Acta Cryst. (2007). E63, o2795 [ doi:10.1107/S1600536807020983 ]
The title compound, C8H7IO3, contains two independent molecules, each lying on a mirror plane. The two molecules differ in the orientation of the -CHO group by a 180° rotation around its bond with the benzene ring. In the mirror plane, each independent molecule is linked to a symmetry-equivalent molecule by intermolecular O-H
O hydrogen bonds, forming a chain along the b axis. Short intermolecular IO contacts are observed between adjacent chains.
4-Hydroxy-3-iodo-5-methoxy-benzaldehyde (1 g) was added to an anhydrous ethanol (50 ml), with stirring at 350 K. The resulting yellow solution was filtered and the filtrate was allowed to stand in air at room temperature for 10 d, yielding yellow crystals of (I)
H atoms were placed in calculated positions [O—H = 0.82 Å and C—H = 0.93 (aromatic) or 0.96 Å (methyl)] and refined using a riding model, with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(O).
Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); 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, 1997); software used to prepare material for publication: SHELXTL.
![[Figure 1]](./ci2356fig1thm.gif)
| Fig. 1. The asymmetric unit of (I). Displacement ellipsoids are drawn at the 30% probability level. |
![[Figure 2]](./ci2356fig2thm.gif)
| Fig. 2. Hydrogen-bonded (dashed lines) chains formed by one of the independent molecules, viewed down the c axis. |
![[Figure 3]](./ci2356fig3thm.gif)
| Fig. 3. Hydrogen-bonded (dashed lines) chains formed by other independent molecules, viewed down the c axis. |
| C8H7IO3 | F(000) = 1056 |
| Mr = 278.04 | Dx = 2.098 Mg m−3 |
| Orthorhombic, Pbam | Mo Kα radiation, λ = 0.71073 Å |
| Hall symbol: -P 2 2ab | Cell parameters from 4592 reflections |
| a = 16.332 (2) Å | θ = 2.5–26.4° |
| b = 16.344 (2) Å | µ = 3.60 mm−1 |
| c = 6.5957 (12) Å | T = 293 K |
| V = 1760.6 (4) Å3 | Block, yellow |
| Z = 8 | 0.20 × 0.16 × 0.12 mm |
| Bruker SMART CCD area-detector diffractometer | 1974 independent reflections |
| Radiation source: fine-focus sealed tube | 1654 reflections with I > 2σ(I) |
| graphite | Rint = 0.037 |
| φ and ω scans | θmax = 26.4°, θmin = 1.8° |
| Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −16→20 |
| Tmin = 0.533, Tmax = 0.672 | k = −20→19 |
| 9744 measured reflections | l = −5→8 |
| 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)] = 0.022 | Hydrogen site location: inferred from neighbouring sites |
| wR(F2) = 0.053 | H-atom parameters constrained |
| S = 1.03 | w = 1/[σ2(Fo2) + (0.025P)2 + 0.749P] where P = (Fo2 + 2Fc2)/3 |
| 1974 reflections | (Δ/σ)max = 0.001 |
| 145 parameters | Δρmax = 0.47 e Å−3 |
| 0 restraints | Δρmin = −0.47 e Å−3 |
| C8H7IO3 | V = 1760.6 (4) Å3 |
| Mr = 278.04 | Z = 8 |
| Orthorhombic, Pbam | Mo Kα radiation |
| a = 16.332 (2) Å | µ = 3.60 mm−1 |
| b = 16.344 (2) Å | T = 293 K |
