Phenyl 2,4,6 tri­bromo­phenyl ether

organic papers

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Acta Crystallographica Section E

Structure Reports Online

ISSN 1600-5368

Phenyl 2,4,6-tribromophenyl ether

Lars Erikssona_{* and Jiwei Hu}b

a_{Division of Structural Chemistry,} Arrhenius-laboratory, Stockholm University, S-106 91 Stockholm, Sweden, andb_{Department of} Chemistry, University of JyvaÈskylaÈ, FIN-40 351 JyvaÈskylaÈ, Finland

Correspondence e-mail: [email protected]

Key indicators

Single-crystal X-ray study

T= 293 K

Mean(C±C) = 0.006 AÊ

Rfactor = 0.033

wRfactor = 0.065

Data-to-parameter ratio = 16.7

For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.

#2001 International Union of Crystallography Printed in Great Britain ± all rights reserved

The title compound, C12H7Br3O, is the third well characterized

of a total of 209 different brominated diphenyl ethers. The bromine-substituted rings pack in the crystal in a common plane with the same ring from symmetry-related neighbouring molecules. The short Br Br contact distance [3.519 (2) AÊ], together with a pair of considerably longer Br Br contact distances [3.966 (2) AÊ], may be part of a model describing this packing.

Comment

One of the most important groups of ¯ame retardants is that of the polybrominated diphenyl ethers (PBDE). There are 209 possible brominated congeners, but most of the commercially available mixtures consist of highly brominated congeners such as decabromodiphenyl ether (Eriksson et al., 1999). Brominated diphenyl ethers are additive ¯ame retardants, which means that they are only mixed together with plastic material and therefore they migrate more easily to the environment than if they had been covalently bonded with the polymer material (Kuryla & Papa, 1979). The number of known PBDEs without any heterosubstituent, such as hydroxylsetc., is rather limited. In the autumn 2001 release of the Cambridge Structural Database (CSD; Allen & Kennard, 1993), only three PBDE's are listed and one of these without coordinates. Including hetero substituents other than bromine gives a larger set of structures for use as model compounds, but still only of the order of 10±15 structures. One salient feature of the PBDEs is that they are often not found in the environment in proportion to their use. A possible reason for this is that they are decomposed by sunlight, radicals or some other reactions in the environment (OÈrnet al., 1996). It is a long-term goal to try to model the reactivity of different PBDEs that are often found deposited on solid soot particles

etc. Thus an accurate model of the crystal structure is impor-tant.

The packing of the title compound, (I) (Fig. 1), shows some interesting features. The brominated ring (C1±C6) is planar within 0.005 AÊ, with Br1 deviating by 0.034 (6) AÊ, Br2 in the

ring plane, Br3 deviating by 0.036 (5) AÊ and the O atom deviating by 0.084 (5) AÊ from the ring plane; the other benzene ring is planar within <0.01 AÊ, also with the O atom in the plane. The angle between the ring planes is 89.8 (1)_{. The}

molecules pack in such a way that bromine-substituted rings from different molecules all occupy the same plane (Fig. 2).

The C atoms of the constituent Br-substituted rings deviate by <0.01 AÊ from the ring plane. At least one of the Br contacts, Br2 Br2(ÿx+ 2, ÿy+ 1, ÿz+ 1), is rather short at 3.519 (2) AÊ, while the next longer contact, Br3 Br1(ÿx, ÿy+ 2, ÿz+ 1), is 3.966 (2) AÊ. The ®rst of these Br Br contacts is considered short compared with similar distances from a search of all intermolecular Br Br distances in Br-substituted aromatic compounds in the CSD (Allen & Kennard, 1993), shown in Fig. 3. Whether the packing of the molecules in the crystal is an effect of the interhalogen bonding or if the short halogen contacts are consequences of the packing in the crystal is an open question.

