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Acta Crystallogr Sect E Struct Rep Online. 2010 December 1; 66(Pt 12): o3318.
Published online 2010 November 27. doi:  10.1107/S160053681004763X
PMCID: PMC3011632

rac-(1R,2R,4S)-1,2-Dibromo-4-[(1R)-1,2-dibromo­eth­yl]cyclo­hexa­ne

Abstract

In the title compound, C8H12Br4, the cyclo­hexane ring exhibits a chair conformation. The C—Br distances range from 1.964 (6) to 1.985 (5) Å and the C—C distances range from 1.496 (6) to 1.543 (7) Å. Short inter­molecular Br(...)Br contacts [3.467 (4) Å] occur in the crystal.

Related literature

The title compound is an environmentally novel brominated flame retardant (Arsenault et al., 2008 [triangle]; de Wit et al., 2010 [triangle]), also known as TBECH, which was recently identified in beluga whales and in the eggs of herring gulls and double-crested cormorants (Tomy et al., 2008 [triangle]; Gauthier et al., 2009 [triangle]). There is relatively little information available concerning the persistence of TBECH in environmental media, its bioaccumulation in food webs and the toxicity of the pure stereoisomers (Rattfelt et al., 2006 [triangle]; Muir et al., 2007 [triangle]; Khalaf et al., 2009 [triangle]; Nyholm et al., 2009 [triangle], 2010 [triangle]). The Br(...)Br contacts in the crystal structure can be classified according to Ramasubbu et al. (1986 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-o3318-scheme1.jpg

Experimental

Crystal data

  • C8H12Br4
  • M r = 427.82
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o3318-efi1.jpg
  • a = 9.6163 (14) Å
  • b = 13.9193 (19) Å
  • c = 9.6354 (15) Å
  • β = 111.769 (9)°
  • V = 1197.7 (3) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 13.39 mm−1
  • T = 294 K
  • 0.14 × 0.11 × 0.05 mm

Data collection

  • Bruker APEX CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2001 [triangle]) T min = 0.61, T max = 0.72
  • 20037 measured reflections
  • 2213 independent reflections
  • 1471 reflections with I > 2σ(I)
  • R int = 0.104

Refinement

  • R[F 2 > 2σ(F 2)] = 0.032
  • wR(F 2) = 0.086
  • S = 1.01
  • 2213 reflections
  • 109 parameters
  • H-atom parameters constrained
  • Δρmax = 0.74 e Å−3
  • Δρmin = −0.55 e Å−3

Data collection: SMART (Bruker, 2001 [triangle]); cell refinement: SAINT (Bruker, 2001 [triangle]); data reduction: SAINT; 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]) and ORTEPIII (Burnett & Johnson, 1996 [triangle]); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053681004763X/sj5056sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053681004763X/sj5056Isup2.hkl

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

supplementary crystallographic information

Comment

1,2-Dibromo-4-(1,2-dibromoethyl)cyclohexane, also known as tetrabromoethylcyclohexane (TBECH), is a cycloaliphatic brominated flame retardant used as an additive to flammable materials (e.g., polystyrene and polyurethane) to decrease the risk of accidental fire (Arsenault et al. 2008, Tomy et al. 2008, de Wit et al. 2010). Due to the presence of 4 chiral carbons (C1, C2, C4, C5) TBECH can exist as four diastereomeric pairs of enantiomers (Arsenault et al. 2008). The structural differences between these stereoisomers lead to concomitant variability in physicochemical properties such as hydrophobicity and water solubility, resulting in variable propensities for biological uptake and metabolism. In this respect, the complex stereoisomerism of TBECH is a challenge for its trace quantification in relevant environmental matrices and in the food chain. Recently TBECH has been found to bioaccumulate in fish after dietary exposure (Rattfelt et al. 2006, Nyholm et al. 2009) and it was identified as a possible persistent, bioaccumulative and endocrine disrupting organohalogen chemical (Muir et al. 2007, Khalaf et al. 2009). Calculated half-lives of technical TBECH in activated aerobic and anaerobic soil at 20 °C were estimated to be 21 and 23 days, respectively (Nyholm et al. 2010). In the same study much slower degradation was observed during incubation at 8 °C (half-life: 120 days), suggesting that TBECH will persist in temperate climate zones for an extended period. However, the findings of TBECH in a maritime species (beluga whale) (Tomy et al. 2008) as well as seabirds (herring gulls and double-crested cormorants) (Gauthier et al. 2009) were reported for the first time.