| c = 6.5957 (12) Å | 0.20 × 0.16 × 0.12 mm |
| Bruker SMART CCD area-detector diffractometer | 1974 independent reflections |
| Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1654 reflections with I > 2σ(I) |
| Tmin = 0.533, Tmax = 0.672 | Rint = 0.037 |
| 9744 measured reflections | θmax = 26.4° |
| R[F2 > 2σ(F2)] = 0.022 | H-atom parameters constrained |
| wR(F2) = 0.053 | Δρmax = 0.47 e Å−3 |
| S = 1.03 | Δρmin = −0.47 e Å−3 |
| 1974 reflections | Absolute structure: ? |
| 145 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
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 | ||
| I1 | −0.024919 (16) | 0.352244 (16) | 0.5000 | 0.03520 (9) | |
| O1 | 0.13388 (17) | 0.45773 (15) | 0.5000 | 0.0385 (7) | |
| H1O | 0.1744 | 0.4873 | 0.5000 | 0.058* | |
| O2 | 0.29270 (16) | 0.42133 (16) | 0.5000 | 0.0419 (7) | |
| O3 | 0.29135 (17) | 0.10050 (16) | 0.5000 | 0.0374 (7) | |
| C1 | 0.0976 (2) | 0.3182 (2) | 0.5000 | 0.0271 (8) | |
| C2 | 0.1575 (2) | 0.3788 (2) | 0.5000 | 0.0266 (8) | |
| C3 | 0.2406 (2) | 0.3558 (2) | 0.5000 | 0.0269 (8) | |
| C4 | 0.2620 (2) | 0.2753 (2) | 0.5000 | 0.0292 (8) | |
| H4 | 0.3170 | 0.2604 | 0.5000 | 0.035* | |
| C5 | 0.2013 (2) | 0.2148 (2) | 0.5000 | 0.0263 (8) | |
| C6 | 0.1193 (2) | 0.2362 (2) | 0.5000 | 0.0287 (8) | |
| H6 | 0.0791 | 0.1959 | 0.5000 | 0.034* | |
| C7 | 0.2227 (3) | 0.1278 (2) | 0.5000 | 0.0321 (9) | |
| H7 | 0.1797 | 0.0904 | 0.5000 | 0.038* | |
| C8 | 0.3785 (2) | 0.4039 (3) | 0.5000 | 0.0474 (12) | |
| H8A | 0.4087 | 0.4542 | 0.5000 | 0.071* | |
| H8B | 0.3921 | 0.3728 | 0.3812 | 0.071* | |
| I2 | 0.049445 (18) | 0.127572 (19) | 0.0000 | 0.04574 (11) | |
| O4 | 0.15122 (18) | −0.03449 (17) | 0.0000 | 0.0434 (7) | |
| H4O | 0.1763 | −0.0779 | 0.0000 | 0.065* | |
| O5 | 0.30938 (17) | −0.06768 (16) | 0.0000 | 0.0411 (7) | |
| O6 | 0.3560 (2) | 0.29765 (18) | 0.0000 | 0.0586 (9) | |
| C9 | 0.1756 (2) | 0.1081 (2) | 0.0000 | 0.0311 (9) | |
| C10 | 0.2044 (2) | 0.0276 (2) | 0.0000 | 0.0311 (9) | |
| C11 | 0.2889 (2) | 0.0137 (2) | 0.0000 | 0.0294 (8) | |
| C12 | 0.3422 (2) | 0.0785 (2) | 0.0000 | 0.0329 (9) | |
| H12 | 0.3984 | 0.0690 | 0.0000 | 0.039* | |
| C13 | 0.3128 (3) | 0.1583 (2) | 0.0000 | 0.0318 (9) | |
| C14 | 0.2296 (3) | 0.1732 (2) | 0.0000 | 0.0352 (10) | |
| H14 | 0.2101 | 0.2266 | 0.0000 | 0.042* | |
| C15 | 0.3720 (3) | 0.2257 (3) | 0.0000 | 0.0402 (10) | |
| H15 | 0.4271 | 0.2115 | 0.0000 | 0.048* | |
| C16 | 0.3938 (3) | −0.0866 (3) | 0.0000 | 0.0475 (11) | |
| H16A | 0.4008 | −0.1449 | 0.0000 | 0.071* | |
| H16B | 0.4190 | −0.0638 | 0.1188 | 0.071* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| I1 | 0.02010 (14) | 0.03288 (15) | 0.05262 (19) | 0.00134 (10) | 0.000 | 0.000 |
| O1 | 0.0261 (15) | 0.0192 (13) | 0.070 (2) | −0.0014 (11) | 0.000 | 0.000 |
| O2 | 0.0207 (14) | 0.0257 (14) | 0.079 (2) | −0.0031 (11) | 0.000 | 0.000 |
