rac-(1R,2R,4S)-1,2-Dibromo-4-[(1R)-1,2-dibromo-eth-yl]cyclo-hexa-ne.

In the title compound, C(8)H(12)Br(4), the cyclo-hexane 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 inter-molecular 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 ▶; de Wit et al., 2010 ▶), 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 ▶; Gauthier et al., 2009 ▶). 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 ▶; Muir et al., 2007 ▶; Khalaf et al., 2009 ▶; Nyholm et al., 2009 ▶, 2010 ▶). The Br⋯Br contacts in the crystal structure can be classified according to Ramasubbu et al. (1986 ▶).

Experimental

Crystal data

C8H12Br4

M = 427.82

Monoclinic,

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 ▶) 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 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶) and ORTEPIII (Burnett & Johnson, 1996 ▶); software used to prepare material for publication: SHELXTL.

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

C8H12Br4	F(000) = 800
Mr = 427.82	Dx = 2.372 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 48 reflections
a = 9.6163 (14) Å	θ = 2.2–35°
b = 13.9193 (19) Å	µ = 13.39 mm−1
c = 9.6354 (15) Å	T = 294 K
β = 111.769 (9)°	Block, colourless
V = 1197.7 (3) Å3	0.14 × 0.11 × 0.05 mm
Z = 4

Bruker APEX CCD area-detector diffractometer	2213 independent reflections
Radiation source: fine-focus sealed tube	1471 reflections with I > 2σ(I)
graphite	Rint = 0.104
ω/2θ scans	θmax = 25.4°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −11→11
Tmin = 0.61, Tmax = 0.72	k = −16→16
20037 measured reflections	l = −11→11

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)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.086	H-atom parameters constrained
S = 1.01	w = 1/[σ2(Fo2) + (0.0411P)2] where P = (Fo2 + 2Fc2)/3
2213 reflections	(Δ/σ)max < 0.001
109 parameters	Δρmax = 0.74 e Å−3
0 restraints	Δρmin = −0.55 e Å−3

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
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)
Br3	0.29332 (7)	−0.05633 (4)	0.35758 (7)	0.0640 (2)
Br4	0.48396 (8)	0.23052 (5)	0.26547 (9)	0.0742 (2)
C1	−0.1618 (6)	0.1472 (3)	0.1927 (6)	0.0424 (13)
H1	−0.2493	0.1896	0.1612	0.051*
C2	−0.0616 (5)	0.1722 (3)	0.3510 (6)	0.0366 (12)
H2	−0.1122	0.1535	0.4184	0.044*
C3	0.0879 (5)	0.1238 (3)	0.4013 (5)	0.0377 (12)
H3A	0.0747	0.0558	0.4150	0.045*
H3B	0.1510	0.1501	0.4972	0.045*
C4	0.1672 (5)	0.1358 (3)	0.2906 (5)	0.0340 (12)
H4	0.1874	0.2045	0.2864	0.041*
C5	0.3200 (6)	0.0841 (4)	0.3478 (6)	0.0436 (13)
H5	0.3768	0.1071	0.4492	0.052*
C6	0.4170 (6)	0.0966 (4)	0.2563 (7)	0.0596 (16)
H6A	0.3606	0.0789	0.1532	0.072*
H6B	0.5033	0.0545	0.2945	0.072*
C7	0.0666 (5)	0.1057 (4)	0.1343 (5)	0.0434 (13)
H7A	0.1158	0.1201	0.0652	0.052*
H7B	0.0502	0.0369	0.1325	0.052*
C8	−0.0828 (6)	0.1569 (4)	0.0840 (6)	0.0450 (14)
H8A	−0.0671	0.2245	0.0705	0.054*
H8B	−0.1469	0.1312	−0.0120	0.054*

