metal-organic compounds
catena-Poly[[[tetraaquacadmium(II)]-μ-3,3′-[p-phenylenebis(oxymethylene)]bis(1-pyridinioacetate)] dinitrate hemihydrate]
aCollege of Chemical Engineering, Zhengzhou University, Zhengzhou, Henan 450001, People's Republic of China, and bCollege of Chemical Engineering and Foods, Zhongzhou University, Zhengzhou, Henan 450044, People's Republic of China
*Correspondence e-mail: zzulhl@yahoo.com.cn
In the title polymeric coordination complex, {[Cd(C22H20N2O6)(H2O)4](NO3)2·0.5H2O}n, obtained from the self-assembly of the flexible double betaine 3,3′-[p-phenylenebis(oxymethylene)]bis(1-pyridinioacetate) with cadmium nitrate, both the octahedrally coordinated CdII cation and the substituted betaine ligand lie on inversion centres. The chains constructed through the trans-related acetate groups of the ligand are inter-connected via O—H⋯O hydrogen bonds involving coordinated aqua ligands, the nitrate anions and the partial-occupancy (0.25) water molecule of solvation, forming a three-dimensional structure.
Related literature
For betaine–metal coordination compexes, see: Zhang et al. (2004); Zhang & Mak (2004). For the structure of the copper(II) complex with the ligand employed here, see: Pan & Lian (2010).
Experimental
Crystal data
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Refinement
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Data collection: SMART (Bruker, 2001); cell SAINT (Bruker, 2001); data reduction: SAINT; 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: SHELXTL.
Supporting information
10.1107/S1600536810036317/zs2059sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536810036317/zs2059Isup2.hkl
An aqueous solution of 1,4-bis(3-picolyloxyl)benzene-N,N'-diacetate (dehydrated) (5 ml; 0.08 g, 0.2 mmol) and cadmium nitrate (0.093 g, 0.3 mmol) were combined and heated at 70° for 30 minutes and then filtered. Colorless block-shaped crystals were obtained upon slow evaporation of the filtrate at room temperature for several weeks (yield: ca. 46% based on L).
The H atoms of the water molecule were located in a difference map but were constrained in the
Other H atoms were positioned geometrically and refined using a riding model with C—H = 0.93, 0.97 Å and O–H = 0.85 Å, with Uiso(H) = 1.2Ueq(C).Data collection: SMART (Bruker, 2001); cell
SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 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: SHELXTL (Sheldrick, 2008).Fig. 1. A portion of the infinite chain of the title compound viewed along the a cell direction, showing atom numbering scheme. Atoms are drawn with 30% probability displacement ellipsoids. For symmetry code a: -x + 1, -y, -z. | |
