Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S010827011300231X/gz3227sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S010827011300231X/gz3227Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S010827011300231X/gz3227IIsup3.hkl |
CCDC references: 934559; 934560
Tetrabromide (I) was readily prepared by the addition of bromine to (III) at 253 K, accompanied by a rearrangement of the hydrocarbon cage, as shown in Scheme 1 (Kitahonoki et al., 1969; Johnson et al., 2011). Recrystallization of the reaction mixture from chloroform–hexane [Solvent ratio?] gave colourless rod-shaped [Block in CIF tables - please clarify] crystals of (I) (yield 54%, m.p. 418–419 K). Dibromide (II) was prepared by the double dehydrobromination of (I), according to the method of Çakmak & Balcı (1989) (yield > 80%, m.p. 344–345 K). [Recrystallization details?]
C-bound H atoms were treated as riding, with C—H = 0.99 Å and Uiso(H) = 1.2Ueq(C) for methylene, C—H = 1.00 Å and Uiso(H) = 1.2Ueq(C) for methine, and C—H = 0.95 Å and Uiso(H) = 1.2Ueq(C) for vinyl and aromatic H atoms. No data were rejected for (I), but three intense reflections and one inconsistent equivalent in the data set of (II) were omitted from the refinement. The largest peak and hole in the final difference maps approach the equivalent electron density of an H atom but are located less than 1 Å from Br atoms.
For both compounds, 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: Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).
C12H10Br4 | Z = 2 |
Mr = 473.84 | F(000) = 444 |
Triclinic, P1 | Dx = 2.412 Mg m−3 |
Hall symbol: -P 1 | Melting point: 418 K |
a = 6.9532 (4) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 8.4323 (5) Å | Cell parameters from 6183 reflections |
c = 11.9669 (7) Å | θ = 2.6–28.3° |
α = 94.706 (1)° | µ = 12.31 mm−1 |
β = 91.257 (1)° | T = 173 K |
γ = 110.892 (1)° | Block, colourless |
V = 652.31 (7) Å3 | 0.45 × 0.27 × 0.27 mm |
Bruker APEXII CCD area-detector diffractometer | 3074 independent reflections |
Radiation source: fine-focus sealed tube, Bruker D8 | 2835 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.024 |
Detector resolution: 66.06 pixels mm-1 | θmax = 28.3°, θmin = 1.7° |
ϕ and ω scans | h = −9→9 |
Absorption correction: numerical (SADABS; Bruker, 2008) | k = −10→11 |
Tmin = 0.052, Tmax = 0.144 | l = −15→15 |
7682 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.022 | H-atom parameters constrained |
wR(F2) = 0.055 | w = 1/[σ2(Fo2) + (0.0202P)2 + 0.8639P] where P = (Fo2 + 2Fc2)/3 |
S = 1.05 | (Δ/σ)max = 0.001 |
3074 reflections | Δρmax = 0.78 e Å−3 |
146 parameters | Δρmin = −0.78 e Å−3 |
0 restraints | Extinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0097 (6) |
C12H10Br4 | γ = 110.892 (1)° |
Mr = 473.84 | V = 652.31 (7) Å3 |
Triclinic, P1 | Z = 2 |
a = 6.9532 (4) Å | Mo Kα radiation |
b = 8.4323 (5) Å | µ = 12.31 mm−1 |
c = 11.9669 (7) Å | T = 173 K |
α = 94.706 (1)° | 0.45 × 0.27 × 0.27 mm |
