Acta Cryst. (2010). E66, o243 [ doi:10.1107/S160053680905435X ]
In the crystal structure of the title compound, C7H4Cl2O, the molecules form a network of weak C-H
O interactions involving the aldehyde O atom and the ortho-H atom on the benzene ring together with C-HO interactions between the formyl groups. Together, these connect the molecules into (10
) layers, which are stabilized additionally by ![[pi]](/logos/entities/pi_rmgif.gif)
- stacking interactions of the benzene rings [centroid-centroid distance = 3.772 (1) Å]. The aldehyde group is twisted relative to the benzene ring by 7.94 (13)°.
2,4-dichlorobenzaldehyde was purchased from ALDRICH (99% purity, lot 08722CD). The compound was provided in crystalline form.
All hydrogen atoms were localized using the difference density Fourier map. Their positions and isotropic displacement parameters were refined.
Data collection: HKL-2000 (Otwinowski & Minor, 1997); cell refinement: HKL-2000 (Otwinowski & Minor, 1997); data reduction: HKL-2000 (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008) and HKL-3000SM (Minor et al., 2006); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) and HKL-3000SM (Minor et al., 2006); molecular graphics: HKL-3000SM (Minor et al., 2006), ORTEPIII (Burnett & Johnson, 1996), ORTEP-3 (Farrugia, 1997), Mercury (Macrae et al., 2006) and POV-RAY (The POV-RAY Team, 2004); software used to prepare material for publication: HKL-3000SM.
![[Figure 1]](./gk2246fig1thm.gif)
| Fig. 1. The asymmetric unit of the reported structure. Displacement ellipsoids are drawn at the 50% probability level and hydrogen atoms are drawn as grey spheres of an arbitrary radius. |
![[Figure 2]](./gk2246fig2thm.gif)
| Fig. 2. The molecular packing of 2,4-dichlorobenzaldehyde. Weak interactions, in which the oxygen atom participates, are shown as blue, dashed lines. |
| C7H4Cl2O | F(000) = 352 |
| Mr = 175.01 | Dx = 1.677 Mg m−3 |
| Monoclinic, P21/n | Mo Kα radiation, λ = 0.71074 Å |
| Hall symbol: -P 2yn | Cell parameters from 31891 reflections |
| a = 13.100 (1) Å | θ = 1.0–37.8° |
| b = 3.772 (1) Å | µ = 0.85 mm−1 |
| c = 15.332 (1) Å | T = 100 K |
| β = 113.797 (2)° | Block, colorless |
| V = 693.2 (3) Å3 | 0.40 × 0.10 × 0.10 mm |
| Z = 4 |
| Rigaku R-AXIS RAPID diffractometer | 3737 independent reflections |
| Radiation source: fine-focus sealed tube | 3221 reflections with I > 2σ(I) |
| graphite | Rint = 0.063 |
| Detector resolution: 10 pixels mm-1 | θmax = 37.8°, θmin = 1.0° |
| ω scans | h = −22→22 |
| Absorption correction: multi-scan (Otwinowski et al., 2003) | k = −6→6 |
| Tmin = 0.90, Tmax = 0.92 | l = −26→24 |
| 6924 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)] = 0.036 | Hydrogen site location: difference Fourier map |
| wR(F2) = 0.114 | All H-atom parameters refined |
| S = 1.10 | w = 1/[σ2(Fo2) + (0.0708P)2 + 0.0197P] where P = (Fo2 + 2Fc2)/3 |
| 3737 reflections | (Δ/σ)max = 0.001 |
| 107 parameters | Δρmax = 0.67 e Å−3 |
| 0 restraints | Δρmin = −0.41 e Å−3 |
| C7H4Cl2O | V = 693.2 (3) Å3 |
| Mr = 175.01 | Z = 4 |
| Monoclinic, P21/n | Mo Kα radiation |