| O3 | 0.0319 (16) | 0.0232 (14) | 0.0570 (19) | 0.0058 (12) | 0.000 | 0.000 |
| C1 | 0.0181 (19) | 0.0271 (18) | 0.036 (2) | −0.0006 (15) | 0.000 | 0.000 |
| C2 | 0.025 (2) | 0.0206 (17) | 0.034 (2) | 0.0020 (14) | 0.000 | 0.000 |
| C3 | 0.022 (2) | 0.0205 (18) | 0.038 (2) | −0.0034 (14) | 0.000 | 0.000 |
| C4 | 0.023 (2) | 0.0285 (19) | 0.036 (2) | 0.0047 (15) | 0.000 | 0.000 |
| C5 | 0.028 (2) | 0.0206 (17) | 0.030 (2) | 0.0040 (15) | 0.000 | 0.000 |
| C6 | 0.028 (2) | 0.0242 (19) | 0.034 (2) | −0.0050 (15) | 0.000 | 0.000 |
| C7 | 0.035 (2) | 0.0199 (18) | 0.042 (2) | 0.0007 (16) | 0.000 | 0.000 |
| C8 | 0.020 (2) | 0.045 (3) | 0.077 (3) | −0.0009 (19) | 0.000 | 0.000 |
| I2 | 0.02894 (17) | 0.05050 (19) | 0.0578 (2) | 0.00543 (12) | 0.000 | 0.000 |
| O4 | 0.0333 (16) | 0.0306 (15) | 0.066 (2) | −0.0051 (12) | 0.000 | 0.000 |
| O5 | 0.0323 (16) | 0.0268 (14) | 0.064 (2) | 0.0049 (12) | 0.000 | 0.000 |
| O6 | 0.067 (2) | 0.0269 (16) | 0.082 (2) | −0.0079 (15) | 0.000 | 0.000 |
| C9 | 0.025 (2) | 0.034 (2) | 0.034 (2) | 0.0051 (17) | 0.000 | 0.000 |
| C10 | 0.031 (2) | 0.0284 (19) | 0.034 (2) | −0.0059 (16) | 0.000 | 0.000 |
| C11 | 0.032 (2) | 0.0216 (19) | 0.035 (2) | 0.0016 (16) | 0.000 | 0.000 |
| C12 | 0.028 (2) | 0.036 (2) | 0.035 (2) | −0.0005 (17) | 0.000 | 0.000 |
| C13 | 0.040 (2) | 0.0248 (19) | 0.030 (2) | −0.0032 (17) | 0.000 | 0.000 |
| C14 | 0.041 (3) | 0.026 (2) | 0.038 (2) | 0.0044 (18) | 0.000 | 0.000 |
| C15 | 0.037 (3) | 0.038 (2) | 0.045 (3) | −0.0093 (19) | 0.000 | 0.000 |
| C16 | 0.039 (3) | 0.038 (2) | 0.065 (3) | 0.014 (2) | 0.000 | 0.000 |
| I1—C1 | 2.077 (4) | I2—C9 | 2.085 (4) |
| O1—C2 | 1.347 (4) | O4—C10 | 1.336 (4) |
| O1—H1O | 0.8200 | O4—H4O | 0.82 |
| O2—C3 | 1.368 (4) | O5—C11 | 1.371 (4) |
| O2—C8 | 1.430 (5) | O5—C16 | 1.413 (5) |
| O3—C7 | 1.207 (5) | O6—C15 | 1.205 (5) |
| C1—C6 | 1.386 (5) | C9—C14 | 1.382 (6) |
| C1—C2 | 1.392 (5) | C9—C10 | 1.396 (5) |
| C2—C3 | 1.408 (5) | C10—C11 | 1.399 (5) |
| C3—C4 | 1.363 (5) | C11—C12 | 1.371 (5) |
| C4—C5 | 1.400 (5) | C12—C13 | 1.390 (5) |
| C4—H4 | 0.93 | C12—H12 | 0.93 |
| C5—C6 | 1.384 (5) | C13—C14 | 1.379 (6) |
| C5—C7 | 1.464 (5) | C13—C15 | 1.465 (5) |
| C6—H6 | 0.93 | C14—H14 | 0.93 |
| C7—H7 | 0.93 | C15—H15 | 0.93 |
| C8—H8A | 0.96 | C16—H16A | 0.96 |
| C8—H8B | 0.96 | C16—H16B | 0.96 |
| C2—O1—H1O | 109.5 | C10—O4—H4O | 109.5 |
| C3—O2—C8 | 117.0 (3) | C11—O5—C16 | 116.8 (3) |
| C6—C1—C2 | 120.5 (3) | C14—C9—C10 | 120.7 (4) |
| C6—C1—I1 | 120.4 (3) | C14—C9—I2 | 120.9 (3) |
| C2—C1—I1 | 119.1 (3) | C10—C9—I2 | 118.4 (3) |
| O1—C2—C1 | 118.7 (3) | O4—C10—C9 | 119.8 (4) |
| O1—C2—C3 | 122.1 (3) | O4—C10—C11 | 121.1 (3) |
| C1—C2—C3 | 119.2 (3) | C9—C10—C11 | 119.0 (3) |
| C4—C3—O2 | 126.7 (3) | C12—C11—O5 | 126.4 (4) |
| C4—C3—C2 | 120.3 (3) | C12—C11—C10 | 120.1 (3) |
| O2—C3—C2 | 113.0 (3) | O5—C11—C10 | 113.5 (3) |