β = 91.257 (1)° |
Bruker APEXII CCD area-detector diffractometer | 3074 independent reflections |
Absorption correction: numerical (SADABS; Bruker, 2008) | 2835 reflections with I > 2σ(I) |
Tmin = 0.052, Tmax = 0.144 | Rint = 0.024 |
7682 measured reflections |
R[F2 > 2σ(F2)] = 0.022 | 0 restraints |
wR(F2) = 0.055 | H-atom parameters constrained |
S = 1.05 | Δρmax = 0.78 e Å−3 |
3074 reflections | Δρmin = −0.78 e Å−3 |
146 parameters |
Experimental. A crystal coated in Paratone (TM) oil was mounted on the end of a thin glass capillary and cooled in the gas stream of the diffractometer Kryoflex device. On consideration of the large absorption coefficient, a face-indexed numerical absorption correction was undertaken using SADABS software. |
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 | 0.89779 (5) | 0.17616 (4) | 0.04487 (2) | 0.03611 (9) | |
Br2 | 1.08266 (4) | 0.55118 (3) | 0.18715 (2) | 0.02900 (8) | |
Br3 | 1.03300 (4) | 0.31408 (4) | 0.37875 (2) | 0.02923 (8) | |
Br4 | 0.70724 (4) | 0.72876 (3) | 0.18717 (2) | 0.03075 (9) | |
C1 | 0.7185 (3) | 0.4386 (3) | 0.3143 (2) | 0.0182 (4) | |
H1 | 0.7836 | 0.5321 | 0.3756 | 0.022* | |
C2 | 0.5540 (4) | 0.2863 (3) | 0.3576 (2) | 0.0199 (5) | |
C3 | 0.4997 (4) | 0.2671 (3) | 0.4675 (2) | 0.0249 (5) | |
H3 | 0.5704 | 0.3528 | 0.5260 | 0.030* | |
C4 | 0.3393 (4) | 0.1196 (4) | 0.4913 (2) | 0.0313 (6) | |
H4 | 0.3012 | 0.1047 | 0.5666 | 0.038* | |
C5 | 0.2358 (4) | −0.0045 (4) | 0.4063 (3) | 0.0327 (6) | |
H5 | 0.1265 | −0.1038 | 0.4235 | 0.039* | |
C6 | 0.2899 (4) | 0.0143 (3) | 0.2960 (3) | 0.0300 (6) | |
H6 | 0.2184 | −0.0716 | 0.2378 | 0.036* | |
C7 | 0.4492 (4) | 0.1597 (3) | 0.2715 (2) | 0.0220 (5) | |
C8 | 0.5393 (4) | 0.1937 (3) | 0.1582 (2) | 0.0223 (5) | |
H8 | 0.4660 | 0.0973 | 0.1001 | 0.027* | |
C9 | 0.7635 (4) | 0.2064 (3) | 0.1817 (2) | 0.0214 (5) | |
H9 | 0.7562 | 0.1092 | 0.2261 | 0.026* | |
C10 | 0.8784 (3) | 0.3726 (3) | 0.2598 (2) | 0.0188 (4) | |
C11 | 0.5907 (4) | 0.4919 (3) | 0.2267 (2) | 0.0202 (5) | |
H11 | 0.4572 | 0.4802 | 0.2612 | 0.024* | |
C12 | 0.5356 (4) | 0.3639 (3) | 0.1222 (2) | 0.0248 (5) | |
H12A | 0.6367 | 0.4055 | 0.0645 | 0.030* | |
H12B | 0.3969 | 0.3484 | 0.0902 | 0.030* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.03552 (16) | 0.04056 (17) | 0.03069 (16) | 0.01369 (13) | 0.01088 (11) | −0.00776 (11) |
Br2 | 0.02253 (13) | 0.02120 (13) | 0.04350 (17) | 0.00627 (10) | 0.01178 (11) | 0.00922 (10) |
Br3 | 0.02532 (14) | 0.03823 (16) | 0.02935 (15) | 0.01712 (11) | −0.00090 (10) | 0.00695 (11) |
Br4 | 0.03562 (16) | 0.02153 (13) | 0.03915 (16) | 0.01381 (11) | 0.00586 (11) | 0.00839 (10) |
C1 | 0.0176 (10) | 0.0165 (10) | 0.0201 (11) | 0.0063 (9) | −0.0001 (8) | −0.0004 (8) |
C2 | 0.0174 (11) | 0.0204 (11) | 0.0232 (12) | 0.0081 (9) | 0.0031 (9) | 0.0037 (9) |
C3 | 0.0258 (12) | 0.0301 (13) | 0.0229 (12) | 0.0147 (11) | 0.0020 (10) | 0.0031 (10) |
C4 | 0.0290 (13) | 0.0399 (15) | 0.0321 (14) | 0.0175 (12) | 0.0108 (11) | 0.0179 (12) |