The molecular structure of the compound and the atom-labeling scheme are shown in Fig 1. The compound crystallises as a racemate. and each molecule is involved in two intermolecular Br···Br contacts [d(Br1-Br2): 3.467 (4)Å] below the sum of their van der Waals radii, which influence the molecular packing and lead to the formation of chains along the b axis. Generally, halogen···halogen contacts C—X···X—C are defined as type I if the C—X···X angle θ1 is equal or nearly equal to the X···X—C angle θ2. If σimeq 180° and σimeq 90°, the contact is defined as type II (Ramasubbu et al. 1986). For the title compound the respective values amount to θ1(C1—Br1···Br2) = 161.2 (2)° and θ1(C2—Br2···Br1) = 137.3 (2)° These values are in acoordance with type I contacts arise as a result of close packing about an inversion center.

Experimental

In a 2 L two-necked round bottom flask equipped with a thermometer and a 50 ml dropping funnel, 20.1 g (186 mmol) 4-vinylcyclohexene were dissolved in 1000 mL of dichloromethane. Bromine (19.5 ml, 381 mmol) was slowly added through the dropping funnel within 60 min. Light was excluded from the flask and the reaction mixture was stirred for 20 hrs at ambient temperature. Then excess bromine and dichloromethane were removed by rotary evaporation and the white residue was recrystallied from methanol. For single-crystal x-ray crystallography colourless crystals of the title compound were grown by slow solvent evaporation from methanol at ambient temperature in the absence of light.

Refinement

The C—H hydrogen atoms were located in difference maps and and fixed in their found positions with Uiso(H) = 1.2 of the parent atom Ueq or 1.5 Ueq(Cmethyl).

Figures

Fig. 1.
ORTEP representation of the title compound with atomic labeling shown with 30% probability displacement ellipsoids.
Fig. 2.
View of the unit cell of the title compound along [001] (Br: red spheres, C: gray spheres, H: light gray spheres). Short Br···Br contacts are drawn as dashed red lines.

Crystal data

C8H12Br4F(000) = 800
Mr = 427.82Dx = 2.372 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 48 reflections
a = 9.6163 (14) Åθ = 2.2–35°
b = 13.9193 (19) ŵ = 13.39 mm1
c = 9.6354 (15) ÅT = 294 K
β = 111.769 (9)°Block, colourless
V = 1197.7 (3) Å30.14 × 0.11 × 0.05 mm
Z = 4

Data collection

Bruker APEX CCD area-detector diffractometer2213 independent reflections
Radiation source: fine-focus sealed tube1471 reflections with I > 2σ(I)
graphiteRint = 0.104
ω/2θ scansθmax = 25.4°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Bruker, 2001)h = −11→11
Tmin = 0.61, Tmax = 0.72k = −16→16
20037 measured reflectionsl = −11→11