| C3—C4—C5 | 120.1 (3) | C11—C12—C13 | 120.3 (4) |
| C3—C4—H4 | 120.0 | C11—C12—H12 | 119.8 |
| C5—C4—H4 | 120.0 | C13—C12—H12 | 119.8 |
| C6—C5—C4 | 120.4 (3) | C14—C13—C12 | 120.4 (4) |
| C6—C5—C7 | 118.5 (3) | C14—C13—C15 | 121.1 (4) |
| C4—C5—C7 | 121.1 (3) | C12—C13—C15 | 118.5 (4) |
| C5—C6—C1 | 119.5 (3) | C13—C14—C9 | 119.5 (4) |
| C5—C6—H6 | 120.2 | C13—C14—H14 | 120.2 |
| C1—C6—H6 | 120.2 | C9—C14—H14 | 120.2 |
| O3—C7—C5 | 125.5 (4) | O6—C15—C13 | 126.2 (4) |
| O3—C7—H7 | 117.3 | O6—C15—H15 | 116.9 |
| C5—C7—H7 | 117.3 | C13—C15—H15 | 116.9 |
| O2—C8—H8A | 109.5 | O5—C16—H16A | 109.5 |
| O2—C8—H8B | 109.5 | O5—C16—H16B | 109.5 |
| H8A—C8—H8B | 109.5 | H16A—C16—H16B | 109.5 |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O1—H1O···O2 | 0.82 | 2.21 | 2.661 (4) | 115 |
| O1—H1O···O3i | 0.82 | 1.93 | 2.634 (4) | 143 |
| O4—H4O···O5 | 0.82 | 2.18 | 2.639 (4) | 116 |
| O4—H4O···O6ii | 0.82 | 2.10 | 2.746 (4) | 135 |
| Symmetry codes: (i) −x+1/2, y+1/2, −z+1; (ii) −x+1/2, y−1/2, −z. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O1—H1O···O2 | 0.82 | 2.21 | 2.661 (4) | 115 |
| O1—H1O···O3i | 0.82 | 1.93 | 2.634 (4) | 143 |
| O4—H4O···O5 | 0.82 | 2.18 | 2.639 (4) | 116 |
| O4—H4O···O6ii | 0.82 | 2.10 | 2.746 (4) | 135 |
| Symmetry codes: (i) −x+1/2, y+1/2, −z+1; (ii) −x+1/2, y−1/2, −z. |
This work was supported by the National Natural Science Foundation of China (grant No. 20576066).
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In order to establish control over the preparation of crystalline solid materials so that their architecture and properties are predictable (Belloni et al., 2005; Tynan et al., 2005; Parashar et al., 1988), the synthesis of new and designed crystal structures has become a major strand of modern chemistry. Metal complexes based on Schiff bases have attracted much attention because they can be utilized as model compounds of the active centres
in various proteins and enzymes (Kahwa et al., 1986; Santos et al., 2001). As part of an investigation of the coordination properties of Shiff bases functioning as ligands, we report the synthesis and crystal structure of the title compound, (I).
The asymmetric unit of (I) comprises two independent molecules (Fig. 1), lying on the mirror planes, one at z = 0 and the other at z = 1/2. The two molecules differ in the orientation of the –CHO group by a 180° rotation around its bond with the benzene ring. In both molecules the geometric parameters are normal.
Each independent molecule is linked to a symmetry-equivalent molecule by intermolecular O—H···O hydrogen bonds, forming a chain along the b axis, in the mirror plane. The chains formed by each independent molecule are shown in Fig.2 and Fig.3. Short intermolecular I1···O3(x - 1/2, 1/2 - y, 1 - z) [3.099 (3) Å] and I2···O6(x - 1/2, 1/2 - y, -z) [3.388 (3) Å] contacts are observed between the adjacent chains.]