organic papers
Acta Cryst.(2004). E60, o1499±o1500 DOI: 10.1107/S160053680401709X Hemamala Karunadasaet al. C20H24Br2
o1499
Acta Crystallographica Section EStructure Reports Online
ISSN 1600-5368
2,2
000-Dibromo-3,3
000,4,4
000,5,5
000,6,6
000-octamethyl-1,1
000-biphenyl
Hemamala Karunadasa,* Christina Leggett and Shaun Wong
College of Chemistry, University of California at Berkeley, Berkeley, CA 94720, USA
Correspondence e-mail: hemamala@berkeley.edu
Key indicators Single-crystal X-ray study T= 174 K
Mean(C±C) = 0.007 AÊ Disorder in main residue Rfactor = 0.038 wRfactor = 0.050
Data-to-parameter ratio = 10.5
For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.
#2004 International Union of Crystallography Printed in Great Britain ± all rights reserved
The title compound, C29H24Br2, has crystallographic twofold rotation symmetry. The Br atom in the 2 position is disordered with the methyl group in the 6 position. The biphenyl bridge bond distance and the torsion angle between the rings are in good agreement with similar previously reported structures.
Comment
The title compound, (I), crystallizes in the space groupPbcn, with the molecule on a crystallographic twofold axis, which bisects the angle between the two rings. One half of the molecule consists of a benzene ring, to which are bonded a Br atom and four methyl groups. The Br atom is bonded in the 2 position and is disordered between the 2 and 6 positions. The methyl group in the 6 position is concomitantly disordered.
The major-component C2ÐBr1 distance is 1.871 (4) AÊ and the minor-component C6ÐBr2 distance is 1.809 (5) AÊ. The major-component C2ÐBr1 distance is comparable to the CÐ Br distances in 2,20-dibromobiphenyl (1.895 and 1.905 AÊ;
MacNeil & Decken, 1999).
The CÐC distance of the biphenyl bridge is 1.502 (9) AÊ, similar to that of 2,20-dibromobiphenyl (1.499 AÊ),
deca-chlorobiphenyl (1.522 AÊ; Pedersen, 1975) and decakis(di-chloromethyl)biphenyl (1.534 AÊ; Bialiet al., 1988).
The interplanar angle between the phenyl rings in the molecule is 85.2 (8). This compares well with the
corres-ponding angles in 2,20-dibromobiphenyl (86.0),
decachloro-biphenyl (86.7) and decakis(dichloromethyl)biphenyl (84.4).
Experimental
The title compound was synthesized according to a previously reported method (Shibataet al., 2003).
Crystal data
C20H24Br2
Mr= 424.22
Orthorhombic,Pbcn a= 13.530 (4) AÊ
b= 10.987 (4) AÊ
c= 11.916 (3) AÊ
V= 1771.4 (9) AÊ3
Z= 4
Dx= 1.591 Mg mÿ3
Mo Kradiation Cell parameters from 2260
re¯ections
= 2.4±24.0
= 4.59 mmÿ1
T= 174.2 K Block, colorless 0.290.210.13 mm
Data collection
Bruker SMART 1000 diffractometer
!scans
Absorption correction: multi-scan (Blessing, 1995)
Tmin= 0.280,Tmax= 0.554
7776 measured re¯ections
1483 independent re¯ections 1061 re¯ections withI> 3(I)
Rint= 0.046
max= 24.7
h=ÿ13!15
k=ÿ12!12
l=ÿ13!13
Re®nement
Re®nement onF R= 0.038
wR= 0.050
S= 1.85 1061 re¯ections 101 parameters
H-atom parameters constrained
w= 1/[2(F
o) + 0.00022|Fo|2]
(/)max< 0.001
max= 0.28 e AÊÿ3
min=ÿ0.35 e AÊÿ3
Table 1
Selected geometric parameters (AÊ,).
Br1ÐC2 1.871 (4)
Br2ÐC6 1.809 (5) C1ÐC1
i 1.502 (9)
C2ÐC1ÐC1iÐC2i ÿ83.7 (8) C2ÐC1ÐC1iÐC6i 95.6 (3) Symmetry code: (i) 1ÿx;y;3
2ÿz.
Table 2
Contact distances (AÊ).