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)] = 0.032Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.086H-atom parameters constrained
S = 1.01w = 1/[σ2(Fo2) + (0.0411P)2] where P = (Fo2 + 2Fc2)/3
2213 reflections(Δ/σ)max < 0.001
109 parametersΔρmax = 0.74 e Å3
0 restraintsΔρmin = −0.55 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
Br1−0.22923 (7)0.01287 (4)0.19367 (7)0.0611 (2)
Br2−0.03998 (7)0.31412 (4)0.35632 (7)0.0567 (2)
Br30.29332 (7)−0.05633 (4)0.35758 (7)0.0640 (2)
Br40.48396 (8)0.23052 (5)0.26547 (9)0.0742 (2)
C1−0.1618 (6)0.1472 (3)0.1927 (6)0.0424 (13)
H1−0.24930.18960.16120.051*
C2−0.0616 (5)0.1722 (3)0.3510 (6)0.0366 (12)
H2−0.11220.15350.41840.044*
C30.0879 (5)0.1238 (3)0.4013 (5)0.0377 (12)
H3A0.07470.05580.41500.045*
H3B0.15100.15010.49720.045*
C40.1672 (5)0.1358 (3)0.2906 (5)0.0340 (12)
H40.18740.20450.28640.041*
C50.3200 (6)0.0841 (4)0.3478 (6)0.0436 (13)
H50.37680.10710.44920.052*
C60.4170 (6)0.0966 (4)0.2563 (7)0.0596 (16)
H6A0.36060.07890.15320.072*
H6B0.50330.05450.29450.072*
C70.0666 (5)0.1057 (4)0.1343 (5)0.0434 (13)
H7A0.11580.12010.06520.052*
H7B0.05020.03690.13250.052*
C8−0.0828 (6)0.1569 (4)0.0840 (6)0.0450 (14)
H8A−0.06710.22450.07050.054*
H8B−0.14690.1312−0.01200.054*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Br10.0576 (4)0.0503 (3)0.0783 (5)−0.0152 (3)0.0285 (4)−0.0085 (3)
Br20.0605 (4)0.0369 (3)0.0721 (5)0.0061 (3)0.0240 (4)−0.0052 (3)
Br30.0600 (4)0.0451 (3)0.0740 (5)0.0157 (3)0.0100 (4)−0.0049 (3)
Br40.0771 (5)0.0802 (5)0.0861 (6)−0.0076 (4)0.0545 (4)−0.0118 (4)
C10.040 (3)0.038 (3)0.050 (4)0.006 (2)0.018 (3)0.007 (2)
C20.036 (3)0.037 (3)0.040 (3)0.003 (2)0.018 (3)0.001 (2)
C30.041 (3)0.043 (3)0.025 (3)0.005 (2)0.008 (3)−0.001 (2)
C40.032 (3)0.035 (3)0.030 (3)0.001 (2)0.006 (2)−0.004 (2)
C50.035 (3)0.047 (3)0.045 (4)0.003 (2)0.010 (3)−0.011 (3)
C60.048 (4)0.067 (4)0.066 (4)0.001 (3)0.025 (3)−0.023 (3)
C70.036 (3)0.061 (3)0.032 (3)0.011 (3)0.011 (3)0.003 (3)
C80.042 (3)0.056 (3)0.034 (3)0.004 (3)0.010 (3)0.005 (3)

Geometric parameters (Å, °)