Experimental

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

Crystal data

C12H7Br3O Mr= 406.91

Triclinic,P1

a= 5.994 (2) AÊ

b= 10.182 (5) AÊ

c= 11.479 (5) AÊ

= 109.43 (5)

= 99.76 (4)

= 97.37 (5)

V= 638.1 (3) AÊ3

Z= 2

Dx= 2.118 Mg mÿ3

MoKradiation Cell parameters from 1255

re¯ections

= 1.7±25.0

= 9.46 mmÿ1 T= 293 (2) K Irregular, colourless 0.240.150.13 mm

Data collection

Stoe IPDS diffractometer Area-detector scans

Absorption correction: numerical (X-RED; Stoe & Cie, 1997)

Tmin= 0.104,Tmax= 0.303

9866 measured re¯ections 2425 independent re¯ections

1701 re¯ections withI> 2(I)

Rint= 0.055 max= 25.9 h=ÿ7!7

k=ÿ12!12

l=ÿ14!14

Re®nement

Re®nement onF2 R[F2_{> 2(F}2_{)] = 0.033} wR(F2_{) = 0.066} S= 1.23 2425 re¯ections 145 parameters

H-atom parameters constrained

w= 1/[2_(F

o2) + (0.02P)2]

whereP= (Fo2+ 2Fc2)/3

(/)max= 0.001

max= 0.59 e AÊÿ3

min=ÿ0.38 e AÊÿ3

Table 1

Selected geometric parameters (AÊ,_).

Br1ÐC2 1.884 (4) Br2ÐC6 1.894 (4) Br3ÐC4 1.907 (4)

OÐC1 1.381 (4) OÐC7 1.394 (4) C1ÐOÐC7 117.3 (3)

OÐC1ÐC6 121.7 (4) OÐC1ÐC2 119.7 (3)

C9ÐC7ÐO 123.2 (3) C12ÐC7ÐO 115.5 (4) C7ÐOÐC1ÐC6 78.7 (4)

C7ÐOÐC1ÐC2 ÿ107.1 (4) C1ÐOÐC7ÐC9C1ÐOÐC7ÐC12 ÿ155.5 (3)26.2 (5)

Data collection: EXPOSE in IPDS Software (Stoe, 1997); cell re®nement:CELLinIPDS Software; data reduction:INTEGRATE in IPDS Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to re®ne structure:SHELXL97

Acta Cryst.(2001). E57, o930±o932 Eriksson and Hu C₁₂H₇Br₃O

o931

organic papers

Figure 1

The 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

Packing diagram of the title compound [symmetry codes: (#1)ÿx+ 2, ÿy+ 1,ÿz+ + 1; (#2)ÿx,ÿy+2,ÿz+ 1].

Figure 3

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(Sheldrick, 1997); molecular graphics: DIAMOND (Bergerhoff, 1996).

This work was supported by a grant from the Swedish Natural Science Research Council.

References

Allen, F. H. & Kennard, O. (1993).Chem. Des. Autom. News,8, 1, 31±37. Bergerhoff, G. (1996).DIAMOND. Gerhard-Domagk-Straûe 1, 53121 Bonn,

Germany.

Beringer, F. M., Falk, R. A., Karniol, M., Lillien, G., Masullo, M., Mausner, M. & Sommer, E. (1959).J. Am. Chem. Soc.81, 342±351.

Eriksson, J., Eriksson, L. & Jakobsson, E. (1999).Acta Cryst.C55, 2169±2171.

Hu, J. (1996). Polybrominated Diphenyl Ethers (PBDE) Synthesis and Characterization. Licenciate Thesis, Department of Environmental Chem-istry, Stockholm University, Sweden.

Hu, J. (1999).Peristent Polyhalogenated Diphenyl Ethers: Model Compound Syntheses, Characterization and Molecular Orbital Studies. Doctorate Thesis, Department of Chemistry, Research Report No. 73, University of JyvaÈskylaÈ, Finland.

Kuryla, W. C. & Papa, A. J. (1979).Flame Retardancy of Polymeric Materials, Vol. 5. New York: Dekker.

OÈrn, U., Eriksson, L., Jakobsson, E. & Bergman, AÊ (1996).Acta Chem. Scand.

50, 802±807.

Sheldrick, G. M. (1990).Acta Cryst.A46, 467±473.

