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The title compound, C12H4Br6O, belongs to a group of flame retardants known as polybrominated di­phenyl ethers (PBDE). Intermolecular Br...Br contacts in the bc plane give a sheet-like character to the structure of the title compound.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536802016926/cv6147sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536802016926/cv6147Isup2.hkl
Contains datablock I

CCDC reference: 198974

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.015 Å
  • R factor = 0.065
  • wR factor = 0.092
  • Data-to-parameter ratio = 16.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
RADNW_01 Alert C The radiation wavelength lies outside the expected range for the supplied radiation type. Expected range 1.54175-1.54180 Wavelength given = 1.54184
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
1 Alert Level C = Please check

Comment top

The polybrominated diphenyl ethers (PBDE) are one of the most important group of flame retardants. Most of the commercially available mixtures consists of highly brominated congeners, such as decabromodiphenyl ether (Eriksson et al., 1999; Mrse et al., 2000). The lower brominated PBDE's are to a large extent formed as decomposition products in the environment. Different decomposition pathways are presently examined as part of a long-term project aimed at modelling the reactivity of different PBDEs often found deposited on soot particles etc. in the environment. Theoretical calculations require accurate geometries of the molecular species involved, thus the use of geometric data derived from crystallographic measurements are invaluable.

The monobrominated ring (C1–C6) of the title compound, (I), is planar, with an r.m.s. deviation of 0.017 Å and the O atom deviating by 0.055 (18) Å and the Br1 atom deviating by 0.042 (17) Å from the ring plane. The pentabrominated ring (C7–C12) is planar, with an r.m.s. deviation of 0.015 Å and the O deviating by 0.127 (16) Å, atom Br3 deviating by 0.089 (16) Å and atom Br4 deviating by 0.070 (15) Å from the ring plane. The rest of the Br atoms, viz. Br2, Br5 and Br6, are coplanar with this ring. The dihedral angle between the two ring planes is 89.6 (3)°.

A view along the b axis, of the arrangement of the molecules of the title compound, (I), is shown in Fig. 2, where the three shortest intermolecular Br···Br contacts are marked. These contacts are: Br1···Br2i = 3.612 (2) Å, Br3···Br3ii = 3.604 (3) Å and Br4···Br5iii = 3.707 (2) Å [symmetry codes: (i) 1/2 − x, 1/2 + y, 3/2 − z; (ii) −x, 1 − y, 1 − z; (iii) −x, 2 − y, 2 − z]. Including all Br···Br contacts less than or equal to 3.9 Å in Fig. 3 illustrates the extensive intermolecular Br···Br contacts present in the bc plane. Similar to the structure of 2,3,4,5,6-pentabromophenyl phenyl ether (Eriksson & Hu, 2002), in which there are no Br substituents on one of the rings, the title compound forms sheets defined by the Br···Br contacts, at x 0.0 and 1/2, with small cavities where the monobrominated ring of molecules from neighbouring layers may fit.

Experimental top

The synthesis of the title PBDE was carried out by coupling of the decabromodiphenyl iodonium salt with a 4-bromophenylate (Beringer et al., 1959; Ziegler & Marr, 1962; Hu, 1996, 1999). The title compound was recrystallized from methanol.

Refinement top

The rather high internal R value of 0.096 results from the large amount of weak insignificant reflections. With reflections fulfilling I 2σ(I) the internal R value decreases to 0.0473.

Computing details top

Data collection: DIF4 (Stoe & Cie, 1988); cell refinement: DIF4; data reduction: X-RED (Stoe & Cie, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Bergerhoff, 1996).