Fig. 2. The three-dimensional structure of (I) formed through intermolecular hydrogen bonds, shown as dashed lines. |
[Cd(C22H20N2O6)(H2O)4](NO3)2·0.5H2O | F(000) = 738 |
Mr = 725.90 | Dx = 1.680 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 245 reflections |
a = 6.5627 (17) Å | θ = 2.0–27.5° |
b = 14.612 (2) Å | µ = 0.85 mm−1 |
c = 14.9730 (15) Å | T = 153 K |
β = 91.922 (19)° | Block, colorless |
V = 1435.0 (5) Å3 | 0.48 × 0.36 × 0.32 mm |
Z = 2 |
Bruker SMART CCD area-detector diffractometer | 2515 independent reflections |
Radiation source: fine-focus sealed tube | 1654 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.037 |
ϕ and ω scans | θmax = 25.0°, θmin = 2.0° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2004) | h = −1→7 |
Tmin = 0.687, Tmax = 0.774 | k = −1→17 |
3478 measured reflections | l = −17→17 |
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) = 0.081 | H-atom parameters constrained |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0152P)2 + 1.4665P] where P = (Fo2 + 2Fc2)/3 |
2515 reflections | (Δ/σ)max < 0.001 |
205 parameters | Δρmax = 0.34 e Å−3 |
6 restraints | Δρmin = −0.33 e Å−3 |
[Cd(C22H20N2O6)(H2O)4](NO3)2·0.5H2O | V = 1435.0 (5) Å3 |
Mr = 725.90 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 6.5627 (17) Å | µ = 0.85 mm−1 |
b = 14.612 (2) Å | T = 153 K |
c = 14.9730 (15) Å | 0.48 × 0.36 × 0.32 mm |
β = 91.922 (19)° |
Bruker SMART CCD area-detector diffractometer | 2515 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2004) | 1654 reflections with I > 2σ(I) |
Tmin = 0.687, Tmax = 0.774 | Rint = 0.037 |
3478 measured reflections |
R[F2 > 2σ(F2)] = 0.045 | 6 restraints |
wR(F2) = 0.081 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.34 e Å−3 |
2515 reflections | Δρmin = −0.33 e Å−3 |
205 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 | Occ. (<1) | |
Cd1 | 0.0000 | 0.5000 | 0.0000 | 0.04421 (19) | |
N2 | 0.0260 (8) | 0.3049 (4) | 0.3014 (3) | 0.0512 (13) | |
O4 | 0.1818 (7) | 0.2675 (4) | 0.2799 (3) | 0.0978 (17) | |
O5 | −0.0681 (8) | 0.2698 (4) | 0.3614 (3) | 0.111 (2) | |
O6 | −0.0265 (9) | 0.3747 (4) | 0.2635 (4) | 0.113 (2) | |
N1 | −0.3871 (6) | 0.2278 (3) | 0.0648 (2) | 0.0288 (9) | |
O1 | −0.2220 (5) | 0.3883 (2) | 0.0220 (2) | 0.0481 (10) | |
O2 | −0.4430 (5) | 0.4167 (2) | −0.0904 (2) | 0.0446 (9) | |
O3 | 0.1499 (5) | 0.0941 (2) | 0.0419 (2) | 0.0441 (9) | |
O1W | 0.2047 (5) | 0.4226 (2) | 0.1045 (3) | 0.0592 (11) | |
H1WA | 0.1390 | 0.4146 | 0.1518 | 0.071* | |
H1WB | 0.2900 | 0.4640 | 0.1198 | 0.071* | |
