organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

exo-10,11-Di­bromo­tri­cyclo­[6.3.1.02,7]dodeca-2,4,6,9-tetra­ene

aDepartment of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada T1K 3M4
*Correspondence e-mail: boere@uleth.ca

(Received 27 September 2011; accepted 10 October 2011; online 22 October 2011)

The title compound, C12H10Br2, is a bridged ring system based on a homobenzonorbornadiene framework. The exo configuration of one of the Br atoms was previously assigned via NMR correlations and has now been confirmed by the geometry of the solid-state structure. The compound features a Br—C—C—Br torsion angle of 66.68 (12)°, whereby the C atoms in the calculation are respectively sp3- and sp2-hybridized.

Related literature

For the structure of a closely related tribromide compound, see: Hökelek et al. (1991[Hökelek, T., Çakmak, O. & Balcı, M. (1991). Acta Cryst. C47, 1672-1675.]). For other similar solid-state structures based on a homobenzonorbornadiene framework, see: Daştan et al. (1994[Daştan, A., Balcı, M., Hökelek, T., Ülkü, D. & Büyükgüngör, O. (1994). Tetrahedron, 50, 10555-10578.]); Balci et al. (1996[Balci, M., Krawiec, M., Taskeşenligil, Y. & Watson, W. H. (1996). J. Chem. Crystallogr. 26, 413-418.]); Mangion et al. (2001[Mangion, D., Frizzle, M., Arnold, D. R. & Cameron, T. S. (2001). Synthesis, pp. 1215-1222.]). For synthesis of the title compound, see: Kitahonoki et al. (1969[Kitahonoki, K., Takano, Y., Matsuura, A. & Kotera, K. (1969). Tetrahedron, 25, 335-353.]). For derivatization, see: Çakmak & Balci (1989[Çakmak, O. & Balcı, M. (1989). J. Org. Chem. 54, 181-187.]); Bender et al. (2003[Bender, C. O., Dolman, D., Foesier, J. C., Lawson, S. L. & Preuss, K. E. (2003). Can. J. Chem. 81, 37-44.]).

[Scheme 1]

Experimental

Crystal data
  • C12H10Br2

  • Mr = 314.02

  • Triclinic, [P \overline 1]

  • a = 6.8554 (5) Å

  • b = 8.0926 (6) Å

  • c = 10.1024 (7) Å

  • α = 78.936 (1)°

  • β = 78.867 (1)°

  • γ = 83.665 (1)°

  • V = 538.13 (7) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 7.49 mm−1

  • T = 173 K

  • 0.37 × 0.36 × 0.09 mm

Data collection
  • Bruker APEXII CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2008[Bruker (2008). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison Wisconsin, USA.]) Tmin = 0.497, Tmax = 0.746

  • 6108 measured reflections

  • 2354 independent reflections

  • 2240 reflections with I > 2σ(I)

  • Rint = 0.013

Refinement
  • R[F2 > 2σ(F2)] = 0.016

  • wR(F2) = 0.040

  • S = 1.03

  • 2354 reflections

  • 128 parameters

  • H-atom parameters constrained

  • Δρmax = 0.58 e Å−3

  • Δρmin = −0.45 e Å−3

Data collection: APEX2 (Bruker, 2008[Bruker (2008). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison Wisconsin, USA.]); cell refinement: SAINT-Plus (Bruker, 2008[Bruker (2008). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison Wisconsin, USA.]); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: X-SEED (Barbour, 2001[Barbour, L. J. (2001). J. Supramol. Chem. 1, 189-191.]); software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Comment top

In the title molecule (1) ( Fig. 1), an exo-configuration of Br2, which was originally assigned from NMR correlations (Kitahonoki et al., 1969), has now been confirmed by the X-ray data. As such, the stereochemistry of the two enantiomers that assemble in each unit cell can be unambiguously assigned as RRR and SSS (Fig. 2).

A dihedral angle of 66.7 (1)° was calculated for the Br1—C10—C11—Br2 torsion between the exo-configured C11—Br2 and the sp2 hybridized C10—Br1. Additionally, the compound contains a six-membered ring (C8—C9—C10—C11—C1—C12) that exhibits an interesting envelope-type conformation. This conformation matches that observed in other structures based on a homobenzonorbornadiene framework (Balci et al., 1996). The structure reported by Hokelek et al. (1991) differs from 1 only by the presence of a third bromine atom attached to C12 and directed towards the cyclohexene ring (i.e. replacing H12B). However, the precision in C-C bond distances in 1 is on average five times better resulting in a considerably more reliable geometry than that reported for the tribromide.

Compound 1 has proven to be a convenient starting material for the preparation of a variety of substituted benzobarrelenes (Cakmak & Balci, 1989). For example, 1 can be readily converted to 2-bromo-3-deuteriobenzobarrelene (2) over several synthetic steps (Bender et al., 2003) as outlined in Figure 3.

