Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807022416/at2287sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807022416/at2287Isup2.hkl |
CCDC reference: 650670
Key indicators
- Single-crystal X-ray study
- T = 292 K
- Mean (C-C) = 0.008 Å
- R factor = 0.054
- wR factor = 0.127
- Data-to-parameter ratio = 18.9
checkCIF/PLATON results
No syntax errors found
Alert level B PLAT222_ALERT_3_B Large Non-Solvent H Ueq(max)/Ueq(min) ... 4.20 Ratio PLAT241_ALERT_2_B Check High Ueq as Compared to Neighbors for O1 PLAT241_ALERT_2_B Check High Ueq as Compared to Neighbors for C19 PLAT242_ALERT_2_B Check Low Ueq as Compared to Neighbors for C18 PLAT242_ALERT_2_B Check Low Ueq as Compared to Neighbors for C30
Alert level C PLAT220_ALERT_2_C Large Non-Solvent C Ueq(max)/Ueq(min) ... 3.39 Ratio PLAT220_ALERT_2_C Large Non-Solvent C Ueq(max)/Ueq(min) ... 2.88 Ratio PLAT222_ALERT_3_C Large Non-Solvent H Ueq(max)/Ueq(min) ... 3.49 Ratio PLAT241_ALERT_2_C Check High Ueq as Compared to Neighbors for O2 PLAT241_ALERT_2_C Check High Ueq as Compared to Neighbors for C20 PLAT241_ALERT_2_C Check High Ueq as Compared to Neighbors for C22 PLAT241_ALERT_2_C Check High Ueq as Compared to Neighbors for O5 PLAT241_ALERT_2_C Check High Ueq as Compared to Neighbors for O6 PLAT241_ALERT_2_C Check High Ueq as Compared to Neighbors for C3 PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for N5 PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C23 PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C25 PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C7 PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........ 8
Alert level G PLAT794_ALERT_5_G Check Predicted Bond Valency for Cd1 (2) 2.03 PLAT794_ALERT_5_G Check Predicted Bond Valency for Cd2 (2) 2.05 PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints ....... 24
0 ALERT level A = In general: serious problem 5 ALERT level B = Potentially serious problem 14 ALERT level C = Check and explain 3 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 16 ALERT type 2 Indicator that the structure model may be wrong or deficient 3 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 2 ALERT type 5 Informative message, check
A mixture of CdCl2.2H2O (0.5 mmol), 1,4-chdc acid (0.5 mmol), mi (0.5 mmol), and H2O (500 mmol) was adjusted to pH = 7 by addition of aqueous NaOH solution, and heated at 453 K for 6 days. After the mixture was slowly cooled to room temperature, colourless crystals of (I) were yielded (37% yield).
All H atoms on C and N atoms were positioned geometrically (N—H = 0.86 Å and C—H = 0.93 Å) and refined as riding, with Uiso(H) =1.2Ueq(carrier). The water H-atoms were located in a difference Fourier map, and were refined with distance restraints of O—H = 0.85 Å; their temperature factors were tied to those of parent atoms by a factor of 1.2.
Helical structures have received much attention in coordination chemistry and materials chemistry (Lehn, 1990). So far, many helical complexes have been generated by self-assembly processes (Chen & Liu, 2002). An appropriate flexible bidentate organic acid bridge could be useful in the formation of helical chains in the presence of secondary ligands, such as 2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen) (Li et al., 2002). The N atoms from the secondary ligand may occupy two coordination positions of metal ions. The rest of the coordination positions are available for other carboxylate ligands to allow the formation of a helix. We selected cyclohexane-1,4-dicarboxylic acid (1,4-chdcH2) as a bridging ligand and 2-methyl-1H-imidazole (mi) as a secondary ligand, generating a new helical chain coordination polymer, [Cd(1,4-chdc)(mi)2].2H2O, (I), which is reported here.
In compound (I), the asymmetric unit contains two crystallographically nonequivalent CdII atoms (Cd1 and Cd2), two 1,4-chdc anions, four mi ligands, and four free water molecules (Fig. 1). Each CdII atom is six-coordinated by two N atoms from two mi molecules, and four O atoms from two 1,4-chdc ligands in a distorted octahedral environment (Fig. 1). The Cd—O distances range from 2.279 (5) to 2.457 (4) Å, and the Cd—N distances vary from 2.235 (5) to 2.269 (4) Å (Table 1). As shown in Fig. 2, each 1,4-chdc moiety acts as a bis-chelating ligand that binds two CdII atoms, forming two unique helical chains. These chains are decorated with mi ligands alternately at two sides. Furthermore, the O—H···O and N—H···O hydrogen bonds (Table 2) link the chains together, forming a three-dimensional supramolecular structure of (I). There are weak π—π interactions between 2-methyl- 1H-imidazole ligands in neighboring chains at (x, y, z) and (-x, -y, 2 - z), with the interplanar distance of 3.62 (2) Å.
Two related helical coordination polymers with mixed ligands, [Co2(phen)2(1,4-chdc)2(H2O)2]n and [Ni2(phen)2(1,4-chdc)2(H2O)2]n, have been prepared under hydrothermal conditions. The most attractive structural feature of the two isomorphic compounds is that they both exhibit an infinite helical chainlike structure with 21 helices. Moreover, the adjacent chains are linked via hydrogen bonds and π-π interactions into three-dimensional supramolecular structures (Qi et al., 2003).
For related literature, see: Chen & Liu (2002); Lehn (1990); Li et al. (2002).
Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO; data reduction: PROCESS-AUTO; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL-Plus (Sheldrick, 1990); software used to prepare material for publication: SHELXL97.