Br1 Br2ii 3.557 (2)
Br2 C11iii 3.502 (2) Br2 Br2
iv 3.532 (4)
Symmetry codes: (ii)x;ÿy;zÿ1
2; (iii)x;ÿy;12z; (iv) 1ÿx;ÿy;2ÿz.
Atoms C10 and C11 were inserted along the CÐBr bonds at a ®xed distance of 1.54 AÊ from the ring C atoms. The displacement parameters of these atoms were ®xed at 0.0456 AÊ2 because their positions are not well de®ned and the CÐBr distance is too short to allow for proper resolution of the disordered atoms. The Br1 atom occupancy was allowed to re®ne and then ®xed at 0.73. The occu-pancies of atoms Br2, C10 and C11 were tied appropriately to that of Br1.
Data collection:SMART(Bruker, 2003); cell re®nement:SAINT
(Bruker, 2003); data reduction: SAINT; program(s) used to solve structure:SIR97 (Altomareet al., 1999); program(s) used to re®ne
structure: TEXSAN (Molecular Structure Corporation & Rigaku, 1998); molecular graphics: TEXSAN; software used to prepare material for publication:TEXSAN.
The authors acknowledge Dr Fred Hollander, Dr Allen Oliver and Professor Kenneth N. Raymond for their invalu-able assistance. We also thank Karl Tupper for providing the sample.
References
Altomare, A., Burla, M. C., Camalli, M., Cascarano, G., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999).J. Appl. Cryst.32, 115±119.
Biali, S. E., Kahr, B., Okamoto, Y., Aburatani, R. & Mislow, K. (1988).J. Am. Chem. Soc.110, 1917±1922.
Blessing, R. H. (1995).Acta Cryst.A51, 33±38.
Bruker (2003).SMART(Version 5.631) andSAINT(Version 6.40). Bruker AXS Inc., Madison, Wisconsin, USA.
MacNeil, D. D. & Decken, A. (1999).Acta Cryst.C55, 628±630.
Molecular Structure Corporation & Rigaku (1998).TEXSAN.Version 1.10. MSC, 3200 Research Forest Drive, The Woodlands, TX 77381, USA, and Rigaku Corporation, 3-9-12 Akishima, Tokyo, Japan.
Pedersen, B. F. (1975).Acta Cryst.B31, 2931±2933.
Shibata, T., Tsuruta, H., Danjo, H. & Imamoto, T. (2003).J. Mol. Cat. A,196, 117±124.
Figure 1
supporting information
sup-1
Acta Cryst. (2004). E60, o1499–o1500
supporting information
Acta Cryst. (2004). E60, o1499–o1500 [https://doi.org/10.1107/S160053680401709X]
2,2
′
-Dibromo-3,3
′
,4,4
′
,5,5
′
,6,6
′
-octamethyl-1,1
′
-biphenyl
Hemamala Karunadasa, Christina Leggett and Shaun Wong
(I)
Crystal data C20H24Br2 Mr = 424.22
Orthorhombic, Pbcn Hall symbol: -P 2n 2ab a = 13.530 (4) Å b = 10.987 (4) Å c = 11.916 (3) Å V = 1771.4 (9) Å3 Z = 4
F(000) = 856.00 Dx = 1.591 Mg m−3
Mo Kα radiation, λ = 0.7107 Å Cell parameters from 2260 reflections θ = 2.4–24.0°
µ = 4.59 mm−1 T = 174 K Block, colorless 0.29 × 0.21 × 0.13 mm
Data collection Bruker SMART 1000
diffractometer ω scans
Absorption correction: multi-scan (Blessing, 1995)
Tmin = 0.280, Tmax = 0.554
7776 measured reflections
1483 independent reflections 1061 reflections with I > 3σ(I) Rint = 0.046
θmax = 24.7° h = −13→15 k = −12→12 l = −13→13
Refinement Refinement on F R[F2 > 2σ(F2)] = 0.038 wR(F2) = 0.050 S = 1.85 1061 reflections 101 parameters
H-atom parameters constrained w = 1/[σ2(F
o) + 0.00022|Fo|2]
(Δ/σ)max = 0.0004
Δρmax = 0.28 e Å−3
Δρmin = −0.35 e Å−3
Special details
Refinement. Refinement using reflections with F2 > 3.0 σ(F2). The weighted R-factor (wR), goodness of fit (S) and R
-factor (gt) are based on F, with F set to zero for negative F. The threshold expression of F2 > 3.0 σ(F2) is used only for
calculating R-factor (gt).
