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Acta Crystallogr Sect E Struct Rep Online. 2010 July 1; 66(Pt 7): o1806.
Published online 2010 June 26. doi:  10.1107/S1600536810023548
PMCID: PMC3006813

1,4-Dibromo-2,5-dimeth­oxy­benzene

Abstract

The asymmetric unit of the title compound, C8H8Br2O2, contains one half-mol­ecule, the complete mol­ecule being generated by inversion symmetry.

Related literature

For standard bond lengths, see: Allen et al. (1987 [triangle]). For the synthetic procedure, see: Lopez-Alvarado et al. (2002 [triangle]). For potential uses of compounds derived from the title compound, see: Chen et al. (2006 [triangle]).

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Object name is e-66-o1806-scheme1.jpg

Experimental

Crystal data

  • C8H8Br2O2
  • M r = 295.94
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o1806-efi1.jpg
  • a = 6.573 (1) Å
  • b = 8.438 (2) Å
  • c = 8.756 (2) Å
  • β = 90.14 (3)°
  • V = 485.6 (2) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 8.30 mm−1
  • T = 298 K
  • 0.20 × 0.10 × 0.10 mm

Data collection

  • Enraf–Nonius CAD-4 diffractometer
  • Absorption correction: ψ scan (North et al., 1968 [triangle]) T min = 0.288, T max = 0.491
  • 1761 measured reflections
  • 884 independent reflections
  • 622 reflections with I > 2σ(I)
  • R int = 0.112
  • 3 standard reflections every 200 reflections intensity decay: 1%

Refinement

  • R[F 2 > 2σ(F 2)] = 0.044
  • wR(F 2) = 0.102
  • S = 1.01
  • 884 reflections
  • 55 parameters
  • H-atom parameters constrained
  • Δρmax = 0.58 e Å−3
  • Δρmin = −0.41 e Å−3

Data collection: CAD-4 Software (Enraf–Nonius, 1985 [triangle]); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995 [triangle]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, lzh. DOI: 10.1107/S1600536810023548/im2205sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810023548/im2205Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

The authors thank the Center of Testing and Analysis, Nanjing University, for support.

supplementary crystallographic information

Comment

The title compound, 1,4-dibromo-2,5-dimethoxybenzene is an important intermediate in the synthesis of 4-(2',5'-dimethoxy-4'-acetylthiophenyl)phenyl-nonafluorobiphenyl, which can be used as molecular switch, transistor and in the manufacture of memory devices (Chen et al., 2006). We report here the crystal structure of the title compound, (I).

The molecular structure of (I) is shown in Fig. 1. Bond lengths and angles are within normal ranges (Allen et al., 1987).

The benzene ring is planar and it's center respresents a crystallographic center of inversion. So only half of the molecule was observed in the asymmetric unit. No hydrogen bond interactions were observed in the crystal structure.

Experimental

The title compound, (I) was synthesized according to a literature method reported before (Lopez-Alvarado et al., 2002). Single crystals were obtained by slow evaporation of a methanolic (25 ml) solution of the compound (0.30 g, 1.0 mmol) at room temperature for about 15 d.

Refinement

H atoms were positioned geometrically, with C—H = 0.93 Å for aromatic H and 0.96 Å for methyl H, and constrained to ride on their parent atoms, with Uiso(H) = xUeq(C/O), where x = 1.2 for aromatic H and x = 1.5 for other H.

Figures

Fig. 1.
Molecular structure of the title compound showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 40% probability level.
Fig. 2.
Molecular packing of the title compound.

