Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807033508/rk2025sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807033508/rk2025Isup2.hkl |
CCDC reference: 657588
A mixture of CdCl2 (1 mmol), 1-methyl-3-carboxymethylimidazole ion liquid (1 mmol) and water (20 ml) was sealed in a 25 ml Teflon-lined stainless steel reactor and heated at 393 K for 48 h. A colourless solution was obtained after cooling the reaction to room temperature, colourless single crystals were obtained after two weeks.
The structure was solved by direct methods and successive Fourier difference synthesis. The H atoms bonded to C atoms were positioned geometrically and refined using a riding model [C—H = 0.97 (2) Å and Uiso(H) = 1.2Ueq(C)]. The H atoms bonded to O atoms were located in a difference Fourier maps and refined with O—H distance restraints of 0.85 (2) Å and Uiso(H) = 1.2Ueq(O).
In recent years, there has been an increasing interest in the coordination chemistry of cadmium due to the increased recognition of it's role in biological organisms and molecular-based materials (Jian et al., 2006). Here, we report a novel one-dimensional Cd string complex (I), which contains one [Cd2Cl5(H2O)]- anion and one 1-methyl-3-carboxymethylimidazole cation in the asymmetric unit, (Fig.1).
The inorganic chain is formed by two paralleled chains of corner-sharing [Cd2Cl2] quadrangular, which are displaced by half distance of Cd1—Cd2 and connected by tridentate bridging chlorine atoms. In the crystal structure, two independent cadmium atoms are present, which are connected by a bidentate and a tridentate bridging chlorine atom. The six-coordination is completed on the Cd(1) atom by a tridentate bridging chlorine atom and a coordinated water molecule, while on the Cd(2) atom by a tridentate bridging and a terminal chlorine atom. In each one of paralled chains, the terminal atoms (chlorine atom and water molecule) are in cis-position to each other, but in trans-position to the terminal atoms in the other paralled chain.
Each Cd atom shows a distorted octahedral geometry, gives rise to a polymeric linear chain of edge-sharing octahedra running along the a axis. Cd—C1 distances vary according to the different bonding mode of the C1 atoms; their values normally increasing in the order terminal < dibridged < tribridged, which are in agreement with the compound repoted by Corradi (Corradi et al., 1993).
Imidazole cations form one-dimensional chains next to the inorganic chain via π-π stacking interactions. Furthermore, there are O–H···Cl and O–H···O intermolecule hydrogen bond involving coordinated water O1w atom and terminate Cl atom, as well as carboxyl O1 atom and carboxyl O2 atom (see table), which stabilize the three-dimensional network.