Figures top
[Figure 1] Fig. 1. One molecule of the title compound with the atom-numbering scheme. Displacement ellipsoids are shown at the 50% probability level. H atoms are shown as small circles of arbitrary radii.
[Figure 2] Fig. 2. View of the packing along the b direction, with the three shortest Br···Br contacts indicated by thick dashed bonds.
[Figure 3] Fig. 3. Stereoview of the packing along the b direction, with all Br···Br contacts less than or equal to 3.9 Å indicated by thick dashed lines.
4-Bromophenyl 2,3,4,5,6-pentabromophenyl ether top
Crystal data top
C12H4Br6OF(000) = 1176
Mr = 643.61Dx = 2.804 Mg m3
Monoclinic, P21/nCu Kα radiation, λ = 1.54184 Å
Hall symbol: -P 2ynCell parameters from 46 reflections
a = 37.325 (6) Åθ = 15.4–27.1°
b = 5.2140 (6) ŵ = 18.94 mm1
c = 7.8782 (10) ÅT = 293 K
β = 96.073 (13)°Slab, colourless
V = 1524.6 (4) Å30.11 × 0.06 × 0.04 mm
Z = 4
Data collection top
Stoe AED2
diffractometer
1393 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.096
Graphite monochromatorθmax = 68.0°, θmin = 2.4°
ω–2θ scansh = 4444
Absorption correction: numerical
(X-RED; Stoe & Cie, 1997)
k = 66
Tmin = 0.13, Tmax = 0.48l = 99
8595 measured reflections4 standard reflections every 90 min
2788 independent reflections intensity decay: 1%
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)] = 0.065Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.092H-atom parameters constrained
S = 1.16 w = 1/[σ2(Fo2) + (0.01P)2]
where P = (Fo2 + 2Fc2)/3
2788 reflections(Δ/σ)max < 0.001
173 parametersΔρmax = 0.96 e Å3
61 restraintsΔρmin = 0.99 e Å3
Crystal data top
C12H4Br6OV = 1524.6 (4) Å3
Mr = 643.61Z = 4
Monoclinic, P21/nCu Kα radiation
a = 37.325 (6) ŵ = 18.94 mm1
b = 5.2140 (6) ÅT = 293 K
c = 7.8782 (10) Å0.11 × 0.06 × 0.04 mm
β = 96.073 (13)°
Data collection top
Stoe AED2
diffractometer
1393 reflections with I > 2σ(I)
Absorption correction: numerical
(X-RED; Stoe & Cie, 1997)
Rint = 0.096
Tmin = 0.13, Tmax = 0.484 standard reflections every 90 min
8595 measured reflections intensity decay: 1%
2788 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.06561 restraints
wR(F2) = 0.092H-atom parameters constrained
S = 1.16Δρmax = 0.96 e Å3
2788 reflectionsΔρmin = 0.99 e Å3
173 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
Br10.29833 (4)0.4343 (4)0.9542 (2)0.0619 (5)
Br20.11240 (4)0.0332 (3)0.6824 (2)0.0548 (4)
Br30.03976 (4)0.3222 (4)0.5780 (2)0.0616 (5)
Br40.01565 (4)0.7496 (3)0.8512 (2)0.0575 (4)
Br50.06364 (4)0.8209 (3)1.2219 (2)0.0591 (5)
Br60.13701 (4)0.4691 (4)1.3114 (2)0.0685 (5)
O0.1463 (2)0.0899 (16)1.0331 (11)0.047 (2)
C10.1812 (3)0.1848 (19)1.0155 (14)0.033 (3)
C20.1869 (3)0.400 (2)0.9220 (15)0.041 (3)
H20.16770.49790.87290.049*
C30.2227 (3)0.468 (3)0.9028 (16)0.058 (4)
H30.22700.61200.83830.069*
C40.2520 (3)0.327 (2)0.9771 (14)0.040 (3)
C50.2446 (3)0.113 (2)1.0714 (15)0.039 (3)
H50.26360.02041.12680.047*
C60.2096 (2)0.033 (2)1.0857 (15)0.040 (3)
H60.20530.11991.14110.048*
C70.1177 (3)0.256 (2)0.9888 (12)0.036 (3)
C80.0972 (3)0.212 (2)0.8339 (12)0.034 (3)
C90.0663 (3)0.362 (2)0.7944 (15)0.042 (3)
C100.0564 (3)0.547 (2)0.9074 (13)0.036 (3)
C110.0768 (3)0.575 (3)1.0648 (14)0.046 (3)
C120.1084 (3)0.435 (2)1.1069 (15)0.046 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0442 (8)0.0796 (12)0.0622 (10)0.0071 (9)0.0067 (7)0.0022 (10)
Br20.0485 (8)0.0582 (11)0.0585 (10)0.0030 (8)0.0099 (7)0.0003 (9)
Br30.0544 (9)0.0755 (13)0.0535 (10)0.0076 (9)0.0016 (8)0.0047 (10)
Br40.0469 (8)0.0613 (11)0.0634 (10)0.0075 (8)0.0022 (7)0.0078 (10)
Br50.0600 (10)0.0607 (12)0.0576 (10)0.0034 (8)0.0104 (8)0.0011 (9)
Br60.0580 (9)0.0907 (15)0.0549 (10)0.0057 (10)0.0022 (8)0.0003 (11)
O0.038 (4)0.038 (5)0.063 (6)0.001 (4)0.004 (4)0.009 (5)
C10.030 (5)0.028 (7)0.042 (7)0.002 (5)0.008 (5)0.008 (6)
C20.021 (5)0.050 (9)0.051 (8)0.007 (5)0.001 (5)0.005 (7)
C30.061 (7)0.064 (10)0.053 (9)0.004 (7)0.028 (7)0.007 (8)
C40.028 (5)0.053 (8)0.037 (7)0.002 (6)0.000 (5)0.007 (6)
C50.031 (6)0.038 (7)0.047 (8)0.006 (5)0.002 (5)0.010 (6)
C60.034 (6)0.034 (7)0.053 (8)0.003 (6)0.003 (5)0.017 (7)
C70.026 (5)0.037 (7)0.042 (6)0.001 (5)0.007 (5)0.008 (6)
C80.051 (7)0.019 (6)0.033 (6)0.010 (5)0.012 (5)0.005 (5)
C90.027 (6)0.041 (8)0.054 (8)0.001 (5)0.010 (5)0.012 (6)
C100.026 (5)0.029 (6)0.052 (7)0.000 (5)0.004 (5)0.014 (6)
C110.031 (6)0.066 (9)0.042 (7)0.006 (6)0.010 (5)0.009 (7)
C120.045 (7)0.046 (8)0.045 (7)0.002 (6)0.003 (6)0.006 (7)
Geometric parameters (Å, º) top
Br1—C41.844 (11)C4—C51.386 (9)
Br2—C81.878 (10)C5—C61.386 (8)
Br3—C91.890 (11)C7—C121.389 (9)
Br4—C101.865 (10)C7—C81.390 (9)
Br5—C111.883 (13)C8—C91.399 (8)
Br6—C121.845 (11)C9—C101.390 (9)
O—C71.391 (12)C10—C111.394 (9)
O—C11.414 (12)C11—C121.395 (9)
C1—C21.371 (9)C2—H20.9300
C1—C61.391 (8)C3—H30.9300
C2—C31.406 (9)C5—H50.9300
C3—C41.392 (9)C6—H60.9300
C7—O—C1116.7 (8)C8—C9—Br3118.7 (8)
C2—C1—C6121.7 (10)C9—C10—C11119.0 (10)
C2—C1—O122.4 (9)C9—C10—Br4120.4 (7)
C6—C1—O115.7 (9)C11—C10—Br4120.6 (8)
C1—C2—C3117.8 (10)C10—C11—C12121.8 (11)
C4—C3—C2122.3 (11)C10—C11—Br5119.9 (8)
C5—C4—C3117.2 (10)C12—C11—Br5118.2 (8)
C5—C4—Br1122.6 (8)C7—C12—C11117.3 (11)
C3—C4—Br1120.2 (8)C7—C12—Br6119.1 (8)
C4—C5—C6122.0 (10)C11—C12—Br6123.6 (8)
C5—C6—C1118.6 (10)C1—C2—H2121.1
C12—C7—C8123.0 (10)C3—C2—H2121.1
C12—C7—O119.4 (9)C4—C3—H3118.8
C8—C7—O117.1 (9)C2—C3—H3118.8
C7—C8—C9117.9 (10)C6—C5—H5119.0
C7—C8—Br2119.6 (7)C4—C5—H5119.0
C9—C8—Br2122.4 (7)C5—C6—H6120.7
C10—C9—C8120.9 (10)C1—C6—H6120.7
C10—C9—Br3120.3 (7)
C8—C7—O—C1104.2 (12)C2—C1—O—C715.7 (16)
C12—C7—O—C183.3 (14)C6—C1—O—C7170.1 (10)