Crystal data

C8H8Br2O2F(000) = 284
Mr = 295.94Dx = 2.024 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 25 reflections
a = 6.573 (1) Åθ = 9–13°
b = 8.438 (2) ŵ = 8.30 mm1
c = 8.756 (2) ÅT = 298 K
β = 90.14 (3)°Block, colourless
V = 485.6 (2) Å30.20 × 0.10 × 0.10 mm
Z = 2

Data collection

Enraf–Nonius CAD-4 diffractometer622 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.112
graphiteθmax = 25.3°, θmin = 3.4°
ω/2θ scansh = −7→7
Absorption correction: ψ scan (North et al., 1968)k = −10→0
Tmin = 0.288, Tmax = 0.491l = −10→10
1761 measured reflections3 standard reflections every 200 reflections
884 independent reflections intensity decay: 1%

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.044Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.102H-atom parameters constrained
S = 1.01w = 1/[σ2(Fo2) + (0.03P)2 + 0.0P] where P = (Fo2 + 2Fc2)/3
884 reflections(Δ/σ)max < 0.001
55 parametersΔρmax = 0.58 e Å3
0 restraintsΔρmin = −0.41 e Å3

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

xyzUiso*/Ueq
Br0.26386 (11)0.73471 (7)0.78061 (8)0.0598 (3)
O−0.1091 (7)0.5578 (5)0.7000 (5)0.0551 (11)
C1−0.0605 (9)0.5256 (6)0.8479 (6)0.0394 (13)
C20.1090 (9)0.5986 (5)0.9077 (7)0.0400 (13)
C30.1721 (9)0.5752 (5)1.0558 (7)0.0433 (14)
H3A0.28810.62601.09220.052*
C4−0.2593 (11)0.4649 (8)0.6294 (8)0.0649 (19)
H4A−0.27750.49930.52570.097*
H4B−0.38520.47610.68370.097*
H4C−0.21810.35580.63040.097*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Br0.0762 (5)0.0516 (4)0.0517 (5)−0.0207 (3)0.0162 (3)0.0026 (3)
O0.065 (3)0.055 (2)0.045 (3)−0.011 (2)−0.004 (2)0.0031 (19)
C10.049 (3)0.036 (3)0.033 (3)0.002 (3)0.007 (3)−0.003 (2)
C20.047 (3)0.031 (3)0.042 (4)−0.004 (3)0.009 (3)−0.002 (2)
C30.049 (3)0.034 (3)0.046 (4)−0.006 (3)0.007 (3)−0.003 (2)
C40.070 (5)0.078 (4)0.047 (5)−0.004 (4)−0.014 (4)0.009 (4)

Geometric parameters (Å, °)

Br—C21.897 (5)C3—C1i1.405 (7)
O—C11.361 (7)C3—H3A0.9300
O—C41.403 (8)C4—H4A0.9600
C1—C21.375 (8)C4—H4B0.9600
C1—C3i1.405 (7)C4—H4C0.9600
C2—C31.375 (8)
C1—O—C4118.1 (5)C2—C3—H3A120.1
O—C1—C2117.4 (5)C1i—C3—H3A120.1
O—C1—C3i124.8 (5)O—C4—H4A109.5
C2—C1—C3i117.8 (5)O—C4—H4B109.5
C1—C2—C3122.5 (5)H4A—C4—H4B109.5
C1—C2—Br118.9 (4)O—C4—H4C109.5
C3—C2—Br118.6 (4)H4A—C4—H4C109.5
C2—C3—C1i119.7 (5)H4B—C4—H4C109.5
C4—O—C1—C2169.3 (5)O—C1—C2—Br−1.0 (6)
C4—O—C1—C3i−11.4 (8)C3i—C1—C2—Br179.7 (4)
O—C1—C2—C3179.8 (5)C1—C2—C3—C1i−0.5 (8)
C3i—C1—C2—C30.5 (8)Br—C2—C3—C1i−179.7 (4)

Symmetry codes: (i) −x, −y+1, −z+2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: IM2205).

References

  • Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.
  • Chen, Z. K., Huang, C., Yang, J. S., O’Shea, S. & Loh, K. P. (2006). National University of Singapore, Singapore. WO patent number. 2006093467.
  • Enraf–Nonius (1985). CAD-4 Software Enraf–Nonius, Delft, The Netherlands.
  • Harms, K. & Wocadlo, S. (1995). XCAD4 University of Marburg, Germany.
  • Lopez-Alvarado, P., Avendano, C. & Menendez, J. C. (2002). Synthetic. Commun.32, 3233–3239.
  • North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography