organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

(4,6-Di­bromo-m-phenyl­enedi­methyl­­idyne) tetra­acetate

aDepartment of Applied Chemistry, College of Science, Nanjing University of Technology, Nanjing 210009, People's Republic of China
*Correspondence e-mail: zhuhj@njut.edu.cn

(Received 15 November 2007; accepted 26 November 2007; online 6 December 2007)

The title mol­ecule, C16H16Br2O8, lies on a crystallographic twofold axis. Weak intra­molecular C—H⋯O hydrogen bonds may, in part, control the conformation of the mol­ecule. In the crystal structure, mol­ecules are connected into a two-dimensional network via weak inter­molecular C—H⋯O hydrogen bonds.

Related literature

For related literature, see: Allen et al. (1987[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.]); Mitchell et al. (1995[Mitchell, R. H., Iyer, V. S., Khalifa, N., Mahadevan, R., Venugopalan, S., Weerawarna, S. A. & Zhou, P. Z. (1995). J. Am. Chem. Soc. 117, 1514-1532.]).

[Scheme 1]

Experimental

Crystal data
  • C16H16Br2O8

  • Mr = 496.09

  • Orthorhombic, P b c n

  • a = 20.639 (4) Å

  • b = 10.150 (2) Å

  • c = 9.0880 (18) Å

  • V = 1903.8 (6) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 4.30 mm−1

  • T = 298 (2) K

  • 0.40 × 0.30 × 0.20 mm

Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • Absorption correction: ψ scan (North et al., 1968[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.]) Tmin = 0.278, Tmax = 0.480 (expected range = 0.245–0.423)

  • 3687 measured reflections

  • 1877 independent reflections

  • 805 reflections with I > 2σ(I)

  • Rint = 0.054

  • 3 standard reflections every 200 reflections intensity decay: none

Refinement
  • R[F2 > 2σ(F2)] = 0.067

  • wR(F2) = 0.130

  • S = 0.96

  • 1877 reflections

  • 107 parameters

  • 29 restraints

  • H-atom parameters constrained

  • Δρmax = 0.58 e Å−3

  • Δρmin = −0.49 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C4—H4A⋯O3 0.93 2.46 2.815 (7) 103
C5—H5A⋯O2 0.98 2.34 2.693 (9) 100
C7—H7C⋯O2i 0.96 2.37 3.318 (11) 170
Symmetry code: (i) [-x+{\script{3\over 2}}, -y+{\script{3\over 2}}, z+{\script{1\over 2}}].

Data collection: CAD-4 Software (Enraf–Nonius, 1985[Enraf-Nonius (1985). CAD-4 Software. Version 5.0. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); molecular graphics: SHELXTL (Bruker, 2000[Bruker (2000). SHELXTL. Bruker AXS Inc., Madison, Wisconsin, USA.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

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

The asymmetric unit contains one half-molecule; the full molecule being generated by a crystallographic twofold rotation axis. Weak intramolecular C—H···O hydrogen bonds may, in part, control the conformation of the molecule. In the crystal structure, molecules are connected into a two-dimensional network via weak intermolecular C—H···O hydrogen bonds. (Fig. 2).

Related literature top

For related literature, see: Allen et al. (1987); Mitchell et al. (1995).

Experimental top

The title compound was prepared by a previously reported method (Mitchell et al., 1995).

The crystals of the title compound, were obtained by dissolving (I) (2.00 g, 4.03 mmol) into acetone (50 ml), and evaporating the solvent slowly at room temperature for about 3 d.

Refinement top

H atoms were positioned geometrically, with C—H = 0.93 - 0.98Å and constrained to ride on their parent atoms, with Uiso(H) = xUeq(C), where x = 1.5 for methyl H and x = 1.2 for all other H atoms.

Structure description top

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

The asymmetric unit contains one half-molecule; the full molecule being generated by a crystallographic twofold rotation axis. Weak intramolecular C—H···O hydrogen bonds may, in part, control the conformation of the molecule. In the crystal structure, molecules are connected into a two-dimensional network via weak intermolecular C—H···O hydrogen bonds. (Fig. 2).

For related literature, see: Allen et al. (1987); Mitchell et al. (1995).

Computing details top

Data collection: CAD-4 Software (Enraf–Nonius, 1985); cell refinement: CAD-4 Software (Enraf–Nonius, 1985); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2000); software used to prepare material for publication: SHELXTL (Bruker, 2000).