[Cd(C8H10O2)(C4H6N2)2]·2H2O | F(000) = 3936 |
Mr = 482.81 | Dx = 1.496 Mg m−3 |
Orthorhombic, Pbca | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2ab | Cell parameters from 51297 reflections |
a = 17.593 (4) Å | θ = 3.2–27.5° |
b = 16.005 (3) Å | µ = 1.06 mm−1 |
c = 30.446 (6) Å | T = 292 K |
V = 8573 (3) Å3 | Block, colourless |
Z = 16 | 0.33 × 0.31 × 0.28 mm |
Rigaku R-AXIS RAPID diffractometer | 9751 independent reflections |
Radiation source: rotating anode | 6833 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.074 |
Detector resolution: 10.0 pixels mm-1 | θmax = 27.5°, θmin = 3.2° |
ω scans | h = −22→22 |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | k = −20→20 |
Tmin = 0.698, Tmax = 0.742 | l = −39→38 |
71497 measured reflections |
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)] = 0.054 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.127 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.01 | w = 1/[σ2(Fo2) + (0.0421P)2 + 26.2686P] where P = (Fo2 + 2Fc2)/3 |
9751 reflections | (Δ/σ)max = 0.002 |
515 parameters | Δρmax = 1.41 e Å−3 |
24 restraints | Δρmin = −1.01 e Å−3 |
[Cd(C8H10O2)(C4H6N2)2]·2H2O | V = 8573 (3) Å3 |
Mr = 482.81 | Z = 16 |
Orthorhombic, Pbca | Mo Kα radiation |
a = 17.593 (4) Å | µ = 1.06 mm−1 |
b = 16.005 (3) Å | T = 292 K |
c = 30.446 (6) Å | 0.33 × 0.31 × 0.28 mm |
Rigaku R-AXIS RAPID diffractometer | 9751 independent reflections |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | 6833 reflections with I > 2σ(I) |
Tmin = 0.698, Tmax = 0.742 | Rint = 0.074 |
71497 measured reflections |
R[F2 > 2σ(F2)] = 0.054 | 24 restraints |
wR(F2) = 0.127 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.01 | w = 1/[σ2(Fo2) + (0.0421P)2 + 26.2686P] where P = (Fo2 + 2Fc2)/3 |
9751 reflections | Δρmax = 1.41 e Å−3 |
515 parameters | Δρmin = −1.01 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 | ||
C1 | 0.3487 (4) | 0.0299 (4) | 0.8365 (2) | 0.0655 (16) | |
C2 | 0.3969 (4) | 0.0552 (5) | 0.8728 (2) | 0.084 (2) | |
H2A | 0.4082 | 0.0075 | 0.8908 | 0.125* | |
H2B | 0.3710 | 0.0966 | 0.8900 | 0.125* | |
H2C | 0.4433 | 0.0783 | 0.8615 | 0.125* | |
C3 | 0.2583 (6) | −0.0328 (6) | 0.8009 (3) | 0.117 (4) | |
H3 | 0.2163 | −0.0658 | 0.7943 | 0.140* | |
C4 | 0.2962 (5) | 0.0120 (5) | 0.7727 (2) | 0.093 (3) | |
H4 | 0.2862 | 0.0165 | 0.7428 | 0.111* | |
C5 | 0.4929 (5) | −0.0180 (4) | 0.6884 (2) | 0.086 (2) | |
H5 | 0.4682 | 0.0088 | 0.6654 | 0.104* | |
C6 | 0.5290 (5) | −0.0929 (5) | 0.6857 (2) | 0.091 (3) | |
H6 | 0.5335 | −0.1268 | 0.6610 | 0.109* | |
C7 | 0.5378 (3) | −0.0443 (4) | 0.75212 (19) | 0.0567 (14) | |
C8 | 0.5594 (5) | −0.0398 (6) | 0.7991 (2) | 0.114 (3) | |
H8A | 0.5626 | −0.0953 | 0.8110 | 0.171* | |
H8B | 0.5218 | −0.0085 | 0.8150 | 0.171* | |
H8C | 0.6079 | −0.0128 | 0.8018 | 0.171* | |
C9 | 0.3491 (3) | 0.2185 (3) | 0.70464 (16) | 0.0418 (11) | |
C10 | 0.3014 (3) | 0.2702 (3) | 0.67294 (15) | 0.0425 (11) | |
H10 | 0.3373 | 0.3010 | 0.6544 | 0.051* | |
C11 | 0.2531 (3) | 0.3359 (3) | 0.69652 (18) | 0.0471 (12) | |
H11A | 0.2352 | 0.3767 | 0.6753 | 0.057* | |
H11B | 0.2842 | 0.3649 | 0.7179 | 0.057* | |
C12 | 0.1844 (3) | 0.2963 (3) | 0.71987 (16) | 0.0464 (12) | |
H12A | 0.2022 | 0.2592 | 0.7429 | 0.056* | |
H12B | 0.1541 | 0.3399 | 0.7334 | 0.056* | |
C13 | 0.1358 (3) | 0.2479 (3) | 0.68804 (15) | 0.0407 (11) | |
H13 | 0.1187 | 0.2866 | 0.6652 | 0.049* | |
C14 | 0.1845 (3) | 0.1795 (3) | 0.66569 (16) | 0.0451 (12) | |
H14A | 0.2019 | 0.1400 | 0.6876 | 0.054* | |
H14B | 0.1536 | 0.1493 | 0.6446 | 0.054* | |