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)
x y z Uiso*/Ueq Occ. (<1)
Br1 0.51423 (5) 0.30856 (6) 0.58452 (5) 0.0328 (2) 0.73
Br2 0.5631 (2) −0.0719 (2) 0.8885 (2) 0.0435 (7) 0.27
C1 0.5548 (3) 0.1223 (4) 0.7401 (3) 0.023 (1)
C3 0.6999 (3) 0.2099 (4) 0.6462 (4) 0.028 (1)
C4 0.7598 (3) 0.1318 (4) 0.7077 (4) 0.031 (1)
C5 0.7193 (4) 0.0475 (4) 0.7826 (4) 0.031 (2)
C6 0.6175 (3) 0.0418 (4) 0.7977 (4) 0.027 (1)
C7 0.7430 (4) 0.3007 (4) 0.5645 (4) 0.040 (2)
C8 0.8722 (4) 0.1364 (5) 0.6924 (5) 0.047 (2)
C9 0.7856 (4) −0.0392 (5) 0.8466 (5) 0.050 (2)
C10 0.5712 −0.0551 0.8752 0.0456* 0.73
C11 0.5287 0.2909 0.5984 0.0456* 0.27
H1 0.7893 0.3511 0.6023 0.0477*
H2 0.7752 0.2585 0.5053 0.0477*
H3 0.6914 0.3496 0.5344 0.0477*
H4 0.8893 0.2055 0.6486 0.0567*
H5 0.8938 0.0646 0.6553 0.0567*
H6 0.9031 0.1420 0.7637 0.0567*
H7 0.8321 0.0061 0.8894 0.0600*
H8 0.7467 −0.0879 0.8953 0.0600*
H9 0.8198 −0.0900 0.7951 0.0600*
H10 0.5019 −0.0424 0.8796 0.0547* 0.73
H11 0.5840 −0.1338 0.8457 0.0547* 0.73
H12 0.5993 −0.0486 0.9480 0.0547* 0.73
H13 0.5533 0.3717 0.6038 0.0547* 0.27
H14 0.5268 0.2670 0.5218 0.0547* 0.27
H15 0.4640 0.2875 0.6290 0.0547* 0.27
Atomic displacement parameters (Å2)
U11 U22 U33 U12 U13 U23
Br1 0.0289 (4) 0.0322 (4) 0.0374 (4) 0.0051 (3) 0.0004 (3) 0.0080 (3)
Br2 0.053 (2) 0.041 (1) 0.037 (1) 0.0124 (10) 0.0117 (9) 0.0174 (9)
C1 0.024 (2) 0.020 (3) 0.027 (3) −0.001 (2) 0.004 (2) −0.005 (2)
C2 0.023 (3) 0.021 (3) 0.028 (3) 0.001 (2) 0.001 (2) −0.001 (2)
C3 0.027 (3) 0.029 (3) 0.030 (3) −0.001 (2) 0.006 (2) −0.008 (2)
C4 0.018 (3) 0.035 (3) 0.039 (3) 0.002 (2) 0.002 (2) −0.014 (2)
C5 0.031 (3) 0.033 (3) 0.031 (3) 0.009 (2) −0.003 (2) −0.009 (2)
C6 0.031 (3) 0.026 (3) 0.025 (3) 0.005 (2) 0.002 (2) −0.002 (2)
C7 0.034 (3) 0.038 (3) 0.047 (3) −0.001 (2) 0.013 (2) 0.005 (3)
C8 0.027 (3) 0.051 (4) 0.064 (4) 0.003 (3) 0.003 (3) −0.005 (3)
C9 0.044 (3) 0.049 (3) 0.057 (4) 0.023 (3) −0.003 (3) 0.001 (3)
Geometric parameters (Å, º)
Br1—C2 1.871 (4) C7—H2 0.950
Br2—C6 1.809 (5) C7—H3 0.950
C1—C1i 1.502 (9) C8—H4 0.950
C1—C2 1.395 (6) C8—H5 0.950
C1—C6 1.405 (6) C8—H6 0.950
