |
| Symmetry codes: (iii) x−1/2, y+1/2, −z+1/2; (iv) x, −y+1, z+1/2; (v) −x+1, y+1, −z+1/2. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| C4—H4B···O1i | 0.98 | 2.65 | 3.456 (2) | 140 |
| C4—H4C···O2ii | 0.98 | 2.70 | 3.516 (3) | 141 |
| C4—H4C···O1iii | 0.98 | 2.63 | 3.468 (3) | 144 |
| C4—H4A···O3 | 0.98 | 2.36 | 2.775 (2) | 104 |
| Symmetry codes: (i) x−1/2, y+1/2, −z+1/2; (ii) x, −y+1, z+1/2; (iii) −x+1, y+1, −z+1/2. |
We are grateful to Professor Lars Öhrström for his interest in this work and to Chalmers University of Technology for financial support.
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Crystal engineering of coordination polymers, based on pre-defined interactions of metal ions with organic spacers, is an area of research that has received substantial interest (Zaworotko, 2007). In this field, employing N– and/or O– donor ligands as bridging organic modules has been intensively implemented (Ockwig et al., 2005). Oxalate anions are known as chelating bis-bidentate ligands and many infinite two-dimensional and three-dimensional coordination polymers with a [MM'(ox)n]n' formula have been reported comprising two different and/or similar metal centres (Borel et al., 2006: Imaz et al., 2005: Xia et al., 2004: Decurtins et al., 1994). However, solvent ligation to the metal centres may result in structures with lower dimensionality (Prasad et al., 2002). Here we present a coordination chain based on bis-oxalato cadmium(II) with coordinated DMF solvent molecules.
A perspective drawing of the title compound with the atomic numbering scheme is shown in Figure 1. The CdII ions are situated on crystallographic twofold rotation axes while the oxalates are located on inversion centres. The CdII ion displays a distorted octahedral coordination geometry with two dimethylformamide molecules ligated to the CdII centre and the zigzag chain is built up from two oxalate units, linked via four O atoms to two CdII ions with a Cd—O distance in the range 2.262 (1)–2.297 (1) Å [(Cd—O)average = 2.275 (19) Å] (Figure 2). The intrachain Cd···Cd distance is 5.842 (1) Å. Contrary to many oxalate-metal chains which are linked to each other in one direction by π-π interactions (Ma et al., 2007) this structure exhibits only C—H···O hydrogen bonds which are both interchain and intrachain. The intermolecular hydrogen bonds build a stack of chains with a Cd···Cd distance of 8.006 (2) Å in the b axis direction and 8.569 (2) Å in the a axis direction. The three-dimensional architecture is maintained via coordination/covalent bonding in the c-direction and weaker C—H···O intermolecular hydrogen bonds in the ab-plane.