Related literature top

For the structure of a closely related tribromide compound, see: Hokelek et al. (1991). For other similar solid-state structures based on a homobenzonorbornadiene framework, see: Dastan et al. (1994); Balci et al. (1996); Mangion et al. (2001). For synthesis of the title compound, see: Kitahonoki et al. (1969). For derivatization, see: Cakmak & Balci (1989); Bender et al. (2003).

Experimental top

The dibromide (1) was prepared in a one-step process (Kitahonoki et al., 1969) from the addition of dibromocarbene to benzonorbornadiene (3, Figure 3). The desired compound (1, m.p. 355-356 K) was obtained in 27% yield from the reaction mixture by distillation under reduced pressure and recrystallization from acetone-pentane.

Refinement top

Although hydrogen atoms were visible on the Fourier map, they were included at geometrically idealized positions with isotropic displacement parameters and refined in riding mode on their parent atoms with distance constraints: C—H = 1.00, 0.99 and 0.95 Å for methine, methylene and aromatic-type H-atoms, respectively, and Uiso(H) = 1.2Ueq(C). The highest residual peak had a fraction of the electron density of a single H atom and was located 0.77 Å from Br1.

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT-Plus (Bruker, 2008); data reduction: SAINT-Plus (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. A view of 1 plotted with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as spheres of arbitrary radius.
[Figure 2] Fig. 2. The centrosymmetric pair of enantiomers (SSS and RRR) depicted in a packing diagram.
[Figure 3] Fig. 3. Synthesis of exo-3,4-dibromo-6,7-benzobicyclo[3.2.1]octa-2,6-diene (1) and its conversion to 2-bromo-3-deuteriobenzobarrelene (2).
10,11-dibromotricyclo[6.3.1.02,7]dodeca-2,4,6,9-tetraene top
Crystal data top
C12H10Br2Z = 2
Mr = 314.02F(000) = 304
Triclinic, P1Dx = 1.938 Mg m3
Hall symbol: -P 1Melting point = 355–356 K
a = 6.8554 (5) ÅMo Kα radiation, λ = 0.71073 Å
b = 8.0926 (6) ÅCell parameters from 4757 reflections
c = 10.1024 (7) Åθ = 2.6–27.6°
α = 78.936 (1)°µ = 7.49 mm1
β = 78.867 (1)°T = 173 K
γ = 83.665 (1)°Plate, colourless
V = 538.13 (7) Å30.37 × 0.36 × 0.09 mm
Data collection top
Bruker APEXII CCD area-detector
diffractometer
2354 independent reflections
Radiation source: fine-focus sealed tube2240 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.013
Detector resolution: 66.06 pixels mm-1θmax = 27.1°, θmin = 2.1°
ϕ and ω scansh = 88
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
k = 1010
Tmin = 0.497, Tmax = 0.746l = 1212
6108 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.016H-atom parameters constrained
wR(F2) = 0.040 w = 1/[σ2(Fo2) + (0.0181P)2 + 0.3469P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max = 0.001
2354 reflectionsΔρmax = 0.58 e Å3
128 parametersΔρmin = 0.45 e Å3
0 restraintsExtinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: heavy-atom methodExtinction coefficient: 0.0205 (9)
Crystal data top
C12H10Br2γ = 83.665 (1)°
Mr = 314.02V = 538.13 (7) Å3
Triclinic, P1Z = 2
a = 6.8554 (5) ÅMo Kα radiation
b = 8.0926 (6) ŵ = 7.49 mm1
c = 10.1024 (7) ÅT = 173 K
α = 78.936 (1)°0.37 × 0.36 × 0.09 mm
β = 78.867 (1)°
Data collection top
Bruker APEXII CCD area-detector
diffractometer
2354 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
2240 reflections with I > 2σ(I)
Tmin = 0.497, Tmax = 0.746Rint = 0.013
6108 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0160 restraints
wR(F2) = 0.040H-atom parameters constrained
S = 1.03Δρmax = 0.58 e Å3
2354 reflectionsΔρmin = 0.45 e Å3
128 parameters
Special details top

Experimental. A crystal coated in Paratone (TM) oil was mounted on the end of a thin glass fiber and cooled in the gas stream of the diffractometer Kryoflex low temperature device.