Sheldrick, G. M. (1997).SHELXL97. University of GoÈttingen, Germany. Stoe & Cie (1997).IPDS Software(Version 2.87, December 1997) andX-RED

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supporting information

Acta Cryst. (2001). E57, o930–o932 [doi:10.1107/S1600536801014702]

Phenyl 2,4,6-tribromophenyl ether

Lars Eriksson and Jiwei Hu

S1. Comment

One of the most important group of flame retardants are the polybrominated diphenyl ethers (PBDE). There are 209

possible brominated congeners, but most of the commercially available mixtures consists of highly brominated congeners

such as decabromodiphenyl ether (Eriksson et al., 1999). Brominated diphenyl ethers are additive flame retardents, which

means that they are only mixed together with the plastic material and therefore they migrate more easily to the

environment than if they had been covalently bonded with the polymer material (Kuryla & Papa, 1979). The number of

known PBDEs without any heterosubstituent as hydroxyls etc. are rather limited. In the autumn 2001 release of the

Cambridge Structural Database (CSD; Allen & Kennard, 1993), only three PBDE's are listed and one of these without

coordinates. Including other hetero substituents than bromine gives a larger set of structures for use as model compounds,

but still only in the order of 10–15 structures. One salient feature of the PBDEs is that they are often not found in the

environment to the same extent as used. A possible reason for this is that they are decomposed by sunlight, radicals or

some other reactions in the environment (Örn et al., 1996). It is a long-term goal to try to model the reactivity of different

PBDEs that are often found deposited on solid soot particles etc. Thus an accurate model of the crystal structure are

important.

The packing of the title compound, (I), shows some interesting features. The brominated ring (C1—C6) is planar within

0.005 Å, with Br1 deviating by 0.034 (6) Å, Br2 within the ring plane, Br3 deviating by 0.036 (5) Å and the O atom

deviating by 0.084 (5) Å from the ring plane; the other benzene ring is planar within <0.01 Å, also with the O atom in the

plane. The angle between the ring planes is 89.8 (1)°. The molecules pack in a way that bromine-substituted rings from

different molecules all occupy the same plane (Fig. 2). The C atoms of the constituent Br-substituted rings deviate by

<0.01 Å from the ring plane. At least one of the Br contacts, Br2···Br2(-x + 2,-y + 1,-z + 1), is rather short at 3.519 (2) Å,

while the next longest contact, Br3···Br1(-x,-y + 2,-z + 1), is 3.966 (2) Å. The first of these Br···Br contacts is considered

short compared with similar distances from a search of all intermolecular Br···Br distances in Br-substituted aromatic

compounds in the CSD (Allen & Kennard, 1993), shown in Fig. 3. Whether the packing of the molecules in the crystal is

an effect of the interhalogen bonding or if the short halogen contacts are consequences of the packing in the crystal is an

open question.

S2. Experimental

The synthesis of the title PBDE was carried out by coupling the diphenyliodonium salt with a bromophenylate (Beringer

supporting information

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Figure 1

The 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

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Figure 3

Histogram of intermolecular Br···Br distances where the Br substitutes an aromatic ring. Data are from the CSD autumn

2001 release (Allen & Kennard, 1993).

Phenyl 2,4,6-tribromophenyl ether

Crystal data C12H7Br3O

Mr = 406.91

Triclinic, P1 a = 5.994 (2) Å b = 10.182 (5) Å c = 11.479 (5) Å α = 109.43 (5)° β = 99.76 (4)° γ = 97.37 (5)° V = 638.1 (3) Å3

Z = 2 F(000) = 384 Dx = 2.118 Mg m−3

Mo Kα radiation, λ = 0.71073 Å Cell parameters from 1255 reflections θ = 1.7–25.0°

µ = 9.46 mm−1

T = 293 K

Irregular, colourless 0.24 × 0.15 × 0.13 mm

Data collection Stoe IPDS

diffractometer

Radiation source: fine-focus sealed tube Graphite monochromator

Detector resolution: 6.0 pixels mm-1

area–detector scans

Absorption correction: numerical (X-RED; Stoe & Cie, 1997) Tmin = 0.104, Tmax = 0.303

9866 measured reflections 2425 independent reflections 1701 reflections with I > 2σ(I) Rint = 0.055

θmax = 25.9°, θmin = 3.4°

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Refinement Refinement on F2

Least-squares matrix: full R[F2 _{> 2σ(F}2_{)] = 0.033}

wR(F2_{) = 0.066}

S = 1.23 2425 reflections 145 parameters 0 restraints

Primary atom site location: structure-invariant direct methods

Secondary atom site location: difference Fourier map

Hydrogen site location: inferred from neighbouring sites

H-atom parameters constrained w = 1/[σ2_(F

o2) + (0.02P)2]

where P = (Fo2 + 2Fc2)/3

(Δ/σ)max = 0.001

Δρmax = 0.59 e Å−3

Δρmin = −0.38 e Å−3

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 F}2_,

conventional R-factors R are based

on F, with F set to zero for negative F2_{. The threshold expression of}

F2 _{> σ(F}2_{) 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₎

x y z Uiso*/Ueq

Br1 0.07262 (9) 0.73606 (6) 0.15501 (4) 0.08616 (19)

Br2 0.77796 (8) 0.57412 (5) 0.44077 (4) 0.07397 (16)

Br3 0.28026 (9) 0.97473 (5) 0.68889 (4) 0.07956 (18)

O 0.4696 (5) 0.5877 (3) 0.2044 (2) 0.0617 (7)

C1 0.4208 (7) 0.6706 (4) 0.3159 (3) 0.0513 (9)

C2 0.2538 (7) 0.7518 (4) 0.3119 (3) 0.0558 (10)

C3 0.2126 (7) 0.8431 (4) 0.4224 (3) 0.0622 (10)

H3 0.1000 0.8976 0.4195 0.075*

C4 0.3426 (7) 0.8514 (4) 0.5372 (3) 0.0563 (10)

C5 0.5095 (7) 0.7737 (4) 0.5446 (3) 0.0566 (10)

H5 0.5949 0.7805 0.6228 0.068*

C6 0.5486 (6) 0.6846 (4) 0.4330 (3) 0.0520 (9)

C7 0.3932 (7) 0.4412 (4) 0.1640 (3) 0.0528 (10)

C8 0.1430 (9) 0.2331 (5) 0.1495 (4) 0.0745 (12)

H8 0.0165 0.1901 0.1699 0.089*

C9 0.2065 (8) 0.3802 (4) 0.1957 (3) 0.0610 (11)

H9 0.1241 0.4362 0.2471 0.073*

C10 0.2649 (10) 0.1507 (5) 0.0742 (4) 0.0842 (15)

H10 0.2232 0.0521 0.0450 0.101*

C11 0.4488 (10) 0.2142 (6) 0.0422 (4) 0.0856 (15)

H11 0.5300 0.1580 −0.0100 0.103*

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H12 0.6390 0.4020 0.0635 0.081*

Atomic displacement parameters (Å2₎

U11 _U22 _U33 _U12 _U13 _U23

Br1 0.0885 (4) 0.1222 (4) 0.0522 (2) 0.0472 (3) 0.0070 (2) 0.0321 (2)

Br2 0.0660 (3) 0.0895 (3) 0.0816 (3) 0.0366 (2) 0.0182 (2) 0.0420 (2)

Br3 0.1070 (4) 0.0740 (3) 0.0548 (2) 0.0298 (3) 0.0220 (2) 0.0135 (2)

O 0.076 (2) 0.0645 (17) 0.0588 (14) 0.0225 (14) 0.0345 (14) 0.0280 (13)

C1 0.057 (3) 0.051 (2) 0.0513 (19) 0.0105 (18) 0.0153 (17) 0.0234 (16)

C2 0.060 (3) 0.063 (2) 0.0479 (18) 0.0191 (19) 0.0093 (17) 0.0238 (17)

C3 0.069 (3) 0.066 (2) 0.059 (2) 0.028 (2) 0.0152 (19) 0.0248 (19)

C4 0.066 (3) 0.047 (2) 0.052 (2) 0.0110 (19) 0.0148 (19) 0.0124 (16)

C5 0.065 (3) 0.051 (2) 0.0488 (19) 0.0068 (19) 0.0033 (18) 0.0176 (17)

C6 0.047 (2) 0.053 (2) 0.066 (2) 0.0131 (17) 0.0138 (18) 0.0313 (18)