For related literature, see: Corrad et al. (1993); Jian et al. (2006).
Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2002); software used to prepare material for publication: SHELXL97.
Fig. 1. A view of the molecule of (I) showing the atom-labelling scheme, with displacement ellipsoids drawn at the 30% probability. |
(C6H9N2O2)[Cd2Cl5(H2O)] | Z = 2 |
Mr = 561.24 | F(000) = 532 |
Triclinic, P1 | Dx = 2.411 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.580 (2) Å | Cell parameters from 5396 reflections |
b = 10.339 (3) Å | θ = 2.5–27.8° |
c = 10.371 (3) Å | µ = 3.61 mm−1 |
α = 74.593 (15)° | T = 296 K |
β = 81.568 (17)° | Block, colourless |
γ = 83.781 (16)° | 0.56 × 0.20 × 0.10 mm |
V = 773.0 (4) Å3 |
Bruker SMART CCD area-detector diffractometer | 3446 independent reflections |
Radiation source: fine-focus sealed tube | 3191 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.022 |
ω scans | θmax = 27.8°, θmin = 2.5° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −9→9 |
Tmin = 0.424, Tmax = 0.697 | k = −13→13 |
9462 measured reflections | l = −13→13 |
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)] = 0.021 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.056 | H-atom parameters constrained |
S = 1.01 | w = 1/[σ2(Fo2) + (0.033P)2 + 0.3014P] where P = (Fo2 + 2Fc2)/3 |
3446 reflections | (Δ/σ)max = 0.002 |
163 parameters | Δρmax = 0.52 e Å−3 |
0 restraints | Δρmin = −0.90 e Å−3 |
(C6H9N2O2)[Cd2Cl5(H2O)] | γ = 83.781 (16)° |
Mr = 561.24 | V = 773.0 (4) Å3 |
Triclinic, P1 | Z = 2 |
a = 7.580 (2) Å | Mo Kα radiation |
b = 10.339 (3) Å | µ = 3.61 mm−1 |
c = 10.371 (3) Å | T = 296 K |
α = 74.593 (15)° | 0.56 × 0.20 × 0.10 mm |
β = 81.568 (17)° |
Bruker SMART CCD area-detector diffractometer | 3446 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 3191 reflections with I > 2σ(I) |
Tmin = 0.424, Tmax = 0.697 | Rint = 0.022 |
9462 measured reflections |
R[F2 > 2σ(F2)] = 0.021 | 0 restraints |
wR(F2) = 0.056 | H-atom parameters constrained |
S = 1.01 | Δρmax = 0.52 e Å−3 |
3446 reflections | Δρmin = −0.90 e Å−3 |
163 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 > 2σ(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 | −0.65421 (2) | 1.144477 (16) | 0.049066 (16) | 0.02828 (6) | |
Cd2 | −0.84758 (2) | 0.825988 (16) | −0.030118 (16) | 0.02783 (6) | |
C1 | −0.8088 (3) | 1.0934 (2) | 0.5265 (2) | 0.0318 (5) | |
C2 | −0.6479 (3) | 1.1611 (2) | 0.5415 (2) | 0.0322 (5) | |
H2A | −0.6095 | 1.1199 | 0.6293 | 0.039* | |