O2W | −0.1374 (5) | 0.5844 (2) | 0.1150 (2) | 0.0579 (11) | |
H2WA | −0.2639 | 0.5886 | 0.1015 | 0.069* | |
H2WB | −0.1002 | 0.6395 | 0.1239 | 0.069* | |
C1 | −0.3701 (7) | 0.3696 (3) | −0.0283 (3) | 0.0322 (12) | |
C2 | −0.4697 (7) | 0.2772 (3) | −0.0141 (3) | 0.0349 (13) | |
H2A | −0.6149 | 0.2862 | −0.0077 | 0.042* | |
H2B | −0.4516 | 0.2397 | −0.0668 | 0.042* | |
C3 | −0.2120 (7) | 0.1805 (3) | 0.0579 (3) | 0.0311 (11) | |
H3A | −0.1448 | 0.1803 | 0.0042 | 0.037* | |
C4 | −0.1326 (7) | 0.1328 (3) | 0.1296 (3) | 0.0284 (11) | |
C5 | −0.2363 (8) | 0.1349 (3) | 0.2090 (3) | 0.0382 (12) | |
H5A | −0.1861 | 0.1026 | 0.2585 | 0.046* | |
C6 | −0.4124 (8) | 0.1845 (4) | 0.2142 (3) | 0.0424 (14) | |
H6A | −0.4818 | 0.1864 | 0.2673 | 0.051* | |
C7 | −0.4854 (7) | 0.2311 (3) | 0.1412 (3) | 0.0366 (12) | |
H7A | −0.6043 | 0.2654 | 0.1447 | 0.044* | |
C8 | 0.0605 (7) | 0.0779 (4) | 0.1255 (3) | 0.0411 (13) | |
H8A | 0.1545 | 0.0958 | 0.1737 | 0.049* | |
H8B | 0.0305 | 0.0133 | 0.1319 | 0.049* | |
C9 | 0.3246 (7) | 0.0448 (3) | 0.0241 (3) | 0.0321 (12) | |
C10 | 0.4000 (7) | 0.0579 (3) | −0.0602 (3) | 0.0350 (12) | |
H10A | 0.3327 | 0.0966 | −0.1006 | 0.042* | |
C11 | 0.4228 (7) | −0.0127 (4) | 0.0841 (3) | 0.0364 (12) | |
H11A | 0.3712 | −0.0215 | 0.1406 | 0.044* | |
O3W | 0.424 (2) | −0.0647 (10) | 0.2940 (8) | 0.059 (4) | 0.25 |
H3WA | 0.4185 | −0.0133 | 0.3204 | 0.070* | 0.25 |
H3WB | 0.3284 | −0.1040 | 0.2933 | 0.070* | 0.25 |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cd1 | 0.0345 (3) | 0.0305 (3) | 0.0675 (4) | −0.0037 (4) | 0.0010 (3) | 0.0071 (4) |
N2 | 0.053 (3) | 0.055 (3) | 0.046 (3) | −0.005 (3) | 0.003 (3) | −0.017 (3) |
O4 | 0.076 (3) | 0.102 (4) | 0.116 (4) | 0.035 (3) | 0.028 (3) | −0.002 (3) |
O5 | 0.129 (5) | 0.139 (5) | 0.070 (3) | −0.062 (4) | 0.055 (3) | −0.036 (3) |
O6 | 0.153 (5) | 0.070 (3) | 0.114 (4) | 0.043 (4) | −0.018 (4) | 0.003 (3) |
N1 | 0.026 (2) | 0.030 (2) | 0.031 (2) | −0.0062 (19) | 0.0017 (19) | −0.0014 (18) |
O1 | 0.044 (2) | 0.045 (2) | 0.054 (2) | −0.0203 (19) | −0.011 (2) | 0.0134 (19) |
O2 | 0.047 (2) | 0.039 (2) | 0.048 (2) | −0.0017 (19) | −0.0003 (19) | 0.0126 (19) |
O3 | 0.035 (2) | 0.049 (2) | 0.049 (2) | 0.0190 (18) | 0.0109 (17) | 0.0077 (19) |
O1W | 0.053 (2) | 0.049 (2) | 0.075 (3) | 0.006 (2) | −0.014 (2) | 0.000 (2) |
O2W | 0.046 (2) | 0.052 (2) | 0.075 (3) | 0.000 (2) | −0.007 (2) | −0.010 (2) |
C1 | 0.028 (3) | 0.036 (3) | 0.033 (3) | −0.002 (2) | 0.006 (2) | −0.003 (2) |
C2 | 0.031 (3) | 0.034 (2) | 0.040 (3) | −0.001 (3) | −0.003 (3) | 0.005 (3) |
C3 | 0.026 (3) | 0.032 (3) | 0.035 (3) | −0.003 (2) | 0.005 (2) | −0.004 (2) |