C15 | 0.2530 (3) | 0.2179 (4) | 0.64228 (15) | 0.0500 (13) | |
H15A | 0.2839 | 0.1736 | 0.6299 | 0.060* | |
H15B | 0.2353 | 0.2527 | 0.6183 | 0.060* | |
C16 | 0.0660 (3) | 0.2092 (3) | 0.70850 (15) | 0.0421 (11) | |
C17 | 0.0291 (5) | 0.2609 (8) | 0.8744 (3) | 0.140 (4) | |
H17A | 0.0182 | 0.3013 | 0.8519 | 0.210* | |
H17B | 0.0254 | 0.2868 | 0.9027 | 0.210* | |
H17C | −0.0067 | 0.2158 | 0.8725 | 0.210* | |
C18 | 0.1073 (4) | 0.2279 (4) | 0.86811 (18) | 0.0582 (15) | |
C19 | 0.2189 (5) | 0.1846 (8) | 0.8780 (2) | 0.132 (4) | |
H19 | 0.2637 | 0.1674 | 0.8915 | 0.158* | |
C20 | 0.2070 (6) | 0.1864 (7) | 0.8342 (3) | 0.125 (3) | |
H20 | 0.2414 | 0.1722 | 0.8122 | 0.150* | |
C21 | −0.0350 (4) | 0.1632 (5) | 0.9842 (3) | 0.088 (2) | |
H21 | −0.0451 | 0.2114 | 1.0002 | 0.106* | |
C22 | −0.0868 (5) | 0.1091 (6) | 0.9702 (3) | 0.117 (3) | |
H22 | −0.1390 | 0.1120 | 0.9746 | 0.140* | |
C23 | 0.0253 (4) | 0.0665 (4) | 0.9494 (2) | 0.0644 (16) | |
C24 | 0.0853 (5) | 0.0148 (5) | 0.9297 (3) | 0.116 (3) | |
H24A | 0.1299 | 0.0170 | 0.9478 | 0.174* | |
H24B | 0.0972 | 0.0354 | 0.9009 | 0.174* | |
H24C | 0.0680 | −0.0420 | 0.9276 | 0.174* | |
C25 | 0.2703 (3) | 0.1530 (3) | 1.01604 (16) | 0.0446 (12) | |
C26 | 0.3384 (3) | 0.1297 (3) | 1.04391 (17) | 0.0487 (12) | |
H26 | 0.3531 | 0.1802 | 1.0601 | 0.058* | |
C27 | 0.4074 (3) | 0.1047 (3) | 1.01558 (18) | 0.0489 (13) | |
H27A | 0.4141 | 0.1454 | 0.9923 | 0.059* | |
H27B | 0.4529 | 0.1052 | 1.0336 | 0.059* | |
C28 | 0.3971 (3) | 0.0188 (3) | 0.99572 (16) | 0.0440 (11) | |
H28A | 0.4415 | 0.0048 | 0.9784 | 0.053* | |
H28B | 0.3534 | 0.0193 | 0.9763 | 0.053* | |
C29 | 0.3855 (3) | −0.0475 (3) | 1.03110 (15) | 0.0414 (11) | |
H29 | 0.4294 | −0.0461 | 1.0508 | 0.050* | |
C30 | 0.3793 (3) | −0.1346 (3) | 1.01204 (17) | 0.0466 (12) | |
C32 | 0.3221 (4) | 0.0625 (4) | 1.07818 (16) | 0.0561 (15) | |
H32A | 0.3627 | 0.0619 | 1.0997 | 0.067* | |
H32B | 0.2752 | 0.0760 | 1.0934 | 0.067* | |
C33 | 0.3150 (3) | −0.0239 (3) | 1.05761 (16) | 0.0500 (13) | |
H33A | 0.2708 | −0.0250 | 1.0385 | 0.060* | |
H33B | 0.3072 | −0.0649 | 1.0806 | 0.060* | |
N1 | 0.3556 (3) | 0.0527 (3) | 0.79580 (16) | 0.0665 (14) | |
N2 | 0.2897 (3) | −0.0240 (4) | 0.84165 (18) | 0.0800 (17) | |
H2 | 0.2751 | −0.0477 | 0.8656 | 0.096* | |
N3 | 0.4986 (3) | 0.0114 (3) | 0.73007 (15) | 0.0572 (12) | |
N4 | 0.5567 (3) | −0.1078 (3) | 0.72553 (18) | 0.0638 (13) | |
H4A | 0.5826 | −0.1511 | 0.7331 | 0.077* | |
N5 | 0.1569 (3) | 0.2111 (3) | 0.89909 (14) | 0.0599 (13) | |
N6 | 0.1345 (3) | 0.2130 (4) | 0.82889 (16) | 0.0862 (19) | |
H6A | 0.1109 | 0.2191 | 0.8044 | 0.103* | |
N7 | 0.0366 (3) | 0.1368 (3) | 0.97121 (16) | 0.0603 (12) | |
N8 | −0.0480 (4) | 0.0483 (4) | 0.9479 (2) | 0.0862 (19) | |
H8 | −0.0679 | 0.0056 | 0.9352 | 0.103* | |
O1 | 0.2783 (2) | 0.1910 (3) | 0.98117 (14) | 0.0797 (14) | |
O2 | 0.2054 (2) | 0.1357 (3) | 1.02861 (14) | 0.0738 (13) | |
O1W | 0.1019 (3) | 0.0996 (3) | 1.09298 (15) | 0.0737 (13) | |
HW11 | 0.139 (2) | 0.113 (4) | 1.0753 (18) | 0.088* | |
HW12 | 0.067 (3) | 0.138 (3) | 1.090 (2) | 0.088* | |
O3 | 0.3518 (4) | −0.1455 (3) | 0.97550 (18) | 0.112 (2) | |
O2W | 0.4907 (3) | −0.2497 (3) | 1.09893 (13) | 0.0690 (12) | |
HW21 | 0.464 (3) | −0.218 (3) | 1.0825 (15) | 0.083* | |
HW22 | 0.491 (4) | −0.232 (4) | 1.1251 (8) | 0.083* | |
O4 | 0.4037 (3) | −0.1952 (3) | 1.03138 (15) | 0.0824 (15) | |
O3W | 0.2434 (3) | −0.0813 (4) | 0.92112 (18) | 0.0933 (16) | |
HW31 | 0.209 (3) | −0.120 (4) | 0.924 (2) | 0.112* | |
HW32 | 0.277 (3) | −0.090 (5) | 0.941 (2) | 0.112* | |