C7 0.059 (3) 0.065 (3) 0.0409 (17) 0.021 (2) 0.0109 (17) 0.0241 (17)

C8 0.075 (3) 0.076 (3) 0.064 (2) −0.001 (2) 0.004 (2) 0.027 (2)

C9 0.067 (3) 0.065 (3) 0.0482 (19) 0.017 (2) 0.0126 (19) 0.0154 (18)

C10 0.095 (4) 0.067 (3) 0.067 (3) 0.017 (3) −0.011 (3) 0.008 (2)

C11 0.085 (4) 0.088 (4) 0.065 (3) 0.041 (3) 0.003 (3) 0.001 (2)

C12 0.068 (3) 0.082 (3) 0.053 (2) 0.030 (2) 0.018 (2) 0.019 (2)

Geometric parameters (Å, º)

Br1—C2 1.884 (4) C5—H5 0.9300

Br2—C6 1.894 (4) C7—C9 1.371 (5)

Br3—C4 1.907 (4) C7—C12 1.382 (5)

O—C1 1.381 (4) C8—C10 1.368 (7)

O—C7 1.394 (4) C8—C9 1.388 (6)

C1—C6 1.382 (5) C8—H8 0.9300

C1—C2 1.383 (5) C9—H9 0.9300

C2—C3 1.383 (5) C10—C11 1.372 (7)

C3—C4 1.382 (5) C10—H10 0.9300

C3—H3 0.9300 C11—C12 1.373 (6)

C4—C5 1.362 (5) C11—H11 0.9300

C5—C6 1.379 (5) C12—H12 0.9300

C1—O—C7 117.3 (3) C9—C7—C12 121.3 (4)

O—C1—C6 121.7 (4) C9—C7—O 123.2 (3)

O—C1—C2 119.7 (3) C12—C7—O 115.5 (4)

C6—C1—C2 118.3 (3) C10—C8—C9 120.6 (5)

C1—C2—C3 120.9 (3) C10—C8—H8 119.7

C1—C2—Br1 120.2 (3) C9—C8—H8 119.7

C3—C2—Br1 118.9 (3) C7—C9—C8 118.7 (4)

C4—C3—C2 118.5 (4) C7—C9—H9 120.7

C4—C3—H3 120.8 C8—C9—H9 120.7

C2—C3—H3 120.8 C8—C10—C11 119.6 (5)

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C5—C4—Br3 119.7 (3) C11—C10—H10 120.2

C3—C4—Br3 118.1 (3) C10—C11—C12 121.0 (4)

C4—C5—C6 118.1 (3) C10—C11—H11 119.5

C4—C5—H5 120.9 C12—C11—H11 119.5

C6—C5—H5 120.9 C11—C12—C7 118.7 (5)

C5—C6—C1 121.9 (4) C11—C12—H12 120.7

C5—C6—Br2 119.0 (3) C7—C12—H12 120.7

C1—C6—Br2 119.1 (3)

C7—O—C1—C6 78.7 (4) O—C1—C6—C5 176.1 (3)

C7—O—C1—C2 −107.1 (4) C2—C1—C6—C5 1.8 (6)

O—C1—C2—C3 −175.5 (4) O—C1—C6—Br2 −5.8 (5)

C6—C1—C2—C3 −1.1 (6) C2—C1—C6—Br2 179.9 (3)

O—C1—C2—Br1 6.1 (5) C1—O—C7—C9 26.2 (5)

C6—C1—C2—Br1 −179.5 (3) C1—O—C7—C12 −155.5 (3)

C1—C2—C3—C4 0.1 (6) C12—C7—C9—C8 1.2 (6)

Br1—C2—C3—C4 178.5 (3) O—C7—C9—C8 179.4 (3)

C2—C3—C4—C5 0.4 (6) C10—C8—C9—C7 0.2 (6)

C2—C3—C4—Br3 −178.8 (3) C9—C8—C10—C11 −1.3 (7)

C3—C4—C5—C6 0.2 (6) C8—C10—C11—C12 0.9 (7)

Br3—C4—C5—C6 179.4 (3) C10—C11—C12—C7 0.4 (7)

C4—C5—C6—C1 −1.3 (6) C9—C7—C12—C11 −1.5 (6)