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
Br10.21938 (3)0.19786 (2)0.215988 (17)0.02899 (7)
Br20.61510 (3)0.37752 (2)0.314452 (18)0.03298 (7)
C100.2653 (2)0.43063 (19)0.19221 (16)0.0202 (3)
C90.2194 (2)0.5361 (2)0.08314 (16)0.0210 (3)
H90.17280.49440.01410.025*
C110.3411 (2)0.48460 (19)0.30557 (16)0.0206 (3)
H110.25160.44640.39440.025*
C70.0743 (2)0.79247 (18)0.17148 (15)0.0193 (3)
C10.3474 (2)0.67785 (19)0.28318 (16)0.0198 (3)
H10.42750.71350.34430.024*
C20.1358 (2)0.76059 (18)0.29894 (15)0.0188 (3)
C120.4241 (2)0.7434 (2)0.13037 (16)0.0224 (3)
H12A0.45610.86270.11420.027*
H12B0.54280.67350.09380.027*
C80.2415 (2)0.72350 (19)0.06857 (16)0.0209 (3)
H80.24630.78600.02740.025*
C50.2360 (2)0.9194 (2)0.27206 (18)0.0246 (3)
H50.36340.97560.26360.029*
C30.0114 (2)0.8056 (2)0.41336 (16)0.0224 (3)
H30.05200.78170.50020.027*
C40.1757 (2)0.8871 (2)0.39833 (17)0.0254 (3)
H40.26240.92080.47550.030*
C60.1118 (2)0.8703 (2)0.15684 (17)0.0225 (3)
H60.15440.89010.07070.027*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.04010 (11)0.01927 (9)0.02778 (10)0.00622 (7)0.00221 (7)0.00608 (6)
Br20.03114 (11)0.03503 (11)0.03414 (11)0.01206 (7)0.01449 (7)0.00890 (7)
C100.0213 (7)0.0171 (7)0.0224 (7)0.0028 (6)0.0008 (6)0.0064 (6)
C90.0197 (7)0.0237 (8)0.0207 (7)0.0012 (6)0.0027 (6)0.0078 (6)
C110.0213 (7)0.0206 (7)0.0197 (7)0.0022 (6)0.0047 (6)0.0040 (6)
C70.0222 (7)0.0155 (7)0.0200 (7)0.0026 (6)0.0032 (6)0.0028 (5)
C10.0188 (7)0.0206 (7)0.0214 (7)0.0012 (6)0.0047 (6)0.0057 (6)
C20.0197 (7)0.0156 (7)0.0216 (7)0.0022 (5)0.0037 (6)0.0036 (5)
C120.0204 (7)0.0217 (8)0.0241 (8)0.0029 (6)0.0003 (6)0.0041 (6)
C80.0233 (8)0.0206 (7)0.0176 (7)0.0005 (6)0.0026 (6)0.0021 (6)
C50.0189 (7)0.0211 (8)0.0334 (9)0.0001 (6)0.0045 (6)0.0048 (6)
C30.0254 (8)0.0218 (8)0.0206 (7)0.0027 (6)0.0038 (6)0.0052 (6)
C40.0239 (8)0.0240 (8)0.0270 (8)0.0019 (6)0.0022 (6)0.0079 (6)
C60.0234 (8)0.0199 (7)0.0250 (8)0.0019 (6)0.0075 (6)0.0026 (6)
Geometric parameters (Å, º) top
Br1—C101.9061 (15)C1—H11.0000
Br2—C111.9908 (15)C2—C31.382 (2)
C10—C91.325 (2)C12—C81.539 (2)
C10—C111.498 (2)C12—H12A0.9900
C9—C81.517 (2)C12—H12B0.9900
C9—H90.9500C8—H81.0000
C11—C11.541 (2)C5—C41.385 (2)
C11—H111.0000C5—C61.399 (2)
C7—C61.380 (2)C5—H50.9500
C7—C21.400 (2)C3—C41.397 (2)
C7—C81.526 (2)C3—H30.9500
C1—C21.521 (2)C4—H40.9500
C1—C121.541 (2)C6—H60.9500
C9—C10—C11123.77 (14)C8—C12—C1100.48 (12)
C9—C10—Br1119.62 (12)C8—C12—H12A111.7
C11—C10—Br1116.49 (11)C1—C12—H12A111.7
C10—C9—C8119.94 (14)C8—C12—H12B111.7
C10—C9—H9120.0C1—C12—H12B111.7
C8—C9—H9120.0H12A—C12—H12B109.4
C10—C11—C1111.60 (13)C9—C8—C7107.28 (12)
C10—C11—Br2109.24 (10)C9—C8—C12107.79 (13)
C1—C11—Br2108.86 (10)C7—C8—C12100.49 (12)
C10—C11—H11109.0C9—C8—H8113.4
C1—C11—H11109.0C7—C8—H8113.4
Br2—C11—H11109.0C12—C8—H8113.4
C6—C7—C2120.87 (14)C4—C5—C6120.84 (15)
C6—C7—C8131.24 (14)C4—C5—H5119.6
C2—C7—C8107.87 (13)C6—C5—H5119.6
C2—C1—C11109.58 (12)C2—C3—C4118.46 (15)
C2—C1—C12100.65 (12)C2—C3—H3120.8
C11—C1—C12108.97 (12)C4—C3—H3120.8
C2—C1—H1112.3C5—C4—C3120.70 (15)
C11—C1—H1112.3C5—C4—H4119.7
C12—C1—H1112.3C3—C4—H4119.7
C3—C2—C7120.78 (14)C7—C6—C5118.33 (15)
C3—C2—C1130.10 (14)C7—C6—H6120.8
C7—C2—C1109.11 (13)C5—C6—H6120.8
C11—C10—C9—C80.4 (2)C2—C1—C12—C842.36 (14)
Br1—C10—C9—C8175.59 (11)C11—C1—C12—C872.80 (14)
C9—C10—C11—C13.2 (2)C10—C9—C8—C772.51 (18)
Br1—C10—C11—C1172.90 (10)C10—C9—C8—C1234.95 (19)
C9—C10—C11—Br2117.19 (15)C6—C7—C8—C995.45 (19)
Br1—C10—C11—Br266.68 (12)C2—C7—C8—C982.96 (15)
C10—C11—C1—C268.38 (16)C6—C7—C8—C12152.03 (16)
Br2—C11—C1—C2170.97 (10)C2—C7—C8—C1229.56 (15)
C10—C11—C1—C1240.88 (17)C1—C12—C8—C968.19 (14)
Br2—C11—C1—C1279.77 (13)C1—C12—C8—C743.94 (14)
C6—C7—C2—C30.3 (2)C7—C2—C3—C41.4 (2)
C8—C7—C2—C3178.29 (14)C1—C2—C3—C4177.45 (15)
C6—C7—C2—C1178.77 (14)C6—C5—C4—C30.4 (2)
C8—C7—C2—C12.62 (16)C2—C3—C4—C51.1 (2)
C11—C1—C2—C391.68 (19)C2—C7—C6—C51.1 (2)
C12—C1—C2—C3153.62 (16)C8—C7—C6—C5179.37 (15)
C11—C1—C2—C789.35 (15)C4—C5—C6—C71.5 (2)
C12—C1—C2—C725.36 (15)