O5 | 0.3690 (2) | 0.2477 (2) | 0.74102 (13) | 0.0610 (11) | |
O4W | 0.3630 (3) | 0.2924 (4) | 0.9246 (2) | 0.1069 (19) | |
HW41 | 0.344 (4) | 0.252 (4) | 0.940 (3) | 0.128* | |
HW42 | 0.407 (3) | 0.275 (5) | 0.915 (3) | 0.128* | |
O6 | 0.3704 (3) | 0.1473 (3) | 0.69354 (13) | 0.0691 (12) | |
O7 | 0.0579 (2) | 0.2059 (3) | 0.74928 (11) | 0.0602 (11) | |
O8 | 0.0155 (2) | 0.1791 (3) | 0.68348 (11) | 0.0533 (9) | |
Cd1 | 0.44158 (2) | 0.12656 (2) | 0.758212 (12) | 0.04416 (11) | |
Cd2 | 0.14412 (2) | 0.21222 (2) | 0.973230 (11) | 0.04324 (11) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.060 (4) | 0.071 (4) | 0.065 (4) | −0.002 (3) | 0.006 (3) | 0.001 (3) |
C2 | 0.068 (5) | 0.123 (6) | 0.060 (4) | −0.019 (4) | 0.000 (3) | 0.019 (4) |
C3 | 0.127 (8) | 0.136 (8) | 0.087 (5) | −0.081 (7) | 0.001 (5) | −0.013 (5) |
C4 | 0.113 (7) | 0.100 (6) | 0.065 (4) | −0.048 (5) | 0.006 (4) | −0.005 (4) |
C5 | 0.123 (7) | 0.066 (4) | 0.070 (4) | 0.030 (4) | −0.038 (4) | −0.010 (3) |
C6 | 0.116 (7) | 0.074 (5) | 0.081 (5) | 0.032 (5) | −0.031 (5) | −0.030 (4) |
C7 | 0.048 (3) | 0.057 (3) | 0.064 (3) | 0.014 (3) | 0.005 (3) | 0.008 (3) |
C8 | 0.133 (8) | 0.131 (8) | 0.077 (5) | 0.072 (6) | −0.019 (5) | 0.013 (5) |
C9 | 0.031 (2) | 0.051 (3) | 0.044 (3) | −0.007 (2) | −0.001 (2) | 0.006 (2) |
C10 | 0.029 (2) | 0.058 (3) | 0.040 (2) | −0.002 (2) | 0.0027 (19) | 0.010 (2) |
C11 | 0.036 (3) | 0.045 (3) | 0.061 (3) | 0.000 (2) | 0.002 (2) | 0.009 (2) |
C12 | 0.038 (3) | 0.055 (3) | 0.046 (3) | −0.006 (2) | 0.006 (2) | −0.008 (2) |
C13 | 0.031 (3) | 0.053 (3) | 0.038 (2) | 0.001 (2) | −0.0010 (19) | 0.007 (2) |
C14 | 0.032 (3) | 0.061 (3) | 0.042 (3) | −0.005 (2) | −0.001 (2) | −0.008 (2) |
C15 | 0.035 (3) | 0.078 (4) | 0.036 (2) | 0.002 (3) | 0.000 (2) | −0.002 (3) |
C16 | 0.032 (3) | 0.055 (3) | 0.039 (2) | 0.003 (2) | 0.000 (2) | 0.003 (2) |
C17 | 0.096 (7) | 0.233 (13) | 0.091 (6) | 0.073 (8) | −0.003 (5) | 0.037 (7) |
C18 | 0.059 (4) | 0.068 (4) | 0.047 (3) | 0.002 (3) | −0.006 (3) | 0.003 (3) |
C19 | 0.084 (6) | 0.256 (13) | 0.054 (4) | 0.081 (7) | −0.015 (4) | −0.039 (6) |
C20 | 0.114 (6) | 0.188 (8) | 0.072 (5) | 0.056 (6) | 0.000 (4) | −0.028 (5) |
C21 | 0.077 (5) | 0.077 (5) | 0.110 (6) | −0.019 (4) | 0.022 (4) | −0.024 (4) |
C22 | 0.066 (5) | 0.133 (8) | 0.152 (8) | −0.030 (5) | 0.025 (5) | −0.053 (7) |
C23 | 0.084 (5) | 0.046 (3) | 0.064 (4) | −0.004 (3) | −0.010 (3) | 0.001 (3) |
C24 | 0.121 (8) | 0.065 (5) | 0.163 (9) | 0.012 (5) | 0.004 (7) | −0.037 (5) |
C25 | 0.052 (3) | 0.037 (3) | 0.044 (3) | 0.005 (2) | −0.003 (2) | −0.006 (2) |
C26 | 0.056 (3) | 0.042 (3) | 0.048 (3) | 0.001 (3) | −0.011 (2) | −0.009 (2) |
C27 | 0.038 (3) | 0.041 (3) | 0.068 (3) | −0.001 (2) | −0.008 (2) | 0.001 (2) |
C28 | 0.036 (3) | 0.049 (3) | 0.048 (3) | 0.001 (2) | 0.006 (2) | −0.003 (2) |
C29 | 0.041 (3) | 0.042 (3) | 0.041 (2) | 0.006 (2) | −0.009 (2) | −0.003 (2) |
C30 | 0.048 (3) | 0.048 (3) | 0.044 (3) | 0.000 (3) | −0.006 (2) | −0.003 (2) |
C32 | 0.071 (4) | 0.062 (4) | 0.035 (3) | 0.018 (3) | −0.005 (2) | −0.006 (2) |
C33 | 0.060 (4) | 0.051 (3) | 0.039 (3) | 0.004 (3) | 0.004 (2) | 0.011 (2) |
N1 | 0.072 (4) | 0.065 (3) | 0.062 (3) | −0.016 (3) | −0.002 (3) | 0.003 (3) |
N2 | 0.087 (4) | 0.088 (4) | 0.065 (3) | −0.039 (3) | 0.003 (3) | 0.010 (3) |
N3 | 0.060 (3) | 0.052 (3) | 0.059 (3) | 0.007 (2) | −0.007 (2) | 0.002 (2) |
N4 | 0.064 (3) | 0.046 (3) | 0.081 (3) | 0.012 (2) | −0.009 (3) | 0.000 (2) |
N5 | 0.053 (3) | 0.083 (4) | 0.043 (2) | 0.003 (3) | −0.007 (2) | −0.014 (2) |
N6 | 0.077 (4) | 0.137 (6) | 0.044 (3) | 0.022 (4) | −0.017 (3) | −0.008 (3) |