C5 | 0.0255 (13) | 0.0269 (13) | 0.0485 (17) | 0.0094 (11) | 0.0132 (12) | 0.0166 (12) |
C6 | 0.0233 (12) | 0.0203 (12) | 0.0433 (16) | 0.0039 (10) | 0.0042 (11) | 0.0034 (11) |
C7 | 0.0192 (11) | 0.0187 (11) | 0.0276 (13) | 0.0061 (9) | 0.0042 (9) | 0.0020 (9) |
C8 | 0.0206 (11) | 0.0212 (11) | 0.0215 (12) | 0.0041 (9) | 0.0006 (9) | −0.0030 (9) |
C9 | 0.0242 (12) | 0.0189 (11) | 0.0211 (11) | 0.0077 (9) | 0.0054 (9) | 0.0003 (9) |
C10 | 0.0157 (10) | 0.0196 (11) | 0.0210 (11) | 0.0061 (9) | 0.0018 (8) | 0.0032 (9) |
C11 | 0.0176 (11) | 0.0187 (11) | 0.0243 (12) | 0.0062 (9) | 0.0001 (9) | 0.0034 (9) |
C12 | 0.0227 (12) | 0.0280 (13) | 0.0224 (12) | 0.0080 (10) | −0.0030 (9) | 0.0010 (10) |
Br1—C9 | 1.946 (2) | C5—C6 | 1.386 (4) |
Br2—C10 | 1.945 (2) | C5—H5 | 0.9500 |
Br3—C10 | 1.963 (2) | C6—C7 | 1.386 (4) |
Br4—C11 | 1.972 (2) | C6—H6 | 0.9500 |
C1—C2 | 1.521 (3) | C7—C8 | 1.512 (3) |
C1—C10 | 1.544 (3) | C8—C12 | 1.540 (4) |
C1—C11 | 1.553 (3) | C8—C9 | 1.542 (3) |
C1—H1 | 1.0000 | C8—H8 | 1.0000 |
C2—C3 | 1.383 (3) | C9—C10 | 1.558 (3) |
C2—C7 | 1.401 (3) | C9—H9 | 1.0000 |
C3—C4 | 1.398 (4) | C11—C12 | 1.529 (3) |
C3—H3 | 0.9500 | C11—H11 | 1.0000 |
C4—C5 | 1.380 (4) | C12—H12A | 0.9900 |
C4—H4 | 0.9500 | C12—H12B | 0.9900 |
C2—C1—C10 | 106.98 (18) | C7—C8—H8 | 111.1 |
C2—C1—C11 | 101.56 (18) | C12—C8—H8 | 111.1 |
C10—C1—C11 | 112.57 (19) | C9—C8—H8 | 111.1 |
C2—C1—H1 | 111.7 | C8—C9—C10 | 108.73 (19) |
C10—C1—H1 | 111.7 | C8—C9—Br1 | 112.40 (16) |
C11—C1—H1 | 111.7 | C10—C9—Br1 | 115.76 (16) |
C3—C2—C7 | 120.3 (2) | C8—C9—H9 | 106.4 |
C3—C2—C1 | 127.0 (2) | C10—C9—H9 | 106.4 |
C7—C2—C1 | 112.6 (2) | Br1—C9—H9 | 106.4 |
C2—C3—C4 | 119.0 (2) | C1—C10—C9 | 109.21 (19) |
C2—C3—H3 | 120.5 | C1—C10—Br2 | 110.96 (16) |
C4—C3—H3 | 120.5 | C9—C10—Br2 | 114.66 (16) |
C5—C4—C3 | 120.5 (3) | C1—C10—Br3 | 108.67 (16) |
C5—C4—H4 | 119.8 | C9—C10—Br3 | 107.65 (16) |
C3—C4—H4 | 119.8 | Br2—C10—Br3 | 105.43 (11) |
C4—C5—C6 | 120.7 (3) | C12—C11—C1 | 109.83 (19) |
C4—C5—H5 | 119.7 | C12—C11—Br4 | 111.59 (16) |
C6—C5—H5 | 119.7 | C1—C11—Br4 | 116.66 (16) |
C7—C6—C5 | 119.4 (3) | C12—C11—H11 | 106.0 |
C7—C6—H6 | 120.3 | C1—C11—H11 | 106.0 |
C5—C6—H6 | 120.3 | Br4—C11—H11 | 106.0 |
C6—C7—C2 | 120.1 (2) | C11—C12—C8 | 107.5 (2) |
C6—C7—C8 | 126.1 (2) | C11—C12—H12A | 110.2 |
C2—C7—C8 | 113.5 (2) | C8—C12—H12A | 110.2 |
C7—C8—C12 | 111.0 (2) | C11—C12—H12B | 110.2 |
C7—C8—C9 | 102.1 (2) | C8—C12—H12B | 110.2 |
C12—C8—C9 | 110.2 (2) | H12A—C12—H12B | 108.5 |
C10—C1—C2—C3 | 119.7 (3) | C12—C8—C9—Br1 | −80.7 (2) |
C11—C1—C2—C3 | −122.1 (3) | C2—C1—C10—C9 | 46.8 (2) |
C10—C1—C2—C7 | −62.3 (3) | C11—C1—C10—C9 | −64.0 (2) |
C11—C1—C2—C7 | 55.9 (2) | C2—C1—C10—Br2 | 174.12 (15) |
C7—C2—C3—C4 | 0.1 (4) | C11—C1—C10—Br2 | 63.4 (2) |
C1—C2—C3—C4 | 178.0 (2) | C2—C1—C10—Br3 | −70.40 (19) |
C2—C3—C4—C5 | −0.4 (4) | C11—C1—C10—Br3 | 178.88 (15) |
C3—C4—C5—C6 | 0.4 (4) | C8—C9—C10—C1 | 16.4 (3) |
C4—C5—C6—C7 | −0.2 (4) | Br1—C9—C10—C1 | 144.07 (17) |