Experimental details

Crystal data
Chemical formulaC12H10Br2
Mr314.02
Crystal system, space groupTriclinic, P1
Temperature (K)173
a, b, c (Å)6.8554 (5), 8.0926 (6), 10.1024 (7)
α, β, γ (°)78.936 (1), 78.867 (1), 83.665 (1)
V3)538.13 (7)
Z2
Radiation typeMo Kα
µ (mm1)7.49
Crystal size (mm)0.37 × 0.36 × 0.09
Data collection
DiffractometerBruker APEXII CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2008)
Tmin, Tmax0.497, 0.746
No. of measured, independent and
observed [I > 2σ(I)] reflections
6108, 2354, 2240
Rint0.013
(sin θ/λ)max1)0.641
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.016, 0.040, 1.03
No. of reflections2354
No. of parameters128
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.58, 0.45

Computer programs: APEX2 (Bruker, 2008), SAINT-Plus (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), X-SEED (Barbour, 2001), publCIF (Westrip, 2010).

 

Acknowledgements

Sherry Lawson and Douglas Dolman are thanked for the sample preparation. This research was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada. The diffractometer at the University of Lethbridge X-ray Diffraction Facility was purchased with the help of NSERC and the University of Lethbridge.

References

First citationBalci, M., Krawiec, M., Taskeşenligil, Y. & Watson, W. H. (1996). J. Chem. Crystallogr. 26, 413–418.  CSD CrossRef CAS Web of Science Google Scholar
First citationBarbour, L. J. (2001). J. Supramol. Chem. 1, 189–191.  CrossRef CAS Google Scholar
First citationBender, C. O., Dolman, D., Foesier, J. C., Lawson, S. L. & Preuss, K. E. (2003). Can. J. Chem. 81, 37–44.  Web of Science CrossRef CAS Google Scholar
First citationBruker (2008). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison Wisconsin, USA.  Google Scholar
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First citationDaştan, A., Balcı, M., Hökelek, T., Ülkü, D. & Büyükgüngör, O. (1994). Tetrahedron, 50, 10555–10578.  CSD CrossRef CAS Web of Science Google Scholar
First citationHökelek, T., Çakmak, O. & Balcı, M. (1991). Acta Cryst. C47, 1672–1675.  CSD CrossRef Web of Science IUCr Journals Google Scholar
First citationKitahonoki, K., Takano, Y., Matsuura, A. & Kotera, K. (1969). Tetrahedron, 25, 335–353.  CrossRef CAS Web of Science Google Scholar
First citationMangion, D., Frizzle, M., Arnold, D. R. & Cameron, T. S. (2001). Synthesis, pp. 1215–1222.  CSD CrossRef Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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