| a = 13.100 (1) Å | µ = 0.85 mm−1 |
| b = 3.772 (1) Å | T = 100 K |
| c = 15.332 (1) Å | 0.40 × 0.10 × 0.10 mm |
| β = 113.797 (2)° |
| Rigaku R-AXIS RAPID diffractometer | 3737 independent reflections |
| Absorption correction: multi-scan (Otwinowski et al., 2003) | 3221 reflections with I > 2σ(I) |
| Tmin = 0.90, Tmax = 0.92 | Rint = 0.063 |
| 6924 measured reflections | θmax = 37.8° |
| R[F2 > 2σ(F2)] = 0.036 | All H-atom parameters refined |
| wR(F2) = 0.114 | Δρmax = 0.67 e Å−3 |
| S = 1.10 | Δρmin = −0.41 e Å−3 |
| 3737 reflections | Absolute structure: ? |
| 107 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 | ||
| Cl2 | 0.138241 (15) | 0.17792 (6) | 0.579292 (15) | 0.02422 (7) | |
| Cl1 | 0.558151 (16) | 0.15135 (6) | 0.840216 (14) | 0.02526 (7) | |
| C1 | 0.49878 (6) | −0.1166 (2) | 0.66074 (6) | 0.01968 (13) | |
| C3 | 0.35318 (6) | 0.1385 (2) | 0.70157 (6) | 0.02006 (14) | |
| C2 | 0.46410 (6) | 0.0484 (2) | 0.72565 (5) | 0.01980 (13) | |
| C6 | 0.41880 (6) | −0.1866 (2) | 0.56890 (6) | 0.02060 (14) | |
| C5 | 0.30765 (6) | −0.0964 (2) | 0.54240 (6) | 0.02080 (13) | |
| C4 | 0.27652 (6) | 0.0634 (2) | 0.60987 (5) | 0.01992 (13) | |
| O1 | 0.64561 (5) | −0.4059 (2) | 0.63526 (5) | 0.02975 (14) | |
| C7 | 0.61622 (6) | −0.2245 (2) | 0.68671 (6) | 0.02340 (14) | |
| H3 | 0.3319 (13) | 0.260 (4) | 0.7450 (12) | 0.038 (3)* | |
| H5 | 0.2576 (13) | −0.150 (4) | 0.4813 (13) | 0.042 (4)* | |
| H6 | 0.4423 (13) | −0.293 (5) | 0.5239 (12) | 0.046 (4)* | |
| H7 | 0.6686 (14) | −0.131 (4) | 0.7449 (13) | 0.041 (4)* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Cl2 | 0.01697 (10) | 0.02944 (12) | 0.02558 (11) | 0.00285 (6) | 0.00789 (8) | 0.00236 (6) |
| Cl1 | 0.02130 (11) | 0.02926 (12) | 0.02104 (11) | −0.00059 (6) | 0.00422 (8) | −0.00518 (6) |
| C1 | 0.0165 (3) | 0.0207 (3) | 0.0213 (3) | −0.0005 (2) | 0.0071 (2) | −0.0007 (2) |
| C3 | 0.0190 (3) | 0.0209 (3) | 0.0206 (3) | 0.0003 (2) | 0.0083 (3) | −0.0003 (2) |
| C2 | 0.0182 (3) | 0.0203 (3) | 0.0195 (3) | −0.0014 (2) | 0.0062 (2) | −0.0017 (2) |
| C6 | 0.0189 (3) | 0.0226 (3) | 0.0206 (3) | −0.0002 (2) | 0.0082 (2) | −0.0008 (2) |
| C5 | 0.0185 (3) | 0.0229 (3) | 0.0195 (3) | −0.0007 (2) | 0.0061 (2) | −0.0008 (2) |
| C4 | 0.0168 (3) | 0.0209 (3) | 0.0215 (3) | 0.0001 (2) | 0.0071 (2) | 0.0016 (2) |
| O1 | 0.0214 (3) | 0.0378 (3) | 0.0304 (3) | 0.0045 (2) | 0.0108 (2) | −0.0046 (3) |
| C7 | 0.0178 (3) | 0.0266 (3) | 0.0251 (3) | −0.0001 (3) | 0.0080 (3) | −0.0013 (3) |
| Cl2—C4 | 1.7327 (7) | C3—H3 | 0.939 (17) |
| Cl1—C2 | 1.7343 (8) | C6—C5 | 1.3869 (11) |
| C1—C2 | 1.3961 (11) | C6—H6 | 0.950 (19) |
| C1—C6 | 1.3999 (11) | C5—C4 | 1.3930 (11) |
| C1—C7 | 1.4820 (11) | C5—H5 | 0.923 (18) |
| C3—C4 | 1.3877 (11) | O1—C7 | 1.2180 (11) |
| C3—C2 | 1.3893 (11) | C7—H7 | 0.946 (17) |
| C2—C1—C6 | 118.32 (7) | C1—C6—H6 | 118.6 (9) |
| C2—C1—C7 | 122.14 (7) | C6—C5—C4 | 118.43 (7) |
| C6—C1—C7 | 119.53 (7) | C6—C5—H5 | 118.4 (10) |
| C4—C3—C2 | 118.11 (7) | C4—C5—H5 | 123.2 (10) |
| C4—C3—H3 | 121.2 (10) | C3—C4—C5 | 122.11 (7) |