H2B | −0.5503 | 1.1475 | 0.4736 | 0.039* | |
C3 | −0.7179 (4) | 1.3985 (2) | 0.4081 (3) | 0.0441 (6) | |
H3A | −0.7117 | 1.3816 | 0.3238 | 0.053* | |
C4 | −0.7576 (4) | 1.5190 (3) | 0.4378 (3) | 0.0440 (6) | |
H4A | −0.7835 | 1.6008 | 0.3774 | 0.053* | |
C5 | −0.7114 (3) | 1.3677 (2) | 0.6260 (2) | 0.0331 (5) | |
H5A | −0.7005 | 1.3272 | 0.7162 | 0.040* | |
C6 | −0.7922 (5) | 1.5991 (3) | 0.6535 (3) | 0.0551 (8) | |
H6A | −0.7777 | 1.5570 | 0.7460 | 0.083* | |
H6B | −0.9130 | 1.6369 | 0.6472 | 0.083* | |
H6C | −0.7115 | 1.6692 | 0.6188 | 0.083* | |
N1 | −0.7525 (3) | 1.49781 (19) | 0.5738 (2) | 0.0362 (5) | |
N2 | −0.6886 (3) | 1.30571 (17) | 0.52722 (18) | 0.0308 (4) | |
O1 | −0.7649 (2) | 0.97628 (16) | 0.50150 (18) | 0.0440 (5) | |
H1 | −0.8520 | 0.9380 | 0.4935 | 0.053* | |
O1W | −0.6345 (3) | 1.37162 (17) | −0.07118 (18) | 0.0430 (4) | |
H1WA | −0.5308 | 1.3949 | −0.0691 | 0.052* | |
H1WB | −0.7130 | 1.4161 | −0.0313 | 0.052* | |
O2 | −0.9607 (2) | 1.14584 (16) | 0.53634 (17) | 0.0381 (4) | |
Cl1 | −0.43258 (8) | 1.17746 (6) | 0.20317 (6) | 0.03400 (13) | |
Cl2 | −0.62407 (8) | 0.87957 (5) | 0.13734 (5) | 0.02852 (11) | |
Cl3 | −1.13417 (7) | 0.89355 (5) | 0.12270 (5) | 0.02748 (11) | |
Cl4 | −1.06544 (8) | 0.81267 (6) | −0.19757 (6) | 0.03600 (13) | |
Cl5 | −0.80425 (10) | 0.58296 (6) | 0.09300 (7) | 0.04500 (16) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cd1 | 0.02405 (10) | 0.03030 (9) | 0.03304 (10) | −0.00022 (6) | −0.00257 (7) | −0.01366 (7) |
Cd2 | 0.02290 (10) | 0.02877 (9) | 0.03250 (10) | 0.00080 (6) | −0.00173 (7) | −0.01092 (7) |
C1 | 0.0441 (14) | 0.0252 (10) | 0.0267 (11) | 0.0008 (9) | −0.0075 (10) | −0.0073 (8) |
C2 | 0.0343 (13) | 0.0279 (10) | 0.0343 (12) | 0.0020 (9) | −0.0016 (10) | −0.0109 (9) |
C3 | 0.0650 (18) | 0.0354 (12) | 0.0289 (12) | −0.0021 (12) | −0.0034 (12) | −0.0048 (10) |
C4 | 0.0580 (18) | 0.0327 (12) | 0.0378 (13) | −0.0015 (11) | −0.0099 (12) | −0.0013 (10) |
C5 | 0.0410 (14) | 0.0289 (10) | 0.0299 (11) | −0.0022 (9) | −0.0038 (10) | −0.0087 (9) |
C6 | 0.075 (2) | 0.0373 (14) | 0.0616 (18) | 0.0083 (13) | −0.0160 (16) | −0.0276 (13) |
N1 | 0.0445 (13) | 0.0269 (9) | 0.0393 (11) | 0.0003 (8) | −0.0078 (9) | −0.0118 (8) |
N2 | 0.0376 (11) | 0.0258 (9) | 0.0286 (9) | −0.0020 (7) | −0.0010 (8) | −0.0082 (7) |
O1 | 0.0427 (11) | 0.0308 (8) | 0.0657 (13) | 0.0035 (7) | −0.0139 (10) | −0.0231 (8) |
O1W | 0.0531 (12) | 0.0322 (8) | 0.0447 (10) | 0.0042 (8) | −0.0075 (9) | −0.0140 (7) |
O2 | 0.0369 (10) | 0.0319 (8) | 0.0479 (10) | 0.0032 (7) | −0.0071 (8) | −0.0153 (7) |