C4 | 0.024 (2) | 0.026 (2) | 0.036 (3) | −0.006 (2) | 0.003 (2) | −0.004 (2) |
C5 | 0.039 (3) | 0.039 (3) | 0.036 (3) | 0.000 (3) | −0.003 (3) | 0.003 (3) |
C6 | 0.045 (3) | 0.053 (3) | 0.030 (3) | 0.000 (3) | 0.009 (3) | −0.002 (3) |
C7 | 0.032 (3) | 0.037 (3) | 0.042 (3) | 0.002 (2) | 0.013 (3) | −0.005 (3) |
C8 | 0.032 (3) | 0.044 (3) | 0.048 (3) | 0.003 (3) | 0.007 (3) | 0.005 (3) |
C9 | 0.023 (3) | 0.029 (2) | 0.045 (3) | 0.005 (2) | −0.001 (2) | −0.007 (2) |
C10 | 0.036 (3) | 0.029 (3) | 0.040 (3) | 0.000 (2) | −0.006 (3) | 0.000 (2) |
C11 | 0.031 (2) | 0.039 (3) | 0.039 (3) | 0.001 (3) | 0.004 (2) | −0.001 (3) |
O3W | 0.089 (12) | 0.050 (9) | 0.037 (8) | −0.006 (9) | 0.000 (9) | −0.016 (8) |
Cd1—O1i | 2.219 (3) | C2—H2A | 0.9700 |
Cd1—O1 | 2.219 (3) | C2—H2B | 0.9700 |
Cd1—O1W | 2.321 (3) | C3—C4 | 1.369 (6) |
Cd1—O1Wi | 2.321 (3) | C3—H3A | 0.9300 |
Cd1—O2Wi | 2.324 (4) | C4—C5 | 1.390 (6) |
Cd1—O2W | 2.324 (4) | C4—C8 | 1.503 (6) |
N2—O6 | 1.212 (6) | C5—C6 | 1.369 (6) |
N2—O4 | 1.213 (6) | C5—H5A | 0.9300 |
N2—O5 | 1.220 (6) | C6—C7 | 1.360 (7) |
N1—C7 | 1.334 (5) | C6—H6A | 0.9300 |
N1—C3 | 1.348 (5) | C7—H7A | 0.9300 |
N1—C2 | 1.472 (6) | C8—H8A | 0.9700 |
O1—C1 | 1.240 (5) | C8—H8B | 0.9700 |
O2—C1 | 1.240 (5) | C9—C11 | 1.375 (6) |
O3—C9 | 1.387 (5) | C9—C10 | 1.384 (6) |
O3—C8 | 1.420 (5) | C10—C11ii | 1.394 (6) |
O1W—H1WA | 0.8501 | C10—H10A | 0.9300 |
O1W—H1WB | 0.8501 | C11—C10ii | 1.394 (6) |
O2W—H2WA | 0.8500 | C11—H11A | 0.9300 |
O2W—H2WB | 0.8500 | O3W—H3WA | 0.8499 |
C1—C2 | 1.518 (6) | O3W—H3WB | 0.8500 |
O1i—Cd1—O1 | 180.00 (18) | N1—C2—H2B | 108.9 |
O1i—Cd1—O1W | 95.17 (13) | C1—C2—H2B | 108.9 |
O1—Cd1—O1W | 84.83 (13) | H2A—C2—H2B | 107.7 |
O1i—Cd1—O1Wi | 84.83 (13) | N1—C3—C4 | 120.3 (4) |
O1—Cd1—O1Wi | 95.17 (13) | N1—C3—H3A | 119.9 |
O1W—Cd1—O1Wi | 180.0 | C4—C3—H3A | 119.9 |
O1i—Cd1—O2Wi | 90.43 (13) | C3—C4—C5 | 118.4 (4) |
O1—Cd1—O2Wi | 89.57 (13) | C3—C4—C8 | 122.6 (4) |
O1W—Cd1—O2Wi | 90.61 (13) | C5—C4—C8 | 119.0 (4) |
O1Wi—Cd1—O2Wi | 89.39 (13) | C6—C5—C4 | 119.9 (5) |
O1i—Cd1—O2W | 89.57 (13) | C6—C5—H5A | 120.1 |
O1—Cd1—O2W | 90.43 (13) | C4—C5—H5A | 120.1 |
O1W—Cd1—O2W | 89.39 (13) | C7—C6—C5 | 119.7 (5) |
O1Wi—Cd1—O2W | 90.61 (13) | C7—C6—H6A | 120.2 |
O2Wi—Cd1—O2W | 180.00 (15) | C5—C6—H6A | 120.2 |
O6—N2—O4 | 119.0 (6) | N1—C7—C6 | 120.3 (5) |
O6—N2—O5 | 123.8 (6) | N1—C7—H7A | 119.9 |
O4—N2—O5 | 117.2 (6) | C6—C7—H7A | 119.9 |
C7—N1—C3 | 121.5 (4) | O3—C8—C4 | 108.7 (4) |
C7—N1—C2 | 119.7 (4) | O3—C8—H8A | 109.9 |
C3—N1—C2 | 118.8 (4) | C4—C8—H8A | 109.9 |
C1—O1—Cd1 | 125.2 (3) | O3—C8—H8B | 109.9 |