| C2—C3—H3 | 120.6 (10) | C3—C4—Cl2 | 118.26 (6) |
| C3—C2—C1 | 121.73 (7) | C5—C4—Cl2 | 119.62 (6) |
| C3—C2—Cl1 | 116.99 (6) | O1—C7—C1 | 123.05 (8) |
| C1—C2—Cl1 | 121.28 (6) | O1—C7—H7 | 121.4 (10) |
| C5—C6—C1 | 121.30 (7) | C1—C7—H7 | 115.5 (10) |
| C5—C6—H6 | 120.0 (9) | ||
| C4—C3—C2—C1 | −0.72 (12) | C1—C6—C5—C4 | −0.68 (12) |
| C4—C3—C2—Cl1 | 179.11 (6) | C2—C3—C4—C5 | −0.19 (12) |
| C6—C1—C2—C3 | 0.90 (12) | C2—C3—C4—Cl2 | −179.59 (6) |
| C7—C1—C2—C3 | −177.92 (8) | C6—C5—C4—C3 | 0.88 (12) |
| C6—C1—C2—Cl1 | −178.92 (6) | C6—C5—C4—Cl2 | −179.73 (6) |
| C7—C1—C2—Cl1 | 2.26 (11) | C2—C1—C7—O1 | 170.86 (9) |
| C2—C1—C6—C5 | −0.18 (12) | C6—C1—C7—O1 | −7.94 (13) |
| C7—C1—C6—C5 | 178.67 (7) |
| D—H···A | D—H | H···A | D···A | D—H···A |
| C7—H7···O1i | 0.946 (17) | 2.533 (17) | 3.4289 (11) | 158.0 (14) |
| C6—H6···O1ii | 0.950 (19) | 2.512 (17) | 3.2774 (11) | 137.8 (12) |
| Symmetry codes: (i) −x+3/2, y+1/2, −z+3/2; (ii) −x+1, −y−1, −z+1. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| C7—H7···O1i | 0.946 (17) | 2.533 (17) | 3.4289 (11) | 158.0 (14) |
| C6—H6···O1ii | 0.950 (19) | 2.512 (17) | 3.2774 (11) | 137.8 (12) |
| Symmetry codes: (i) −x+3/2, y+1/2, −z+3/2; (ii) −x+1, −y−1, −z+1. |
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2,4-Dichlorobenzaldehyde is primarily used in the preparation of dyes, insecticides, herbicides, antiseptics and disinfectants (Wang et al., 2004). It is also used as an intermediate of organic synthesis of fungicide diniconazole (Katagi, 1988).
In the crystal structure of 2,4-dichlorobenzaldehyde (Fig. 1), the aldehyde group is twisted relative to the benzene ring with torsion angles C6—C1—C7—O1 and C2—C1—C7—O1 being -7.94 (13)° and 170.86 (9)°. These torsion angles are significantly smaller in comparison to the corresponding angles in 2,6-dichlorobenzaldehyde (Gawlicka-Chruszcz et al., 2006) which are -27.3° and 152.6° respectively. Significantly bigger twist of the aldehyde group in the case of 2,6-dichlorobenzaldehyde is caused by presence of the chlorine atoms in ortho positions.
The change of the position of chlorine atom causes that interactions in which chlorine atoms are involved in 2,4-dichlorobenzaldehyde and 2,6-dichlorobenzaldehyde differ significantly. In the case of 2,6-dichlorobenzaldehyde Cl2 was involved in weak interaction with hydrogen atom from neighboring benzene ring, while in 2,4-dichlorobenzaldehyde structure such interactions are not observed for any of the chlorine atoms. However, in the case of 2,4-dichlorobenzaldehyde, the chlorine atoms from neighboring molecules form short contacts with Cl1···Cl2 (1/2 + x,1/2 - y,1/2 + z) distance being 3.442Å (Fig. 2).
The weak O···H—C interactions (Table 1) between the aldehyde oxygen and the benzene hydrogen atoms connect molecules to form layers, which are additionally stabilized by stacking of benzene rings (Fig. 2). The oxygen atom from the aldehyde group plays a central role in the formation of weak interactions, and O1···H6—C6 (1 - x,-1 - y,1 - z) and O1···H7—C7 (1,5 - x,-1/2 + y,1.5 - z) distances are 2.51Å and 2.53Å respectively.