	U11	U22	U33	U12	U13	U23
Br1	0.0576 (4)	0.0503 (3)	0.0783 (5)	−0.0152 (3)	0.0285 (4)	−0.0085 (3)
Br2	0.0605 (4)	0.0369 (3)	0.0721 (5)	0.0061 (3)	0.0240 (4)	−0.0052 (3)
Br3	0.0600 (4)	0.0451 (3)	0.0740 (5)	0.0157 (3)	0.0100 (4)	−0.0049 (3)
Br4	0.0771 (5)	0.0802 (5)	0.0861 (6)	−0.0076 (4)	0.0545 (4)	−0.0118 (4)
C1	0.040 (3)	0.038 (3)	0.050 (4)	0.006 (2)	0.018 (3)	0.007 (2)
C2	0.036 (3)	0.037 (3)	0.040 (3)	0.003 (2)	0.018 (3)	0.001 (2)
C3	0.041 (3)	0.043 (3)	0.025 (3)	0.005 (2)	0.008 (3)	−0.001 (2)
C4	0.032 (3)	0.035 (3)	0.030 (3)	0.001 (2)	0.006 (2)	−0.004 (2)
C5	0.035 (3)	0.047 (3)	0.045 (4)	0.003 (2)	0.010 (3)	−0.011 (3)
C6	0.048 (4)	0.067 (4)	0.066 (4)	0.001 (3)	0.025 (3)	−0.023 (3)
C7	0.036 (3)	0.061 (3)	0.032 (3)	0.011 (3)	0.011 (3)	0.003 (3)
C8	0.042 (3)	0.056 (3)	0.034 (3)	0.004 (3)	0.010 (3)	0.005 (3)

Br1—C1	1.980 (5)	C4—C7	1.516 (7)
Br2—C2	1.985 (5)	C4—C5	1.543 (7)
Br3—C5	1.979 (5)	C4—H4	0.9800
Br4—C6	1.964 (6)	C5—C6	1.512 (7)
C1—C8	1.511 (7)	C5—H5	0.9800
C1—C2	1.512 (7)	C6—H6A	0.9700
C1—H1	0.9800	C6—H6B	0.9700
C2—C3	1.496 (6)	C7—C8	1.513 (7)
C2—H2	0.9800	C7—H7A	0.9700
C3—C4	1.533 (7)	C7—H7B	0.9700
C3—H3A	0.9700	C8—H8A	0.9700
C3—H3B	0.9700	C8—H8B	0.9700
C8—C1—C2	112.5 (4)	C6—C5—C4	116.8 (5)
C8—C1—Br1	109.7 (3)	C6—C5—Br3	105.1 (3)
C2—C1—Br1	107.5 (3)	C4—C5—Br3	110.8 (3)
C8—C1—H1	109.0	C6—C5—H5	108.0
C2—C1—H1	109.0	C4—C5—H5	108.0
Br1—C1—H1	109.0	Br3—C5—H5	108.0
C3—C2—C1	113.5 (4)	C5—C6—Br4	110.2 (4)
C3—C2—Br2	111.2 (3)	C5—C6—H6A	109.6
C1—C2—Br2	106.1 (3)	Br4—C6—H6A	109.6
C3—C2—H2	108.7	C5—C6—H6B	109.6
C1—C2—H2	108.7	Br4—C6—H6B	109.6
Br2—C2—H2	108.7	H6A—C6—H6B	108.1
C2—C3—C4	113.1 (4)	C8—C7—C4	111.6 (4)
C2—C3—H3A	109.0	C8—C7—H7A	109.3
C4—C3—H3A	109.0	C4—C7—H7A	109.3
C2—C3—H3B	109.0	C8—C7—H7B	109.3
C4—C3—H3B	109.0	C4—C7—H7B	109.3
H3A—C3—H3B	107.8	H7A—C7—H7B	108.0
C7—C4—C3	111.2 (4)	C1—C8—C7	113.4 (4)
C7—C4—C5	113.5 (4)	C1—C8—H8A	108.9
C3—C4—C5	110.8 (4)	C7—C8—H8A	108.9
C7—C4—H4	107.0	C1—C8—H8B	108.9
C3—C4—H4	107.0	C7—C8—H8B	108.9
C5—C4—H4	107.0	H8A—C8—H8B	107.7
C8—C1—C2—C3	−48.8 (6)	C7—C4—C5—Br3	−61.2 (5)
Br1—C1—C2—C3	72.1 (4)	C3—C4—C5—Br3	64.7 (4)
C8—C1—C2—Br2	73.5 (4)	C4—C5—C6—Br4	66.9 (5)
Br1—C1—C2—Br2	−165.6 (2)	Br3—C5—C6—Br4	−170.0 (3)
C1—C2—C3—C4	50.4 (6)	C3—C4—C7—C8	53.3 (5)
Br2—C2—C3—C4	−69.1 (5)	C5—C4—C7—C8	179.0 (4)
C2—C3—C4—C7	−52.6 (5)	C2—C1—C8—C7	50.4 (6)
C2—C3—C4—C5	−179.7 (4)	Br1—C1—C8—C7	−69.2 (5)
C7—C4—C5—C6	59.0 (6)	C4—C7—C8—C1	−53.2 (6)
C3—C4—C5—C6	−175.1 (4)