Cl1 | 0.0270 (3) | 0.0497 (3) | 0.0301 (3) | −0.0041 (2) | −0.0004 (2) | −0.0195 (2) |
Cl2 | 0.0282 (3) | 0.0285 (2) | 0.0297 (3) | −0.00082 (19) | −0.0014 (2) | −0.0105 (2) |
Cl3 | 0.0262 (3) | 0.0310 (2) | 0.0255 (2) | −0.00225 (19) | −0.0002 (2) | −0.00919 (19) |
Cl4 | 0.0278 (3) | 0.0518 (3) | 0.0336 (3) | 0.0035 (2) | −0.0023 (2) | −0.0231 (3) |
Cl5 | 0.0624 (4) | 0.0270 (3) | 0.0432 (3) | −0.0011 (3) | −0.0051 (3) | −0.0063 (2) |
Cd1—O1W | 2.3575 (18) | C3—N2 | 1.379 (3) |
Cd1—Cl4i | 2.5066 (9) | C3—H3A | 0.9300 |
Cd1—Cl1 | 2.5873 (8) | C4—N1 | 1.374 (4) |
Cd1—Cl2 | 2.6430 (9) | C4—H4A | 0.9300 |
Cd1—Cl2ii | 2.6822 (9) | C5—N2 | 1.328 (3) |
Cd1—Cl3i | 2.6922 (8) | C5—N1 | 1.331 (3) |
Cd2—Cl5 | 2.5082 (9) | C5—H5A | 0.9300 |
Cd2—Cl1ii | 2.5753 (9) | C6—N1 | 1.479 (3) |
Cd2—Cl4 | 2.6037 (9) | C6—H6A | 0.9600 |
Cd2—Cl3 | 2.6398 (9) | C6—H6B | 0.9600 |
Cd2—Cl2 | 2.7876 (8) | C6—H6C | 0.9600 |
Cd2—Cl3i | 2.7968 (10) | O1—H1 | 0.8303 |
C1—O2 | 1.221 (3) | O1W—H1WA | 0.8511 |
C1—O1 | 1.303 (2) | O1W—H1WB | 0.8405 |
C1—C2 | 1.517 (3) | Cl1—Cd2ii | 2.5753 (9) |
C2—N2 | 1.465 (3) | Cl2—Cd1ii | 2.6822 (9) |
C2—H2A | 0.9700 | Cl3—Cd1i | 2.6922 (8) |
C2—H2B | 0.9700 | Cl3—Cd2i | 2.7968 (10) |
C3—C4 | 1.353 (3) | Cl4—Cd1i | 2.5066 (9) |
O1W—Cd1—Cl4i | 94.81 (5) | N2—C2—H2B | 109.3 |
O1W—Cd1—Cl1 | 89.02 (5) | C1—C2—H2B | 109.3 |
Cl4i—Cd1—Cl1 | 96.61 (3) | H2A—C2—H2B | 107.9 |
O1W—Cd1—Cl2 | 166.91 (5) | C4—C3—N2 | 106.7 (2) |
Cl4i—Cd1—Cl2 | 97.76 (3) | C4—C3—H3A | 126.7 |
Cl1—Cd1—Cl2 | 93.17 (3) | N2—C3—H3A | 126.7 |
O1W—Cd1—Cl2ii | 79.77 (5) | C3—C4—N1 | 107.2 (2) |
Cl4i—Cd1—Cl2ii | 172.27 (2) | C3—C4—H4A | 126.4 |
Cl1—Cd1—Cl2ii | 88.85 (3) | N1—C4—H4A | 126.4 |
Cl2—Cd1—Cl2ii | 87.37 (3) | N2—C5—N1 | 108.3 (2) |
O1W—Cd1—Cl3i | 90.75 (5) | N2—C5—H5A | 125.8 |
Cl4i—Cd1—Cl3i | 87.22 (3) | N1—C5—H5A | 125.8 |
Cl1—Cd1—Cl3i | 176.167 (17) | N1—C6—H6A | 109.5 |
Cl2—Cd1—Cl3i | 86.20 (2) | N1—C6—H6B | 109.5 |
Cl2ii—Cd1—Cl3i | 87.34 (3) | H6A—C6—H6B | 109.5 |
Cl5—Cd2—Cl1ii | 95.21 (3) | N1—C6—H6C | 109.5 |
Cl5—Cd2—Cl4 | 101.03 (3) | H6A—C6—H6C | 109.5 |
Cl1ii—Cd2—Cl4 | 93.72 (3) | H6B—C6—H6C | 109.5 |
Cl5—Cd2—Cl3 | 98.51 (3) | C5—N1—C4 | 108.8 (2) |
Cl1ii—Cd2—Cl3 | 166.00 (2) | C5—N1—C6 | 124.2 (2) |
Cl4—Cd2—Cl3 | 86.37 (3) | C4—N1—C6 | 127.0 (2) |
Cl5—Cd2—Cl2 | 86.97 (3) | C5—N2—C3 | 109.01 (19) |
Cl1ii—Cd2—Cl2 | 86.83 (3) | C5—N2—C2 | 126.23 (19) |
Cl4—Cd2—Cl2 | 171.891 (18) | C3—N2—C2 | 124.70 (19) |
Cl3—Cd2—Cl2 | 91.15 (3) | C1—O1—H1 | 113.3 |
Cl5—Cd2—Cl3i | 168.10 (2) | Cd1—O1W—H1WA | 108.9 |
Cl1ii—Cd2—Cl3i | 87.15 (3) | Cd1—O1W—H1WB | 106.3 |
Cl4—Cd2—Cl3i | 90.43 (3) | H1WA—O1W—H1WB | 110.4 |
Cl3—Cd2—Cl3i | 78.85 (3) | Cd2ii—Cl1—Cd1 | 95.48 (3) |