N7 | 0.067 (3) | 0.052 (3) | 0.061 (3) | −0.010 (2) | −0.006 (2) | −0.002 (2) |
N8 | 0.088 (5) | 0.077 (4) | 0.093 (4) | −0.040 (4) | −0.017 (4) | −0.006 (3) |
O1 | 0.056 (3) | 0.111 (4) | 0.072 (3) | 0.000 (3) | −0.006 (2) | 0.040 (3) |
O2 | 0.049 (3) | 0.101 (4) | 0.071 (3) | 0.014 (2) | 0.007 (2) | 0.028 (2) |
O1W | 0.081 (3) | 0.073 (3) | 0.066 (3) | −0.024 (3) | 0.014 (2) | −0.004 (2) |
O3 | 0.175 (5) | 0.058 (3) | 0.102 (4) | 0.009 (3) | −0.076 (4) | −0.016 (3) |
O2W | 0.069 (3) | 0.088 (3) | 0.049 (2) | 0.014 (3) | 0.001 (2) | −0.004 (2) |
O4 | 0.124 (4) | 0.045 (2) | 0.078 (3) | 0.015 (3) | −0.038 (3) | −0.005 (2) |
O3W | 0.074 (4) | 0.115 (4) | 0.091 (4) | −0.005 (3) | −0.004 (3) | 0.042 (3) |
O5 | 0.071 (3) | 0.055 (2) | 0.058 (2) | −0.012 (2) | −0.031 (2) | 0.0038 (18) |
O4W | 0.072 (4) | 0.112 (5) | 0.136 (5) | 0.011 (3) | 0.014 (3) | 0.041 (4) |
O6 | 0.078 (3) | 0.067 (3) | 0.062 (2) | 0.030 (2) | −0.017 (2) | −0.012 (2) |
O7 | 0.045 (2) | 0.099 (3) | 0.0366 (18) | −0.019 (2) | 0.0004 (16) | 0.0044 (19) |
O8 | 0.040 (2) | 0.080 (3) | 0.0404 (18) | −0.0171 (19) | −0.0017 (15) | −0.0007 (18) |
Cd1 | 0.03687 (19) | 0.0486 (2) | 0.0470 (2) | 0.00164 (17) | −0.01030 (16) | 0.00212 (17) |
Cd2 | 0.0455 (2) | 0.0431 (2) | 0.04110 (19) | 0.00382 (17) | −0.00389 (16) | −0.00270 (16) |
C1—N1 | 1.298 (8) | C21—N7 | 1.386 (9) |
C1—N2 | 1.360 (8) | C21—H21 | 0.9300 |
C1—C2 | 1.449 (9) | C22—N8 | 1.368 (10) |
C2—H2A | 0.9600 | C22—H22 | 0.9300 |
C2—H2B | 0.9600 | C23—N8 | 1.323 (8) |
C2—H2C | 0.9600 | C23—N7 | 1.322 (7) |
C3—C4 | 1.303 (10) | C23—C24 | 1.468 (10) |
C3—N2 | 1.364 (9) | C24—H24A | 0.9600 |
C3—H3 | 0.9300 | C24—H24B | 0.9600 |
C4—N1 | 1.416 (9) | C24—H24C | 0.9600 |
C4—H4 | 0.9300 | C25—O1 | 1.232 (6) |
C5—C6 | 1.359 (9) | C25—O2 | 1.234 (7) |
C5—N3 | 1.356 (7) | C25—C26 | 1.516 (7) |
C5—H5 | 0.9300 | C26—C32 | 1.527 (8) |
C6—N4 | 1.329 (8) | C26—C27 | 1.542 (8) |
C6—H6 | 0.9300 | C26—H26 | 0.9800 |
C7—N3 | 1.313 (7) | C27—C28 | 1.513 (7) |
C7—N4 | 1.342 (7) | C27—H27A | 0.9700 |
C7—C8 | 1.482 (9) | C27—H27B | 0.9700 |
C8—H8A | 0.9600 | C28—C29 | 1.525 (7) |
C8—H8B | 0.9600 | C28—H28A | 0.9700 |
C8—H8C | 0.9600 | C28—H28B | 0.9700 |
C9—O6 | 1.246 (6) | C29—C30 | 1.515 (7) |
C9—O5 | 1.252 (6) | C29—C33 | 1.527 (7) |
C9—C10 | 1.523 (7) | C29—H29 | 0.9800 |
C10—C15 | 1.516 (7) | C30—O4 | 1.214 (6) |
C10—C11 | 1.531 (7) | C30—O3 | 1.226 (6) |
C10—H10 | 0.9800 | C32—C33 | 1.523 (8) |
C11—C12 | 1.538 (7) | C32—H32A | 0.9700 |
C11—H11A | 0.9700 | C32—H32B | 0.9700 |
C11—H11B | 0.9700 | C33—H33A | 0.9700 |
C12—C13 | 1.508 (7) | C33—H33B | 0.9700 |
C12—H12A | 0.9700 | Cd1—N1 | 2.235 (5) |
C12—H12B | 0.9700 | N2—H2 | 0.8600 |
C13—C16 | 1.509 (7) | Cd1—N3 | 2.266 (5) |
C13—C14 | 1.547 (7) | N4—H4A | 0.8600 |
C13—H13 | 0.9800 | Cd2—N5 | 2.269 (4) |
C14—C15 | 1.530 (7) | N6—H6A | 0.8600 |
C14—H14A | 0.9700 | Cd2—N7 | 2.244 (5) |
C14—H14B | 0.9700 | N8—H8 | 0.8600 |
C15—H15A | 0.9700 | Cd2—O1 | 2.397 (4) |
C15—H15B | 0.9700 | Cd2—O2 | 2.347 (4) |
C16—O7 | 1.251 (6) | O1W—HW11 | 0.87 (5) |
C16—O8 | 1.266 (6) | O1W—HW12 | 0.87 (5) |
C17—C18 | 1.485 (10) | O2W—HW21 | 0.85 (5) |
C17—H17A | 0.9600 | O2W—HW22 | 0.844 (19) |
C17—H17B | 0.9600 | O3W—HW31 | 0.87 (6) |
C17—H17C | 0.9600 | O3W—HW32 | 0.86 (6) |
C18—N6 | 1.308 (7) | O4W—HW41 | 0.87 (7) |
C18—N5 | 1.313 (7) | O4W—HW42 | 0.87 (6) |
C19—N5 | 1.335 (8) | Cd1—O5 | 2.380 (4) |
C19—C20 | 1.352 (10) | Cd1—O6 | 2.357 (4) |
C19—H19 | 0.9300 | Cd1—O8i | 2.355 (3) |
C20—N6 | 1.354 (10) | Cd1—O7i | 2.419 (4) |
C20—H20 | 0.9300 | Cd2—O3ii | 2.279 (5) |