C5—C6—C7—C2 | −0.1 (4) | C8—C9—C10—Br2 | −108.78 (19) |
C5—C6—C7—C8 | 174.5 (3) | Br1—C9—C10—Br2 | 18.8 (2) |
C3—C2—C7—C6 | 0.1 (4) | C8—C9—C10—Br3 | 134.26 (17) |
C1—C2—C7—C6 | −178.0 (2) | Br1—C9—C10—Br3 | −98.12 (16) |
C3—C2—C7—C8 | −175.1 (2) | C2—C1—C11—C12 | −73.6 (2) |
C1—C2—C7—C8 | 6.7 (3) | C10—C1—C11—C12 | 40.5 (3) |
C6—C7—C8—C12 | 125.7 (3) | C2—C1—C11—Br4 | 158.19 (16) |
C2—C7—C8—C12 | −59.5 (3) | C10—C1—C11—Br4 | −87.7 (2) |
C6—C7—C8—C9 | −116.9 (3) | C1—C11—C12—C8 | 24.5 (3) |
C2—C7—C8—C9 | 58.0 (3) | Br4—C11—C12—C8 | 155.47 (16) |
C7—C8—C9—C10 | −69.2 (2) | C7—C8—C12—C11 | 39.3 (3) |
C12—C8—C9—C10 | 48.8 (3) | C9—C8—C12—C11 | −73.1 (2) |
C7—C8—C9—Br1 | 161.26 (16) |
C12H8Br2 | F(000) = 600 |
Mr = 312.00 | Dx = 1.990 Mg m−3 |
Monoclinic, P21/n | Melting point: 344 K |
Hall symbol: -P 2yn | Mo Kα radiation, λ = 0.71073 Å |
a = 9.520 (3) Å | Cell parameters from 8250 reflections |
b = 6.5032 (18) Å | θ = 2.3–28.7° |
c = 17.124 (5) Å | µ = 7.74 mm−1 |
β = 100.826 (3)° | T = 173 K |
V = 1041.3 (5) Å3 | Block, colourless |
Z = 4 | 0.21 × 0.16 × 0.15 mm |
Bruker APEXII CCD area-detector diffractometer | 2378 independent reflections |
Radiation source: fine-focus sealed tube, Bruker D8 | 2076 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.029 |
Detector resolution: 66.06 pixels mm-1 | θmax = 27.5°, θmin = 2.3° |
ϕ and ω scans | h = −12→12 |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | k = −8→8 |
Tmin = 0.291, Tmax = 0.384 | l = −22→22 |
14301 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.020 | H-atom parameters constrained |
wR(F2) = 0.049 | w = 1/[σ2(Fo2) + (0.0201P)2 + 0.702P] where P = (Fo2 + 2Fc2)/3 |
S = 1.03 | (Δ/σ)max = 0.002 |
2378 reflections | Δρmax = 0.51 e Å−3 |
128 parameters | Δρmin = −0.35 e Å−3 |
0 restraints | Extinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0122 (5) |
C12H8Br2 | V = 1041.3 (5) Å3 |
Mr = 312.00 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 9.520 (3) Å | µ = 7.74 mm−1 |
b = 6.5032 (18) Å | T = 173 K |
c = 17.124 (5) Å | 0.21 × 0.16 × 0.15 mm |
β = 100.826 (3)° |
Bruker APEXII CCD area-detector diffractometer | 2378 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | 2076 reflections with I > 2σ(I) |
Tmin = 0.291, Tmax = 0.384 | Rint = 0.029 |
14301 measured reflections |
R[F2 > 2σ(F2)] = 0.020 | 0 restraints |
wR(F2) = 0.049 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.51 e Å−3 |
2378 reflections | Δρmin = −0.35 e Å−3 |
128 parameters |
Experimental. A crystal coated in Paratone (TM) oil was mounted on the end of a thin glass capillary and cooled in the gas stream of the diffractometer Kryoflex 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. |
x | y | z | Uiso*/Ueq | ||
Br1 | 0.95694 (2) | 1.00116 (3) | 0.877281 (12) | 0.03051 (8) | |
Br2 | 0.91366 (2) | 0.51805 (3) | 0.782113 (12) | 0.02895 (8) | |
C1 | 0.7083 (2) | 0.4723 (3) | 0.89091 (11) | 0.0248 (4) | |
H1 | 0.6971 | 0.3347 | 0.8644 | 0.030* | |