Cl2—Cd2—Cl3i | 81.51 (2) | Cd1—Cl2—Cd1ii | 92.63 (3) |
O2—C1—O1 | 125.2 (2) | Cd1—Cl2—Cd2 | 96.80 (2) |
O2—C1—C2 | 122.34 (19) | Cd1ii—Cl2—Cd2 | 88.60 (3) |
O1—C1—C2 | 112.4 (2) | Cd2—Cl3—Cd1i | 90.45 (3) |
N2—C2—C1 | 111.75 (18) | Cd2—Cl3—Cd2i | 101.15 (3) |
N2—C2—H2A | 109.3 | Cd1i—Cl3—Cd2i | 95.46 (2) |
C1—C2—H2A | 109.3 | Cd1i—Cl4—Cd2 | 95.57 (3) |
O2—C1—C2—N2 | −17.3 (3) | Cl2ii—Cd1—Cl2—Cd2 | −88.90 (3) |
O1—C1—C2—N2 | 162.16 (18) | Cl3i—Cd1—Cl2—Cd2 | −1.392 (15) |
N2—C3—C4—N1 | −0.2 (3) | Cl5—Cd2—Cl2—Cd1 | −175.66 (2) |
N2—C5—N1—C4 | 0.5 (3) | Cl1ii—Cd2—Cl2—Cd1 | 88.94 (3) |
N2—C5—N1—C6 | 178.5 (2) | Cl3—Cd2—Cl2—Cd1 | −77.20 (3) |
C3—C4—N1—C5 | −0.2 (4) | Cl3i—Cd2—Cl2—Cd1 | 1.352 (14) |
C3—C4—N1—C6 | −178.0 (2) | Cl5—Cd2—Cl2—Cd1ii | 91.85 (3) |
N1—C5—N2—C3 | −0.7 (3) | Cl1ii—Cd2—Cl2—Cd1ii | −3.542 (16) |
N1—C5—N2—C2 | −177.8 (2) | Cl3—Cd2—Cl2—Cd1ii | −169.681 (17) |
C4—C3—N2—C5 | 0.6 (3) | Cl3i—Cd2—Cl2—Cd1ii | −91.13 (3) |
C4—C3—N2—C2 | 177.7 (2) | Cl5—Cd2—Cl3—Cd1i | −96.13 (3) |
C1—C2—N2—C5 | 106.3 (3) | Cl1ii—Cd2—Cl3—Cd1i | 95.29 (7) |
C1—C2—N2—C3 | −70.3 (3) | Cl4—Cd2—Cl3—Cd1i | 4.490 (17) |
O1W—Cd1—Cl1—Cd2ii | −75.96 (5) | Cl2—Cd2—Cl3—Cd1i | 176.764 (15) |
Cl4i—Cd1—Cl1—Cd2ii | −170.68 (2) | Cl3i—Cd2—Cl3—Cd1i | 95.65 (3) |
Cl2—Cd1—Cl1—Cd2ii | 91.13 (3) | Cl5—Cd2—Cl3—Cd2i | 168.22 (2) |
Cl2ii—Cd1—Cl1—Cd2ii | 3.828 (18) | Cl1ii—Cd2—Cl3—Cd2i | −0.36 (8) |
O1W—Cd1—Cl2—Cd1ii | 10.7 (2) | Cl4—Cd2—Cl3—Cd2i | −91.16 (3) |
Cl4i—Cd1—Cl2—Cd1ii | 174.183 (18) | Cl2—Cd2—Cl3—Cd2i | 81.11 (3) |
Cl1—Cd1—Cl2—Cd1ii | −88.70 (3) | Cl3i—Cd2—Cl3—Cd2i | 0.0 |
Cl2ii—Cd1—Cl2—Cd1ii | 0.0 | Cl5—Cd2—Cl4—Cd1i | 93.13 (3) |
Cl3i—Cd1—Cl2—Cd1ii | 87.51 (3) | Cl1ii—Cd2—Cl4—Cd1i | −170.82 (2) |
O1W—Cd1—Cl2—Cd2 | −78.2 (2) | Cl3—Cd2—Cl4—Cd1i | −4.846 (18) |
Cl4i—Cd1—Cl2—Cd2 | 85.28 (3) | Cl3i—Cd2—Cl4—Cd1i | −83.64 (3) |
Cl1—Cd1—Cl2—Cd2 | −177.604 (17) |
Symmetry codes: (i) −x−2, −y+2, −z; (ii) −x−1, −y+2, −z. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O2iii | 0.83 | 1.84 | 2.673 (3) | 176 |
O1W—H1WA···Cl5ii | 0.85 | 2.54 | 3.375 (2) | 165 |
O1W—H1WB···Cl5iv | 0.84 | 2.40 | 3.171 (2) | 152 |
Symmetry codes: (ii) −x−1, −y+2, −z; (iii) −x−2, −y+2, −z+1; (iv) x, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | (C6H9N2O2)[Cd2Cl5(H2O)] |
Mr | 561.24 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 296 |
a, b, c (Å) | 7.580 (2), 10.339 (3), 10.371 (3) |
α, β, γ (°) | 74.593 (15), 81.568 (17), 83.781 (16) |
V (Å3) | 773.0 (4) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 3.61 |