Br1—C11.980 (5)C4—C71.516 (7)
Br2—C21.985 (5)C4—C51.543 (7)
Br3—C51.979 (5)C4—H40.9800
Br4—C61.964 (6)C5—C61.512 (7)
C1—C81.511 (7)C5—H50.9800
C1—C21.512 (7)C6—H6A0.9700
C1—H10.9800C6—H6B0.9700
C2—C31.496 (6)C7—C81.513 (7)
C2—H20.9800C7—H7A0.9700
C3—C41.533 (7)C7—H7B0.9700
C3—H3A0.9700C8—H8A0.9700
C3—H3B0.9700C8—H8B0.9700
C8—C1—C2112.5 (4)C6—C5—C4116.8 (5)
C8—C1—Br1109.7 (3)C6—C5—Br3105.1 (3)
C2—C1—Br1107.5 (3)C4—C5—Br3110.8 (3)
C8—C1—H1109.0C6—C5—H5108.0
C2—C1—H1109.0C4—C5—H5108.0
Br1—C1—H1109.0Br3—C5—H5108.0
C3—C2—C1113.5 (4)C5—C6—Br4110.2 (4)
C3—C2—Br2111.2 (3)C5—C6—H6A109.6
C1—C2—Br2106.1 (3)Br4—C6—H6A109.6
C3—C2—H2108.7C5—C6—H6B109.6
C1—C2—H2108.7Br4—C6—H6B109.6
Br2—C2—H2108.7H6A—C6—H6B108.1
C2—C3—C4113.1 (4)C8—C7—C4111.6 (4)
C2—C3—H3A109.0C8—C7—H7A109.3
C4—C3—H3A109.0C4—C7—H7A109.3
C2—C3—H3B109.0C8—C7—H7B109.3
C4—C3—H3B109.0C4—C7—H7B109.3
H3A—C3—H3B107.8H7A—C7—H7B108.0
C7—C4—C3111.2 (4)C1—C8—C7113.4 (4)
C7—C4—C5113.5 (4)C1—C8—H8A108.9
C3—C4—C5110.8 (4)C7—C8—H8A108.9
C7—C4—H4107.0C1—C8—H8B108.9
C3—C4—H4107.0C7—C8—H8B108.9
C5—C4—H4107.0H8A—C8—H8B107.7
C8—C1—C2—C3−48.8 (6)C7—C4—C5—Br3−61.2 (5)
Br1—C1—C2—C372.1 (4)C3—C4—C5—Br364.7 (4)
C8—C1—C2—Br273.5 (4)C4—C5—C6—Br466.9 (5)
Br1—C1—C2—Br2−165.6 (2)Br3—C5—C6—Br4−170.0 (3)
C1—C2—C3—C450.4 (6)C3—C4—C7—C853.3 (5)
Br2—C2—C3—C4−69.1 (5)C5—C4—C7—C8179.0 (4)
C2—C3—C4—C7−52.6 (5)C2—C1—C8—C750.4 (6)
C2—C3—C4—C5−179.7 (4)Br1—C1—C8—C7−69.2 (5)
C7—C4—C5—C659.0 (6)C4—C7—C8—C1−53.2 (6)
C3—C4—C5—C6−175.1 (4)

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SJ5056).

References

  • Arsenault, G., Lough, A., Marvin, C., McAlees, A., McCrindle, R., MacInnis, G., Pleskach, K., Potter, D., Riddell, N., Sverko, E., Tittlemier, S. & Tomy, G. (2008). Chemosphere, 72, 1163–1170. [PubMed]
  • Bruker (2001). SMART, SAINT and SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Burnett, M. N. & Johnson, C. K. (1996). ORTEPIII Report ORNL-6895. Oak Ridge National Laboratory, Tennessee, USA.
  • Gauthier, L. T., Potter, D., Hebert, C. E. & Letcher, R. J. (2009). Environ. Sci. Technol 43, 312-317. [PubMed]
  • Khalaf, H., Larsson, A., Berg, H., McCrindle, R., Arsenault, G. & Olsson, P. E. (2009). Environ. Health. Persp.117, 1853–1859. [PMC free article] [PubMed]
  • Muir, D., Howard, P. H. & Meylan, W. (2007). Organohalogen Compd, 69, 1053–1056.
  • Nyholm, J. R., Lundberg, C. & Andersson, P. L. (2010). Environ. Pollut.158, 2235–2240. [PubMed]
  • Nyholm, J. R., Norman, A., Norrgren, L., Haglund, P. & Andersson, P. L. (2009). Environ. Toxicol. Chem.28, 1035–1042. [PubMed]
  • Ramasubbu, N., Parthasarathy, R. & Murrayrust, P. (1986). J. Am. Chem. Soc.108, 4308–4314.
  • Rattfelt, J., Norman, A., Norrgren, L., Haglund, P. & Andersson, P. L. (2006). Organohalogen Compd, 68, 2007–2010.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Tomy, G., Pleskach, K., Arsenault, G., Potter, D., McCrindle, R., Marvin, C., Sverko, E. & Tittlemier, S. (2008). Environ. Sci. Technol.42, 543–549. [PubMed]
  • Wit, C. A. de, Herzke, D. & Vorkamp, K. (2010). Sci. Total Environ.408, 2885–2918. [PubMed]

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