C9—O3—C8 | 116.8 (4) | C4—C8—H8B | 109.9 |
Cd1—O1W—H1WA | 109.3 | H8A—C8—H8B | 108.3 |
Cd1—O1W—H1WB | 101.3 | C11—C9—C10 | 120.4 (4) |
H1WA—O1W—H1WB | 102.8 | C11—C9—O3 | 124.4 (4) |
Cd1—O2W—H2WA | 105.3 | C10—C9—O3 | 115.2 (4) |
Cd1—O2W—H2WB | 120.1 | C9—C10—C11ii | 119.7 (4) |
H2WA—O2W—H2WB | 103.9 | C9—C10—H10A | 120.1 |
O1—C1—O2 | 127.4 (5) | C11ii—C10—H10A | 120.1 |
O1—C1—C2 | 116.3 (5) | C9—C11—C10ii | 119.9 (4) |
O2—C1—C2 | 116.2 (4) | C9—C11—H11A | 120.1 |
N1—C2—C1 | 113.5 (4) | C10ii—C11—H11A | 120.1 |
N1—C2—H2A | 108.9 | H3WA—O3W—H3WB | 124.1 |
C1—C2—H2A | 108.9 | ||
O1W—Cd1—O1—C1 | −163.1 (4) | C8—C4—C5—C6 | 179.9 (5) |
O1Wi—Cd1—O1—C1 | 16.9 (4) | C4—C5—C6—C7 | 0.4 (8) |
O2Wi—Cd1—O1—C1 | −72.4 (4) | C3—N1—C7—C6 | −1.5 (7) |
O2W—Cd1—O1—C1 | 107.6 (4) | C2—N1—C7—C6 | 178.9 (4) |
Cd1—O1—C1—O2 | −13.1 (7) | C5—C6—C7—N1 | 0.6 (8) |
Cd1—O1—C1—C2 | 164.9 (3) | C9—O3—C8—C4 | −176.5 (4) |
C7—N1—C2—C1 | 98.2 (5) | C3—C4—C8—O3 | 6.8 (6) |
C3—N1—C2—C1 | −81.5 (5) | C5—C4—C8—O3 | −173.7 (4) |
O1—C1—C2—N1 | 6.3 (6) | C8—O3—C9—C11 | −4.8 (7) |
O2—C1—C2—N1 | −175.4 (4) | C8—O3—C9—C10 | 176.0 (4) |
C7—N1—C3—C4 | 1.3 (7) | C11—C9—C10—C11ii | −0.3 (8) |
C2—N1—C3—C4 | −179.0 (4) | O3—C9—C10—C11ii | 178.9 (4) |
N1—C3—C4—C5 | −0.3 (7) | C10—C9—C11—C10ii | 0.3 (8) |
N1—C3—C4—C8 | 179.2 (4) | O3—C9—C11—C10ii | −178.8 (4) |
C3—C4—C5—C6 | −0.6 (7) |
Symmetry codes: (i) −x, −y+1, −z; (ii) −x+1, −y, −z. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1WA···O6 | 0.85 | 2.11 | 2.950 (7) | 172 |
O1W—H1WB···O2i | 0.85 | 2.07 | 2.832 (5) | 150 |
O1W—H1WB···O3Wiii | 0.85 | 2.28 | 2.835 (16) | 123 |
O2W—H2WA···O2iv | 0.85 | 1.93 | 2.766 (5) | 169 |
O2W—H2WB···O5v | 0.85 | 2.21 | 3.041 (7) | 166 |
O2W—H2WB···O4v | 0.85 | 2.43 | 3.122 (6) | 139 |
O3W—H3WA···O2vi | 0.85 | 2.13 | 2.886 (14) | 149 |
O3W—H3WA···O2Wvii | 0.85 | 2.55 | 3.211 (15) | 136 |
O3W—H3WB···O6vii | 0.85 | 2.15 | 2.859 (16) | 141 |
Symmetry codes: (i) −x, −y+1, −z; (iii) −x+1, y+1/2, −z+1/2; (iv) −x−1, −y+1, −z; (v) −x, y+1/2, −z+1/2; (vi) x+1, −y+1/2, z+1/2; (vii) −x, y−1/2, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | [Cd(C22H20N2O6)(H2O)4](NO3)2·0.5H2O |
Mr | 725.90 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 153 |
a, b, c (Å) | 6.5627 (17), 14.612 (2), 14.9730 (15) |
β (°) | 91.922 (19) |
V (Å3) | 1435.0 (5) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.85 |
Crystal size (mm) | 0.48 × 0.36 × 0.32 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2004) |
Tmin, Tmax | 0.687, 0.774 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3478, 2515, 1654 |