Crystal size (mm) | 0.56 × 0.20 × 0.10 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.424, 0.697 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9462, 3446, 3191 |
Rint | 0.022 |
(sin θ/λ)max (Å−1) | 0.656 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.021, 0.056, 1.01 |
No. of reflections | 3446 |
No. of parameters | 163 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.52, −0.90 |
Computer programs: SMART (Bruker, 2004), SAINT (Bruker, 2004), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 2002), SHELXL97.
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O2i | 0.83 | 1.84 | 2.673 (3) | 176.1 |
O1W—H1WA···Cl5ii | 0.85 | 2.54 | 3.375 (2) | 165.4 |
O1W—H1WB···Cl5iii | 0.84 | 2.40 | 3.171 (2) | 152.1 |
Symmetry codes: (i) −x−2, −y+2, −z+1; (ii) −x−1, −y+2, −z; (iii) x, y+1, z. |
In recent years, there has been an increasing interest in the coordination chemistry of cadmium due to the increased recognition of it's role in biological organisms and molecular-based materials (Jian et al., 2006). Here, we report a novel one-dimensional Cd string complex (I), which contains one [Cd2Cl5(H2O)]- anion and one 1-methyl-3-carboxymethylimidazole cation in the asymmetric unit, (Fig.1).
The inorganic chain is formed by two paralleled chains of corner-sharing [Cd2Cl2] quadrangular, which are displaced by half distance of Cd1—Cd2 and connected by tridentate bridging chlorine atoms. In the crystal structure, two independent cadmium atoms are present, which are connected by a bidentate and a tridentate bridging chlorine atom. The six-coordination is completed on the Cd(1) atom by a tridentate bridging chlorine atom and a coordinated water molecule, while on the Cd(2) atom by a tridentate bridging and a terminal chlorine atom. In each one of paralled chains, the terminal atoms (chlorine atom and water molecule) are in cis-position to each other, but in trans-position to the terminal atoms in the other paralled chain.
Each Cd atom shows a distorted octahedral geometry, gives rise to a polymeric linear chain of edge-sharing octahedra running along the a axis. Cd—C1 distances vary according to the different bonding mode of the C1 atoms; their values normally increasing in the order terminal < dibridged < tribridged, which are in agreement with the compound repoted by Corradi (Corradi et al., 1993).
Imidazole cations form one-dimensional chains next to the inorganic chain via π-π stacking interactions. Furthermore, there are O–H···Cl and O–H···O intermolecule hydrogen bond involving coordinated water O1w atom and terminate Cl atom, as well as carboxyl O1 atom and carboxyl O2 atom (see table), which stabilize the three-dimensional network.