Figures top
[Figure 1] Fig. 1. The molecular structure, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 40% probability level. Hydrogen bonds are shown by dashed lines. [Symmetry code: (A) -x + 1, y, -z + 1/2.]
[Figure 2] Fig. 2. The packing of the title compound with C—H···O hydrogen bonds are shown by dashed lines.
(4,6-Dibromo-m-phenylenedimethylidyne) tetraacetate top
Crystal data top
C16H16Br2O8F(000) = 984
Mr = 496.09Dx = 1.731 Mg m3
Orthorhombic, PbcnMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2abCell parameters from 25 reflections
a = 20.639 (4) Åθ = 10–14°
b = 10.150 (2) ŵ = 4.30 mm1
c = 9.0880 (18) ÅT = 298 K
V = 1903.8 (6) Å3Plate, colourless
Z = 40.40 × 0.30 × 0.20 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer
805 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.054
Graphite monochromatorθmax = 26.0°, θmin = 2.0°
ω/2θ scansh = 025
Absorption correction: ψ scan
(North et al., 1968)
k = 012
Tmin = 0.278, Tmax = 0.480l = 011
3687 measured reflections3 standard reflections every 200 reflections
1877 independent reflections intensity decay: none
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.067Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.130H-atom parameters constrained
S = 0.96 w = 1/[σ2(Fo2) + (0.02P)2 + 0.0P]
where P = (Fo2 + 2Fc2)/3
1877 reflections(Δ/σ)max = 0.001
107 parametersΔρmax = 0.58 e Å3
29 restraintsΔρmin = 0.49 e Å3
Crystal data top
C16H16Br2O8V = 1903.8 (6) Å3
Mr = 496.09Z = 4
Orthorhombic, PbcnMo Kα radiation
a = 20.639 (4) ŵ = 4.30 mm1
b = 10.150 (2) ÅT = 298 K
c = 9.0880 (18) Å0.40 × 0.30 × 0.20 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer
805 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.054
Tmin = 0.278, Tmax = 0.4803 standard reflections every 200 reflections
3687 measured reflections intensity decay: none
1877 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.06729 restraints
wR(F2) = 0.130H-atom parameters constrained
S = 0.96Δρmax = 0.58 e Å3
1877 reflectionsΔρmin = 0.49 e Å3
107 parameters
Special details top