C2 | 0.57169 (19) | 0.6026 (3) | 0.87439 (10) | 0.0228 (4) | |
C3 | 0.4419 (2) | 0.5494 (3) | 0.82843 (12) | 0.0299 (4) | |
H3 | 0.4291 | 0.4189 | 0.8032 | 0.036* | |
C4 | 0.3293 (2) | 0.6909 (4) | 0.81956 (12) | 0.0355 (5) | |
H4 | 0.2387 | 0.6550 | 0.7891 | 0.043* | |
C5 | 0.3489 (2) | 0.8822 (4) | 0.85474 (11) | 0.0329 (5) | |
H5 | 0.2721 | 0.9779 | 0.8473 | 0.039* | |
C6 | 0.4807 (2) | 0.9370 (3) | 0.90125 (11) | 0.0268 (4) | |
H6 | 0.4944 | 1.0689 | 0.9253 | 0.032* | |
C7 | 0.59055 (19) | 0.7949 (3) | 0.91135 (10) | 0.0216 (4) | |
C8 | 0.74157 (19) | 0.8223 (3) | 0.95989 (10) | 0.0222 (4) | |
H8 | 0.7566 | 0.9586 | 0.9872 | 0.027* | |
C9 | 0.83973 (18) | 0.7872 (3) | 0.89981 (11) | 0.0217 (4) | |
C10 | 0.82213 (18) | 0.6069 (3) | 0.86406 (11) | 0.0222 (4) | |
C11 | 0.7486 (2) | 0.4593 (3) | 0.98174 (12) | 0.0287 (4) | |
H11 | 0.7602 | 0.3326 | 1.0098 | 0.034* | |
C12 | 0.7658 (2) | 0.6398 (3) | 1.01740 (11) | 0.0279 (4) | |
H12 | 0.7908 | 0.6551 | 1.0735 | 0.033* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.02660 (12) | 0.02868 (12) | 0.03774 (13) | −0.00821 (7) | 0.00988 (9) | 0.00147 (8) |
Br2 | 0.03114 (12) | 0.03011 (12) | 0.02878 (12) | 0.00309 (7) | 0.01384 (8) | −0.00166 (7) |
C1 | 0.0276 (9) | 0.0201 (8) | 0.0284 (10) | −0.0030 (7) | 0.0098 (8) | −0.0022 (7) |
C2 | 0.0233 (9) | 0.0277 (9) | 0.0196 (8) | −0.0045 (7) | 0.0095 (7) | 0.0004 (7) |
C3 | 0.0280 (10) | 0.0386 (10) | 0.0242 (9) | −0.0105 (8) | 0.0076 (8) | −0.0032 (8) |
C4 | 0.0228 (10) | 0.0597 (14) | 0.0239 (10) | −0.0064 (9) | 0.0046 (8) | 0.0036 (9) |
C5 | 0.0243 (9) | 0.0515 (13) | 0.0247 (10) | 0.0086 (9) | 0.0095 (8) | 0.0073 (9) |
C6 | 0.0285 (9) | 0.0326 (10) | 0.0222 (9) | 0.0029 (8) | 0.0122 (8) | 0.0025 (8) |
C7 | 0.0227 (9) | 0.0270 (9) | 0.0169 (8) | −0.0021 (7) | 0.0082 (7) | 0.0017 (7) |
C8 | 0.0236 (9) | 0.0226 (9) | 0.0213 (9) | −0.0016 (7) | 0.0065 (7) | −0.0024 (7) |
C9 | 0.0176 (8) | 0.0242 (9) | 0.0234 (9) | −0.0024 (7) | 0.0043 (7) | 0.0033 (7) |
C10 | 0.0206 (8) | 0.0252 (9) | 0.0223 (9) | 0.0030 (7) | 0.0076 (7) | 0.0019 (7) |
C11 | 0.0318 (10) | 0.0286 (10) | 0.0268 (10) | 0.0002 (8) | 0.0085 (8) | 0.0069 (8) |
C12 | 0.0286 (10) | 0.0337 (10) | 0.0214 (9) | −0.0015 (8) | 0.0048 (8) | 0.0047 (8) |
Br1—C9 | 1.8687 (18) | C5—C6 | 1.400 (3) |
Br2—C10 | 1.8766 (18) | C5—H5 | 0.9500 |
C1—C10 | 1.530 (2) | C6—C7 | 1.382 (3) |
C1—C11 | 1.533 (3) | C6—H6 | 0.9500 |
C1—C2 | 1.533 (3) | C7—C8 | 1.530 (2) |
C1—H1 | 1.0000 | C8—C9 | 1.531 (2) |
C2—C3 | 1.379 (3) | C8—C12 | 1.532 (3) |
C2—C7 | 1.398 (3) | C8—H8 | 1.0000 |
C3—C4 | 1.399 (3) | C9—C10 | 1.318 (3) |
C3—H3 | 0.9500 | C11—C12 | 1.319 (3) |
C4—C5 | 1.380 (3) | C11—H11 | 0.9500 |
C4—H4 | 0.9500 | C12—H12 | 0.9500 |
C10—C1—C11 | 106.24 (15) | C6—C7—C2 | 120.79 (17) |
C10—C1—C2 | 104.60 (14) | C6—C7—C8 | 126.99 (17) |
C11—C1—C2 | 105.06 (15) | C2—C7—C8 | 112.22 (15) |
C10—C1—H1 | 113.4 | C7—C8—C9 | 104.32 (14) |
C11—C1—H1 | 113.4 | C7—C8—C12 | 105.75 (14) |