Experimental details

Crystal data
Chemical formulaC12H4Br6O
Mr643.61
Crystal system, space groupMonoclinic, P21/n
Temperature (K)293
a, b, c (Å)37.325 (6), 5.2140 (6), 7.8782 (10)
β (°) 96.073 (13)
V3)1524.6 (4)
Z4
Radiation typeCu Kα
µ (mm1)18.94
Crystal size (mm)0.11 × 0.06 × 0.04
Data collection
DiffractometerStoe AED2
diffractometer
Absorption correctionNumerical
(X-RED; Stoe & Cie, 1997)
Tmin, Tmax0.13, 0.48
No. of measured, independent and
observed [I > 2σ(I)] reflections
8595, 2788, 1393
Rint0.096
(sin θ/λ)max1)0.602
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.065, 0.092, 1.16
No. of reflections2788
No. of parameters173
No. of restraints61
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.96, 0.99

Computer programs: DIF4 (Stoe & Cie, 1988), DIF4, X-RED (Stoe & Cie, 1997), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), DIAMOND (Bergerhoff, 1996).

Selected geometric parameters (Å, º) top
Br1—C41.844 (11)Br5—C111.883 (13)
Br2—C81.878 (10)Br6—C121.845 (11)
Br3—C91.890 (11)O—C71.391 (12)
Br4—C101.865 (10)O—C11.414 (12)
C7—O—C1116.7 (8)C12—C7—C8123.0 (10)
C2—C1—C6121.7 (10)C12—C7—O119.4 (9)
C2—C1—O122.4 (9)C8—C7—O117.1 (9)
C6—C1—O115.7 (9)
C8—C7—O—C1104.2 (12)C2—C1—O—C715.7 (16)
C12—C7—O—C183.3 (14)C6—C1—O—C7170.1 (10)
 

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