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) top
xyzUiso*/Ueq
Br0.61944 (4)0.39329 (6)0.10603 (9)0.0671 (3)
O10.6622 (2)0.6733 (4)0.2433 (6)0.0456 (11)
O20.7386 (3)0.6717 (7)0.0680 (7)0.0852 (19)
O30.6065 (2)0.8406 (5)0.1438 (5)0.049
O40.5702 (3)0.8387 (5)0.0882 (6)0.0750 (17)
C10.50000.4229 (8)0.25000.042 (2)
H1A0.50000.33130.25000.051*
C20.5520 (3)0.4888 (6)0.1917 (7)0.0390 (16)
C30.5535 (3)0.6316 (6)0.1962 (7)0.0414 (17)
C40.50000.6958 (9)0.25000.037 (2)
H4A0.50000.78740.25000.044*
C50.6135 (3)0.6973 (7)0.1474 (7)0.041
H5A0.62560.66520.04940.049*
C60.7244 (4)0.6543 (8)0.1961 (9)0.052 (2)
C70.7671 (4)0.6004 (9)0.3066 (9)0.084 (3)
H7A0.80980.59060.26610.126*
H7B0.75130.51590.33750.126*
H7C0.76880.65880.38960.126*
C80.5877 (3)0.8970 (7)0.0164 (10)0.063 (2)
C90.5899 (4)1.0491 (6)0.0331 (9)0.060 (2)
H9A0.57611.08960.05710.090*
H9B0.63341.07620.05520.090*
H9C0.56161.07570.11160.090*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br0.0785 (5)0.0252 (4)0.0977 (6)0.0028 (4)0.0283 (5)0.0106 (5)
O10.055 (3)0.033 (2)0.049 (3)0.001 (2)0.007 (2)0.009 (3)
O20.064 (4)0.107 (5)0.084 (4)0.006 (4)0.024 (3)0.001 (4)
O30.0490.0490.0490.0000.0000.000
O40.095 (4)0.051 (3)0.080 (4)0.008 (3)0.023 (3)0.005 (4)
C10.058 (5)0.019 (4)0.049 (5)0.0000.010 (5)0.000
C20.051 (3)0.013 (3)0.053 (4)0.004 (3)0.011 (3)0.016 (3)
C30.058 (4)0.022 (3)0.045 (4)0.005 (3)0.008 (3)0.010 (3)
C40.051 (5)0.021 (4)0.040 (5)0.0000.005 (4)0.000
C50.0410.0410.0410.0000.0000.000
C60.058 (5)0.052 (5)0.046 (5)0.010 (4)0.010 (4)0.018 (4)
C70.067 (5)0.095 (8)0.090 (7)0.020 (6)0.000 (5)0.012 (6)
C80.037 (3)0.059 (5)0.094 (6)0.009 (4)0.011 (4)0.055 (6)
C90.077 (5)0.018 (3)0.084 (5)0.005 (4)0.004 (5)0.001 (5)
Geometric parameters (Å, º) top
Br—C21.866 (6)C3—C51.476 (9)
O1—C51.353 (7)C4—C3i1.372 (8)
O1—C61.366 (8)C4—H4A0.9300
O2—C61.213 (9)C5—H5A0.9800
O3—C81.349 (9)C6—C71.445 (10)
O3—C51.461 (9)C7—H7A0.9600
O4—C81.177 (8)C7—H7B0.9600
C1—C21.371 (7)C7—H7C0.9600
C1—C2i1.371 (7)C8—C91.552 (8)
C1—H1A0.9300C9—H9A0.9600
C2—C31.450 (8)C9—H9B0.9600
C3—C41.372 (8)C9—H9C0.9600
C5—O1—C6121.4 (6)C3—C5—H5A109.6
C8—O3—C5118.0 (5)O2—C6—O1120.5 (7)
C2—C1—C2i121.6 (8)O2—C6—C7125.0 (7)
C2—C1—H1A119.2O1—C6—C7114.1 (6)
C2i—C1—H1A119.2C6—C7—H7A109.5
C1—C2—C3119.6 (6)C6—C7—H7B109.5
C1—C2—Br119.4 (4)H7A—C7—H7B109.5
C3—C2—Br121.0 (5)C6—C7—H7C109.5
C4—C3—C2117.9 (6)H7A—C7—H7C109.5
C4—C3—C5124.6 (6)H7B—C7—H7C109.5
C2—C3—C5117.5 (6)O4—C8—O3124.6 (7)
C3i—C4—C3123.3 (8)O4—C8—C9126.0 (8)
C3i—C4—H4A118.4O3—C8—C9109.3 (6)
C3—C4—H4A118.4C8—C9—H9A109.5
O1—C5—O3105.5 (5)C8—C9—H9B109.5
O1—C5—C3110.4 (5)H9A—C9—H9B109.5
O3—C5—C3112.0 (5)C8—C9—H9C109.5
O1—C5—H5A109.6H9A—C9—H9C109.5
O3—C5—H5A109.6H9B—C9—H9C109.5
C2i—C1—C2—C32.3 (4)C8—O3—C5—O1147.6 (5)
C2i—C1—C2—Br177.1 (5)C8—O3—C5—C392.3 (7)
C1—C2—C3—C44.6 (9)C4—C3—C5—O1109.4 (6)
Br—C2—C3—C4174.8 (3)C2—C3—C5—O168.3 (8)
C1—C2—C3—C5173.3 (5)C4—C3—C5—O37.8 (8)
Br—C2—C3—C57.3 (9)C2—C3—C5—O3174.5 (6)
C2—C3—C4—C3i2.2 (4)C5—O1—C6—O27.5 (12)
C5—C3—C4—C3i175.5 (7)C5—O1—C6—C7166.4 (6)
C6—O1—C5—O396.1 (7)C5—O3—C8—O47.9 (10)
C6—O1—C5—C3142.8 (6)C5—O3—C8—C9174.6 (6)
Symmetry code: (i) x+1, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4A···O30.932.462.815 (7)103
C5—H5A···O20.982.342.693 (9)100
C7—H7C···O2ii0.962.373.318 (11)170
Symmetry code: (ii) x+3/2, y+3/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC16H16Br2O8
Mr496.09
Crystal system, space groupOrthorhombic, Pbcn
Temperature (K)298
a, b, c (Å)20.639 (4), 10.150 (2), 9.0880 (18)
V3)1903.8 (6)
Z4
Radiation typeMo Kα
µ (mm1)4.30
Crystal size (mm)0.40 × 0.30 × 0.20
Data collection
DiffractometerEnraf–Nonius CAD-4
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.278, 0.480
No. of measured, independent and
observed [I > 2σ(I)] reflections
3687, 1877, 805
Rint0.054
(sin θ/λ)max1)0.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.067, 0.130, 0.96
No. of reflections1877
No. of parameters107
No. of restraints29
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.58, 0.49

Computer programs: CAD-4 Software (Enraf–Nonius, 1985), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 2000).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C4—H4A···O30.93002.46002.815 (7)103.00
C5—H5A···O20.98002.34002.693 (9)100.00
C7—H7C···O2i0.96002.37003.318 (11)170.00
Symmetry code: (i) x+3/2, y+3/2, z+1/2.
 

Acknowledgements

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

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.  CSD CrossRef Web of Science Google Scholar
First citationBruker (2000). SHELXTL. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationEnraf–Nonius (1985). CAD-4 Software. Version 5.0. Enraf–Nonius, Delft, The Netherlands.  Google Scholar
First citationHarms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.  Google Scholar
First citationMitchell, R. H., Iyer, V. S., Khalifa, N., Mahadevan, R., Venugopalan, S., Weerawarna, S. A. & Zhou, P. Z. (1995). J. Am. Chem. Soc. 117, 1514–1532.  CSD CrossRef CAS Web of Science Google Scholar
First citationNorth, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.  CrossRef IUCr Journals Web of Science Google Scholar
First citationSheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.  Google Scholar

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ISSN: 2056-9890
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