Rint | 0.037 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.081, 1.02 |
No. of reflections | 2515 |
No. of parameters | 205 |
No. of restraints | 6 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.34, −0.33 |
Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1WA···O6 | 0.85 | 2.11 | 2.950 (7) | 171.8 |
O1W—H1WB···O2i | 0.85 | 2.07 | 2.832 (5) | 149.6 |
O1W—H1WB···O3Wii | 0.85 | 2.28 | 2.835 (16) | 123.0 |
O2W—H2WA···O2iii | 0.85 | 1.93 | 2.766 (5) | 169.1 |
O2W—H2WB···O5iv | 0.85 | 2.21 | 3.041 (7) | 166.3 |
O2W—H2WB···O4iv | 0.85 | 2.43 | 3.122 (6) | 138.9 |
O3W—H3WA···O2v | 0.85 | 2.13 | 2.886 (14) | 148.7 |
O3W—H3WA···O2Wvi | 0.85 | 2.55 | 3.211 (15) | 135.5 |
O3W—H3WB···O6vi | 0.85 | 2.15 | 2.859 (16) | 140.5 |
Symmetry codes: (i) −x, −y+1, −z; (ii) −x+1, y+1/2, −z+1/2; (iii) −x−1, −y+1, −z; (iv) −x, y+1/2, −z+1/2; (v) x+1, −y+1/2, z+1/2; (vi) −x, y−1/2, −z+1/2. |
Acknowledgements
Financial support from Zhengzhou University is greatly appreciated.
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The coordinative bond approach has been widely used in the construction of supramolecular coordination compounds. As a parallel development, it is possible to use highly directional hydrogen bonds as a means of controlling self-assembly. Double betaines, comprising two betaine moieties and having two terminal anionic carboxylate substituent groups are of great utility for linkage to a broad array of metal ions, generating a variey of supramolecular entities, ranging from discrete complex units, through networks linked by hydrogen bonding, to metallo-supramolecular systems (Zhang et al., 2004); Zhang & Mak, 2004). The double betaine ligand 1,4-bis(3-picolyloxyl)benzene-N,N'-diacetate (L) has provided the structure of a polymeric complex with CuII (Pan & Lian, 2010). Our reaction of L with cadmium nitrate gave the polymeric coordination complex [[Cd2(L)(H2O)4]n 2n(NO3) 0.5n(H2O)], the title compound (I) and the structure is reported here. In (I), the CdII cations have octahedral stereochemistry and lie on crystallographic inversion centres and are coordinated by two trans-related acetato-O donors [Cd–O, 2.219 (3) Å] and four water molecules [Cd–O, 2.321 (3), 2.324 (4) Å] (Fig. 1). The substituted betaine ligand also lies across a crysallographic inversion centre, forming an infinite zigzag chain structure. These chains are further inter-connected by intermolecular hydrogen-bonding interactions involving the nitrate anions, the coordinated aqua ligands and the partial-occupancy (S.O.F = 0.25) water molecule of solvation (Table 1), to form a three-dimensional structure (Fig. 2).