C2—C1—H1 | 113.4 | C9—C8—C12 | 106.20 (14) |
C3—C2—C7 | 120.53 (18) | C7—C8—H8 | 113.3 |
C3—C2—C1 | 127.22 (17) | C9—C8—H8 | 113.3 |
C7—C2—C1 | 112.25 (15) | C12—C8—H8 | 113.3 |
C2—C3—C4 | 118.90 (19) | C10—C9—C8 | 113.85 (15) |
C2—C3—H3 | 120.5 | C10—C9—Br1 | 126.50 (14) |
C4—C3—H3 | 120.5 | C8—C9—Br1 | 119.41 (13) |
C5—C4—C3 | 120.51 (18) | C9—C10—C1 | 113.88 (16) |
C5—C4—H4 | 119.7 | C9—C10—Br2 | 125.79 (14) |
C3—C4—H4 | 119.7 | C1—C10—Br2 | 120.20 (13) |
C4—C5—C6 | 120.73 (19) | C12—C11—C1 | 114.00 (17) |
C4—C5—H5 | 119.6 | C12—C11—H11 | 123.0 |
C6—C5—H5 | 119.6 | C1—C11—H11 | 123.0 |
C7—C6—C5 | 118.50 (19) | C11—C12—C8 | 113.66 (17) |
C7—C6—H6 | 120.7 | C11—C12—H12 | 123.2 |
C5—C6—H6 | 120.7 | C8—C12—H12 | 123.2 |
C10—C1—C2—C3 | 123.85 (19) | C2—C7—C8—C12 | −54.79 (19) |
C11—C1—C2—C3 | −124.47 (19) | C7—C8—C9—C10 | −57.17 (19) |
C10—C1—C2—C7 | −55.32 (19) | C12—C8—C9—C10 | 54.3 (2) |
C11—C1—C2—C7 | 56.35 (18) | C7—C8—C9—Br1 | 117.51 (14) |
C7—C2—C3—C4 | −0.1 (3) | C12—C8—C9—Br1 | −131.03 (13) |
C1—C2—C3—C4 | −179.24 (17) | C8—C9—C10—C1 | −0.4 (2) |
C2—C3—C4—C5 | 1.5 (3) | Br1—C9—C10—C1 | −174.62 (13) |
C3—C4—C5—C6 | −1.3 (3) | C8—C9—C10—Br2 | 175.36 (12) |
C4—C5—C6—C7 | −0.2 (3) | Br1—C9—C10—Br2 | 1.1 (2) |
C5—C6—C7—C2 | 1.6 (3) | C11—C1—C10—C9 | −53.6 (2) |
C5—C6—C7—C8 | −179.54 (17) | C2—C1—C10—C9 | 57.3 (2) |
C3—C2—C7—C6 | −1.4 (3) | C11—C1—C10—Br2 | 130.43 (14) |
C1—C2—C7—C6 | 177.83 (16) | C2—C1—C10—Br2 | −118.75 (14) |
C3—C2—C7—C8 | 179.56 (16) | C10—C1—C11—C12 | 53.9 (2) |
C1—C2—C7—C8 | −1.2 (2) | C2—C1—C11—C12 | −56.6 (2) |
C6—C7—C8—C9 | −121.96 (19) | C1—C11—C12—C8 | 0.0 (2) |
C2—C7—C8—C9 | 57.00 (18) | C7—C8—C12—C11 | 56.5 (2) |
C6—C7—C8—C12 | 126.26 (19) | C9—C8—C12—C11 | −54.0 (2) |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | C12H10Br4 | C12H8Br2 |
Mr | 473.84 | 312.00 |
Crystal system, space group | Triclinic, P1 | Monoclinic, P21/n |
Temperature (K) | 173 | 173 |
a, b, c (Å) | 6.9532 (4), 8.4323 (5), 11.9669 (7) | 9.520 (3), 6.5032 (18), 17.124 (5) |
α, β, γ (°) | 94.706 (1), 91.257 (1), 110.892 (1) | 90, 100.826 (3), 90 |
V (Å3) | 652.31 (7) | 1041.3 (5) |
Z | 2 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 12.31 | 7.74 |
Crystal size (mm) | 0.45 × 0.27 × 0.27 | 0.21 × 0.16 × 0.15 |
Data collection | ||
Diffractometer | Bruker APEXII CCD area-detector diffractometer | Bruker APEXII CCD area-detector diffractometer |
Absorption correction | Numerical (SADABS; Bruker, 2008) | Multi-scan (SADABS; Bruker, 2008) |
Tmin, Tmax | 0.052, 0.144 | 0.291, 0.384 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 7682, 3074, 2835 | 14301, 2378, 2076 |
Rint | 0.024 | 0.029 |
(sin θ/λ)max (Å−1) | 0.666 | 0.649 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.022, 0.055, 1.05 | 0.020, 0.049, 1.03 |
No. of reflections | 3074 | 2378 |
No. of parameters | 146 | 128 |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.78, −0.78 | 0.51, −0.35 |