C21—C22 | 1.327 (10) | Cd2—O4ii | 2.457 (4) |
N1—C1—N2 | 111.0 (6) | C25—C26—C32 | 114.0 (5) |
N1—C1—C2 | 126.5 (6) | C25—C26—C27 | 111.9 (4) |
N2—C1—C2 | 122.5 (6) | C32—C26—C27 | 110.3 (4) |
C1—C2—H2A | 109.5 | C25—C26—H26 | 106.7 |
C1—C2—H2B | 109.5 | C32—C26—H26 | 106.7 |
H2A—C2—H2B | 109.5 | C27—C26—H26 | 106.7 |
C1—C2—H2C | 109.5 | C28—C27—C26 | 111.4 (4) |
H2A—C2—H2C | 109.5 | C28—C27—H27A | 109.3 |
H2B—C2—H2C | 109.5 | C26—C27—H27A | 109.3 |
C4—C3—N2 | 109.6 (7) | C28—C27—H27B | 109.3 |
C4—C3—H3 | 125.2 | C26—C27—H27B | 109.3 |
N2—C3—H3 | 125.2 | H27A—C27—H27B | 108.0 |
C3—C4—N1 | 107.7 (7) | C27—C28—C29 | 111.5 (4) |
C3—C4—H4 | 126.1 | C27—C28—H28A | 109.3 |
N1—C4—H4 | 126.1 | C29—C28—H28A | 109.3 |
C6—C5—N3 | 109.3 (6) | C27—C28—H28B | 109.3 |
C6—C5—H5 | 125.4 | C29—C28—H28B | 109.3 |
N3—C5—H5 | 125.4 | H28A—C28—H28B | 108.0 |
N4—C6—C5 | 105.9 (6) | C30—C29—C28 | 112.3 (4) |
N4—C6—H6 | 127.1 | C30—C29—C33 | 111.9 (4) |
C5—C6—H6 | 127.1 | C28—C29—C33 | 108.1 (4) |
N3—C7—N4 | 109.7 (5) | C30—C29—H29 | 108.2 |
N3—C7—C8 | 126.6 (6) | C28—C29—H29 | 108.2 |
N4—C7—C8 | 123.7 (6) | C33—C29—H29 | 108.2 |
C7—C8—H8A | 109.5 | O4—C30—O3 | 117.8 (5) |
C7—C8—H8B | 109.5 | O4—C30—C29 | 121.7 (5) |
H8A—C8—H8B | 109.5 | O3—C30—C29 | 120.5 (5) |
C7—C8—H8C | 109.5 | O4—C30—Cd2iii | 63.2 (3) |
H8A—C8—H8C | 109.5 | O3—C30—Cd2iii | 54.8 (3) |
H8B—C8—H8C | 109.5 | C29—C30—Cd2iii | 174.5 (4) |
O6—C9—O5 | 119.8 (5) | C33—C32—C26 | 112.0 (4) |
O6—C9—C10 | 119.4 (4) | C33—C32—H32A | 109.2 |
O5—C9—C10 | 120.8 (5) | C26—C32—H32A | 109.2 |
C15—C10—C9 | 113.5 (4) | C33—C32—H32B | 109.2 |
C15—C10—C11 | 110.8 (4) | C26—C32—H32B | 109.2 |
C9—C10—C11 | 112.4 (4) | H32A—C32—H32B | 107.9 |
C15—C10—H10 | 106.5 | C32—C33—C29 | 112.0 (5) |
C9—C10—H10 | 106.5 | C32—C33—H33A | 109.2 |
C11—C10—H10 | 106.5 | C29—C33—H33A | 109.2 |
C10—C11—C12 | 111.8 (4) | C32—C33—H33B | 109.2 |
C10—C11—H11A | 109.3 | C29—C33—H33B | 109.2 |
C12—C11—H11A | 109.3 | H33A—C33—H33B | 107.9 |
C10—C11—H11B | 109.3 | C1—N1—C4 | 106.0 (6) |
C12—C11—H11B | 109.3 | C1—N1—Cd1 | 134.5 (4) |
H11A—C11—H11B | 107.9 | C4—N1—Cd1 | 119.2 (4) |
C13—C12—C11 | 111.1 (4) | C1—N2—C3 | 105.7 (6) |
C13—C12—H12A | 109.4 | C1—N2—H2 | 127.2 |
C11—C12—H12A | 109.4 | C3—N2—H2 | 127.2 |
C13—C12—H12B | 109.4 | C7—N3—C5 | 106.3 (5) |
C11—C12—H12B | 109.4 | C7—N3—Cd1 | 126.3 (4) |
H12A—C12—H12B | 108.0 | C5—N3—Cd1 | 127.1 (4) |
C12—C13—C16 | 114.0 (4) | C6—N4—C7 | 108.9 (5) |
C12—C13—C14 | 109.4 (4) | C6—N4—H4A | 125.6 |
C16—C13—C14 | 110.0 (4) | C7—N4—H4A | 125.6 |
C12—C13—H13 | 107.7 | C18—N5—C19 | 105.3 (5) |
C16—C13—H13 | 107.7 | C18—N5—Cd2 | 130.3 (4) |
C14—C13—H13 | 107.7 | C19—N5—Cd2 | 124.2 (4) |
C15—C14—C13 | 110.9 (4) | C18—N6—C20 | 107.1 (6) |
C15—C14—H14A | 109.5 | C18—N6—H6A | 126.4 |
C13—C14—H14A | 109.5 | C20—N6—H6A | 126.4 |
C15—C14—H14B | 109.5 | C23—N7—C21 | 105.4 (6) |
C13—C14—H14B | 109.5 | C23—N7—Cd2 | 126.7 (5) |
H14A—C14—H14B | 108.0 | C21—N7—Cd2 | 126.5 (4) |
C10—C15—C14 | 112.2 (4) | C23—N8—C22 | 108.3 (6) |
C10—C15—H15A | 109.2 | C23—N8—H8 | 125.9 |
C14—C15—H15A | 109.2 | C22—N8—H8 | 125.9 |
C10—C15—H15B | 109.2 | C25—O1—Cd2 | 92.5 (4) |
C14—C15—H15B | 109.2 | C25—O2—Cd2 | 94.9 (3) |
H15A—C15—H15B | 107.9 | HW11—O1W—HW12 | 107 (3) |
O7—C16—O8 | 120.0 (4) | C30—O3—Cd2iii | 99.1 (4) |
O7—C16—C13 | 121.4 (4) | HW21—O2W—HW22 | 111 (3) |
O8—C16—C13 | 118.6 (4) | C30—O4—Cd2iii | 90.6 (3) |
C18—C17—H17A | 109.5 | HW31—O3W—HW32 | 108 (3) |
C18—C17—H17B | 109.5 | C9—O5—Cd1 | 92.3 (3) |
H17A—C17—H17B | 109.5 | HW41—O4W—HW42 | 107 (7) |