supporting information
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Acta Cryst. (2004). E60, o1499–o1500
C2—C11 1.549 (4) C9—H8 0.950
C3—C4 1.389 (6) C9—H9 0.950
C3—C7 1.511 (6) C10—H10 0.950
C4—C5 1.399 (7) C10—H11 0.950
C4—C8 1.532 (6) C10—H12 0.950
C5—C6 1.390 (6) C11—H13 0.950
C5—C9 1.514 (6) C11—H14 0.950
C6—C10 1.542 (4) C11—H15 0.950
C7—H1 0.950
Br1···Br2ii 3.557 (2) Br2···Br2iv 3.532 (4)
Br2···C11iii 3.502 (2)
C1—C1i—C2i 120.7 (4) H1—C7—H3 109.5
C1—C1i—C6i 121.3 (4) H2—C7—H3 109.5
C2—C1—C6 118.0 (4) C4—C8—H4 109.5
Br1—C2—C1 118.3 (3) C4—C8—H5 109.5
Br1—C2—C3 119.1 (3) C4—C8—H6 109.5
C1—C2—C3 122.6 (4) H4—C8—H5 109.5
C1—C2—C11 118.5 (3) H4—C8—H6 109.5
C3—C2—C11 118.9 (3) H5—C8—H6 109.5
C2—C3—C4 117.7 (4) C5—C9—H7 109.5
C2—C3—C7 120.8 (4) C5—C9—H8 109.5
C4—C3—C7 121.5 (4) C5—C9—H9 109.5
C3—C4—C5 121.1 (4) H7—C9—H8 109.5
C3—C4—C8 119.7 (5) H7—C9—H9 109.5
C5—C4—C8 119.1 (4) H8—C9—H9 109.5
C4—C5—C6 120.0 (4) C6—C10—H10 109.5
C4—C5—C9 120.4 (4) C6—C10—H11 109.5
C6—C5—C9 119.6 (4) C6—C10—H12 109.5
Br2—C6—C1 118.8 (3) H10—C10—H11 109.5
Br2—C6—C5 120.7 (4) H10—C10—H12 109.5
C1—C6—C5 120.5 (4) H11—C10—H12 109.5
C1—C6—C10 118.8 (4) C2—C11—H13 109.5
C5—C6—C10 120.7 (4) C2—C11—H14 109.5
C3—C7—H1 109.5 C2—C11—H15 109.5
C3—C7—H2 109.5 H13—C11—H14 109.5
C3—C7—H3 109.5 H13—C11—H15 109.5
H1—C7—H2 109.5 H14—C11—H15 109.5
Br1—C2—C1—C1i −2.2 (6) C2—C1—C6—C5 2.7 (6)
Br1—C2—C1—C6 178.5 (3) C2—C1—C6—C10 −175.6 (3)
Br1—C2—C3—C4 179.3 (3) C2—C3—C4—C5 1.8 (7)
Br1—C2—C3—C7 0.7 (6) C2—C3—C4—C8 −179.0 (4)
Br2—C6—C1—C1i 5.2 (6) C3—C2—C1—C6 −1.7 (6)
Br2—C6—C1—C2 −175.5 (3) C3—C4—C5—C6 −0.8 (7)
Br2—C6—C5—C4 176.7 (4) C3—C4—C5—C9 178.4 (4)
C1—C1i—C2i—C3i 177.6 (4) C4—C5—C6—C10 176.7 (4)
C1—C1i—C2i—C11i −2.1 (6) C5—C4—C3—C7 −179.6 (4)
C1—C1i—C6i—C5i −176.6 (4) C6—C1—C1i—C6i −85.1 (8)
C1—C1i—C6i—C10i 5.1 (6) C6—C1—C2—C11 178.6 (3)
C1—C2—C3—C4 −0.5 (7) C6—C5—C4—C8 180.0 (4)
C1—C2—C3—C7 −179.2 (4) C7—C3—C2—C11 0.5 (6)
C1—C6—C5—C4 −1.5 (7) C7—C3—C4—C8 −0.4 (7)
C1—C6—C5—C9 179.3 (4) C8—C4—C5—C9 −0.8 (7)
C2—C1—C1i—C2i −83.7 (8) C9—C5—C6—C10 −2.5 (6)
C2—C1—C1i—C6i 95.6 (3)