Computer programs: APEX2 (Bruker, 2008), SAINT-Plus (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), Mercury (Macrae et al., 2008), publCIF (Westrip, 2010).
We recently reported the crystal and molecular structure of the useful intermediate 3,4-dibromo-6,7-benzobicyclo[3.2.1]octa-2,6-diene, (III) (Johnson et al., 2011) (Scheme 1). We report here on two related structures which provide access to a variety of substituted benzobarrelenes (Çakmak & Balcı, 1989; Bender et al., 2003). Compound (I) (Fig. 1) is formed by the addition of bromine to (III) and is the direct precursor, by double dehydrobromination, of the extremely useful compound (II) (Fig. 2). We have used (II), inter alia, in the preparation of specifically labelled deuterated species such as 2-bromo-3-deuteriobenzobarrelene (Bender et al., 2003).
The crystal structure of (I) is the first reported for any tetrabromo derivative of the 1,2,3,4-tetrahydro-1,4-ethanonaphthalene framework. Structures are known for two tribromides, (1RS,4SR,10SR)-2,2,10-tribromo-1,2,3,4-tetrahydro-1,4-ethanonaphthalene, (IV) [Cambridge Structural Database (CSD; Allen, 2002) refcode FOMREE (Ergin et al., 1987)] (Scheme 2) and (1RS,3SR,4SR)-2,2,3-tribromo-1,2,3,4-tetrahydro-1,4-ethanonaphthalene, (V) (refcode KAKVEZ; Eşsiz et al., 2011). Thus, (IV) lacks the Br at position 3, whilst (V) lacks that at position 10 compared with (I). Note that both of the variable Br-atom locations are in the exo position.
There are two reported structures for pentabromide isomers, (1SR,3RS,4RS,9SR,10RS)-2,2,3,9,10-pentabromo-1,2,3,4-tetrahydro-1,4-ethanonaphthalene, (VI) (refcode MOCWUW; Ülkü et al., 2002) and (1SR,3SR,4RS,9SR,10RS)-2,2,3,9,10-pentabromo-1,2,3,4-tetrahydro-1,4-ethanonaphthalene, (VII) (refcode TAFXIH; Hökelek et al., 1990). The latter two differ, respectively, in the endo versus exo orientation of the Br atom at position 3. The geometry of the parent hydrocarbon framework without substituents on the bicyclic cage is available in 5,8-diacetoxy-1,2,3,4-tetrahydro-1,4-ethanonaphthalene, (VIII) (refcode EDAGUM; Goh et al., 2007), and in the structure of a cocrystal of 5,6,7,8-tetramethyl-1,2,3,4-tetrahydro-1,4-ethanonaphthalene, (IX) (refcode PAWDIA; Rathore et al., 1998). In (IV)–(IX), the two single bonds attached to benzene [equivalent to C1—C2 and C7—C8 in (I)] average 1.505 (9) Å, a value not statistically different from the average value in (I) of 1.517 (6) Å. However, these bonds appear shorter than the remaining cage bonds at the 95% confidence level; the latter have a mean value in (IV)–(IX) of 1.544 (10) Å, once the lowest outliers in Fig. 3 are omitted. The mean value for these bonds in (I) of 1.545 (5) Å represents a very good match. Over all seven structures, there appears to be a slight trend towards longer C—C distances for those bonds substituted with two Br atoms at one end and one Br atom at the other, which average 1.558 (9) Å, but the difference from the distribution shown in Fig. 3 is not statistically significant for this sample.