C18—C17—H17C | 109.5 | C9—O6—Cd1 | 93.5 (3) |
H17A—C17—H17C | 109.5 | C16—O7—Cd1iv | 91.5 (3) |
H17B—C17—H17C | 109.5 | C16—O8—Cd1iv | 94.0 (3) |
N6—C18—N5 | 112.0 (6) | N1—Cd1—N3 | 93.62 (19) |
N6—C18—C17 | 121.4 (6) | N1—Cd1—O8i | 100.17 (15) |
N5—C18—C17 | 126.6 (6) | N3—Cd1—O8i | 109.32 (16) |
N5—C19—C20 | 110.0 (7) | N1—Cd1—O6 | 98.18 (18) |
N5—C19—H19 | 125.0 | N3—Cd1—O6 | 91.94 (15) |
C20—C19—H19 | 125.0 | O8i—Cd1—O6 | 150.77 (15) |
N6—C20—C19 | 105.6 (7) | N1—Cd1—O5 | 100.37 (18) |
N6—C20—H20 | 127.2 | N3—Cd1—O5 | 144.75 (15) |
C19—C20—H20 | 127.2 | O8i—Cd1—O5 | 99.87 (13) |
C22—C21—N7 | 109.5 (7) | O6—Cd1—O5 | 54.29 (13) |
C22—C21—H21 | 125.2 | N1—Cd1—O7i | 153.96 (16) |
N7—C21—H21 | 125.2 | N3—Cd1—O7i | 90.96 (17) |
C21—C22—N8 | 106.3 (7) | O8i—Cd1—O7i | 54.33 (11) |
C21—C22—H22 | 126.9 | O6—Cd1—O7i | 107.27 (15) |
N8—C22—H22 | 126.9 | O5—Cd1—O7i | 90.33 (15) |
N8—C23—N7 | 110.5 (6) | N7—Cd2—N5 | 92.99 (18) |
N8—C23—C24 | 124.3 (7) | N7—Cd2—O3ii | 124.4 (2) |
N7—C23—C24 | 125.2 (7) | N5—Cd2—O3ii | 91.99 (19) |
C23—C24—H24A | 109.5 | N7—Cd2—O2 | 97.27 (17) |
C23—C24—H24B | 109.5 | N5—Cd2—O2 | 131.71 (17) |
H24A—C24—H24B | 109.5 | O3ii—Cd2—O2 | 119.0 (2) |
C23—C24—H24C | 109.5 | N7—Cd2—O1 | 139.16 (18) |
H24A—C24—H24C | 109.5 | N5—Cd2—O1 | 90.09 (16) |
H24B—C24—H24C | 109.5 | O3ii—Cd2—O1 | 96.1 (2) |
O1—C25—O2 | 119.0 (5) | O2—Cd2—O1 | 53.20 (14) |
O1—C25—C26 | 120.9 (5) | N7—Cd2—O4ii | 93.16 (18) |
O2—C25—C26 | 120.1 (5) | N5—Cd2—O4ii | 139.08 (18) |
O1—C25—Cd2 | 60.8 (3) | O3ii—Cd2—O4ii | 52.18 (15) |
O2—C25—Cd2 | 58.5 (3) | O2—Cd2—O4ii | 87.38 (17) |
C26—C25—Cd2 | 172.4 (3) | O1—Cd2—O4ii | 110.49 (19) |
Symmetry codes: (i) x+1/2, y, −z+3/2; (ii) −x+1/2, y+1/2, z; (iii) −x+1/2, y−1/2, z; (iv) x−1/2, y, −z+3/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—HW11···O2 | 0.87 (5) | 1.88 (5) | 2.737 (6) | 169 (7) |
O2W—HW21···O4 | 0.85 (5) | 1.92 (3) | 2.708 (6) | 153 (6) |
O2W—HW22···O8v | 0.84 (2) | 1.97 (2) | 2.814 (5) | 173 (5) |
O3W—HW32···O3 | 0.86 (6) | 1.90 (4) | 2.727 (7) | 160 (8) |
O3W—HW31···O4Wiii | 0.87 (6) | 1.89 (6) | 2.758 (8) | 176 (9) |
O4W—HW41···O1 | 0.87 (7) | 1.97 (8) | 2.797 (7) | 160 (7) |
O4W—HW42···O2Wvi | 0.87 (6) | 1.90 (3) | 2.756 (7) | 170 (9) |
N2—H2···O3W | 0.86 | 1.86 | 2.712 (7) | 171 |
N4—H4A···O5vii | 0.86 | 1.99 | 2.845 (6) | 171 |
N6—H6A···O7 | 0.86 | 1.93 | 2.776 (6) | 167 |
N8—H8···O1Wviii | 0.86 | 1.98 | 2.839 (7) | 173 |
Symmetry codes: (iii) −x+1/2, y−1/2, z; (v) −x+1/2, −y, z+1/2; (vi) −x+1, −y, −z+2; (vii) −x+1, y−1/2, −z+3/2; (viii) −x, −y, −z+2. |
Experimental details
Crystal data | |
Chemical formula | [Cd(C8H10O2)(C4H6N2)2]·2H2O |
Mr | 482.81 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 292 |
a, b, c (Å) | 17.593 (4), 16.005 (3), 30.446 (6) |
V (Å3) | 8573 (3) |
Z | 16 |
Radiation type | Mo Kα |
µ (mm−1) | 1.06 |
Crystal size (mm) | 0.33 × 0.31 × 0.28 |
Data collection | |
Diffractometer | Rigaku R-AXIS RAPID |
Absorption correction | Multi-scan (ABSCOR; Higashi, 1995) |
Tmin, Tmax | 0.698, 0.742 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 71497, 9751, 6833 |
Rint | 0.074 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.054, 0.127, 1.01 |
No. of reflections | 9751 |
No. of parameters | 515 |
No. of restraints | 24 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
w = 1/[σ2(Fo2) + (0.0421P)2 + 26.2686P] where P = (Fo2 + 2Fc2)/3 | |
Δρmax, Δρmin (e Å−3) | 1.41, −1.01 |
Computer programs: PROCESS-AUTO (Rigaku, 1998), PROCESS-AUTO, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL-Plus (Sheldrick, 1990), SHELXL97.