If the conformation around the boat cyclohexane ring (atoms C1, C10, C9, C8, C12 and C11) is considered, (I) is the most distorted of this comparison set from the essentially pure boat conformations observed in (VIII) and (XI) [even though (VI) and (VII) are pentabromides]. This may be a consequence of it being the only example with three exo Br atoms, arranged in an 1,2,4 all-axial substitution pattern around this saturated six-membered ring. Thus, the torsion angles at the ethane bridges of 18.8 (2) (Br1—C9—C10—Br2) and 35.3 (2)° (Br4—C11—C12—H12A) in (I) are considerably larger than in the comparison set. Visually, this ring is also distorted in (IV). A Cremer & Pople conformational analysis (Cremer & Pople, 1975) for (I), undertaken using PLATON (Spek, 2009), results in puckering parameters of Q = 0.829 (3) Å, θ = 92.8 (2)° and ϕ = 19.24 (19)° for the C1/C10/C9/C8/C12/C11 ring, whereas for (IV), Q = 0.823 (16) Å, θ = 94.3(s.u.?)° and ϕ = 7.4 (11)° for the C10/C12/C11/C7/C8/C9 ring. Thus, the conformation in (I) is intermediate but closer to the twist-boat limit (ϕ = 0° for boat and 30° for twisted), whereas that in (IV) is much closer to boat.
The molecules of (I) lack any symmetry and stack along the a axis of the unit cell, with short Br3···C4ii contacts of 3.430 (3) Å. However, the strongest interaction is probably between atom Br3 and the benzene ring centroid [3.332 (3) Å] (see Fig. 4 for symmetry code).
To date, no crystal structures have been reported for any derivatives of a mono-fused bicyclo[2.2.2]octa-1(7),4(8),5-triene (i.e. a benzobarrelene) bearing halogen substituents on the framework atoms. Indeed, a search of the CSD (WebCSD December 2012) returned only seven structures for this class of compound (excluding metal complexes). Of these, the examples with electron-withdrawing substituents that might be most comparable with (II) are methyl 2-benzoyl-1,4-dihydro-1,4-ethenonaphthalene-3-carboxylate, (X) (refcode LEKLAO; Pokkuluri, Scheffer, Trotter & Yap, 1994), dimethyl 7,8-benzobicyclo[2.2.2]octa-2,5,7-triene-2,3-dicarboxylate, (XI) (refcode SATPUY; Trotter, 1989), and dimethyl 9-phenyl-1,4-dihydro-1,4-ethenoanthracene-11,12-dicarboxylate, (XII) (refcode WEJBOC; Pokkuluri, Scheffer, & Trotter, 1994). In this sample of four structures, the single bonds of the barrelenes are indistinguishable, with an average length of 1.526 (9) Å. Interestingly, for the nonfused C═C bonds, those in (II) fit best with the `unsubstituted' analogues, at an average distance of 1.315 (4) Å, whereas the C═C bonds bearing the ester or ketone substituents in (X)–(XII) are longer at an average of 1.337 (6) Å, suggesting that in these cases there is steric congestion resulting from the 1,2-substitution of the carbonyl groups. And yet the Br atoms in (II) seem to cause little crowding; the intramolecular Br1···Br2 contact distance is 3.5276 (8) Å, only marginally less than the sums of their van der Waals radii [Standard reference?]. Whilst it is true that the C10—C9—Br1 [126.50 (14)°] and C9—C10—Br2 [125.79 (14)°] angles are wide, this is just as likely to be a consequence of the pinching of the interior angles at atoms C9 and C10 by the bicyclic cage geometry as to be due to steric pressure between the Br atoms.
Molecules of (II) possess approximate point symmetry m. Short intermolecular Br2···C6i contacts [3.512 (2) Å] link them into a zigzag chain parallel to the crystallographic b axis (see Fig. 5 for symmetry codes). Here too, just as in (I), the strongest interaction is between Br and neighbouring benzene ring centroids, at 3.480 (3) Å.