Cd1—N1 | 2.235 (5) | Cd1—O5 | 2.380 (4) |
Cd1—N3 | 2.266 (5) | Cd1—O6 | 2.357 (4) |
Cd2—N5 | 2.269 (4) | Cd1—O8i | 2.355 (3) |
Cd2—N7 | 2.244 (5) | Cd1—O7i | 2.419 (4) |
Cd2—O1 | 2.397 (4) | Cd2—O3ii | 2.279 (5) |
Cd2—O2 | 2.347 (4) | Cd2—O4ii | 2.457 (4) |
N1—Cd1—N3 | 93.62 (19) | N7—Cd2—N5 | 92.99 (18) |
N1—Cd1—O8i | 100.17 (15) | N7—Cd2—O3ii | 124.4 (2) |
N3—Cd1—O8i | 109.32 (16) | N5—Cd2—O3ii | 91.99 (19) |
N1—Cd1—O6 | 98.18 (18) | N7—Cd2—O2 | 97.27 (17) |
N3—Cd1—O6 | 91.94 (15) | N5—Cd2—O2 | 131.71 (17) |
O8i—Cd1—O6 | 150.77 (15) | O3ii—Cd2—O2 | 119.0 (2) |
N1—Cd1—O5 | 100.37 (18) | N7—Cd2—O1 | 139.16 (18) |
N3—Cd1—O5 | 144.75 (15) | N5—Cd2—O1 | 90.09 (16) |
O8i—Cd1—O5 | 99.87 (13) | O3ii—Cd2—O1 | 96.1 (2) |
O6—Cd1—O5 | 54.29 (13) | O2—Cd2—O1 | 53.20 (14) |
N1—Cd1—O7i | 153.96 (16) | N7—Cd2—O4ii | 93.16 (18) |
N3—Cd1—O7i | 90.96 (17) | N5—Cd2—O4ii | 139.08 (18) |
O8i—Cd1—O7i | 54.33 (11) | O3ii—Cd2—O4ii | 52.18 (15) |
O6—Cd1—O7i | 107.27 (15) | O2—Cd2—O4ii | 87.38 (17) |
O5—Cd1—O7i | 90.33 (15) | O1—Cd2—O4ii | 110.49 (19) |
Symmetry codes: (i) x+1/2, y, −z+3/2; (ii) −x+1/2, y+1/2, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—HW11···O2 | 0.87 (5) | 1.88 (5) | 2.737 (6) | 169 (7) |
O2W—HW21···O4 | 0.85 (5) | 1.92 (3) | 2.708 (6) | 153 (6) |
O2W—HW22···O8iii | 0.844 (19) | 1.97 (2) | 2.814 (5) | 173 (5) |
O3W—HW32···O3 | 0.86 (6) | 1.90 (4) | 2.727 (7) | 160 (8) |
O3W—HW31···O4Wiv | 0.87 (6) | 1.89 (6) | 2.758 (8) | 176 (9) |
O4W—HW41···O1 | 0.87 (7) | 1.97 (8) | 2.797 (7) | 160 (7) |
O4W—HW42···O2Wv | 0.87 (6) | 1.90 (3) | 2.756 (7) | 170 (9) |
N2—H2···O3W | 0.86 | 1.86 | 2.712 (7) | 170.6 |
N4—H4A···O5vi | 0.86 | 1.99 | 2.845 (6) | 170.5 |
N6—H6A···O7 | 0.86 | 1.93 | 2.776 (6) | 167.3 |
N8—H8···O1Wvii | 0.86 | 1.98 | 2.839 (7) | 173.2 |
Symmetry codes: (iii) −x+1/2, −y, z+1/2; (iv) −x+1/2, y−1/2, z; (v) −x+1, −y, −z+2; (vi) −x+1, y−1/2, −z+3/2; (vii) −x, −y, −z+2. |
Helical structures have received much attention in coordination chemistry and materials chemistry (Lehn, 1990). So far, many helical complexes have been generated by self-assembly processes (Chen & Liu, 2002). An appropriate flexible bidentate organic acid bridge could be useful in the formation of helical chains in the presence of secondary ligands, such as 2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen) (Li et al., 2002). The N atoms from the secondary ligand may occupy two coordination positions of metal ions. The rest of the coordination positions are available for other carboxylate ligands to allow the formation of a helix. We selected cyclohexane-1,4-dicarboxylic acid (1,4-chdcH2) as a bridging ligand and 2-methyl-1H-imidazole (mi) as a secondary ligand, generating a new helical chain coordination polymer, [Cd(1,4-chdc)(mi)2].2H2O, (I), which is reported here.
In compound (I), the asymmetric unit contains two crystallographically nonequivalent CdII atoms (Cd1 and Cd2), two 1,4-chdc anions, four mi ligands, and four free water molecules (Fig. 1). Each CdII atom is six-coordinated by two N atoms from two mi molecules, and four O atoms from two 1,4-chdc ligands in a distorted octahedral environment (Fig. 1). The Cd—O distances range from 2.279 (5) to 2.457 (4) Å, and the Cd—N distances vary from 2.235 (5) to 2.269 (4) Å (Table 1). As shown in Fig. 2, each 1,4-chdc moiety acts as a bis-chelating ligand that binds two CdII atoms, forming two unique helical chains. These chains are decorated with mi ligands alternately at two sides. Furthermore, the O—H···O and N—H···O hydrogen bonds (Table 2) link the chains together, forming a three-dimensional supramolecular structure of (I). There are weak π—π interactions between 2-methyl- 1H-imidazole ligands in neighboring chains at (x, y, z) and (-x, -y, 2 - z), with the interplanar distance of 3.62 (2) Å.