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The title compound, C
12H
22Br
2, displays crystallographic inversion symmetry. Bond lengths C=C = 1.352 (4) Å and C
sp2—C
sp3 = 1.574 (3) Å are interpreted as symptoms of steric overcrowding. Molecules are linked into chains parallel to [101] by Br
Br interactions of 3.4275 (9) Å.
Supporting information
CCDC reference: 605238
Key indicators
- Single-crystal X-ray study
- T = 173 K
- Mean (C-C) = 0.003 Å
- R factor = 0.027
- wR factor = 0.068
- Data-to-parameter ratio = 21.2
checkCIF/PLATON results
No syntax errors found
Alert level B
PLAT061_ALERT_3_B Tmax/Tmin Range Test RR' too Large ............. 0.63
Alert level C
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given ....... ?
PLAT412_ALERT_2_C Short Intra XH3 .. XHn H3A .. H6B .. 1.89 Ang.
PLAT431_ALERT_2_C Short Inter HL..A Contact Br .. Br .. 3.43 Ang.
0 ALERT level A = In general: serious problem
1 ALERT level B = Potentially serious problem
3 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
2 ALERT type 2 Indicator that the structure model may be wrong or deficient
1 ALERT type 3 Indicator that the structure quality may be low
1 ALERT type 4 Improvement, methodology, query or suggestion
Data collection: DIF4 (Stoe & Cie, 1992); cell refinement: DIF4; data reduction: REDU4 (Stoe & Cie, 1992); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1994); software used to prepare material for publication: SHELXL97.
(
E)-3,4-bis(bromomethyl)-2,2,5,5-tetramethylhex-3-ene
top
Crystal data top
C12H22Br2 | F(000) = 656 |
Mr = 326.12 | Dx = 1.671 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 15.658 (4) Å | Cell parameters from 60 reflections |
b = 7.3521 (12) Å | θ = 10–11.5° |
c = 11.284 (2) Å | µ = 6.22 mm−1 |
β = 93.53 (2)° | T = 173 K |
V = 1296.6 (5) Å3 | Block, colourless |
Z = 4 | 0.5 × 0.4 × 0.4 mm |
Data collection top
Stoe STADI4 diffractometer | 1341 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.035 |
Graphite monochromator | θmax = 27.5°, θmin = 3.1° |
ω/θ scans | h = −20→20 |
Absorption correction: ψ scan (XEMP; Siemens, 1994) | k = −9→4 |
Tmin = 0.035, Tmax = 0.083 | l = 0→14 |
2458 measured reflections | 3 standard reflections every 60 min |
1487 independent reflections | intensity decay: none |
Refinement top
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)] = 0.027 | H-atom parameters constrained |
wR(F2) = 0.068 | w = 1/[σ2(Fo2) + (0.0302P)2 + 1.7902P] where P = (Fo2 + 2Fc2)/3 |
S = 1.10 | (Δ/σ)max = 0.001 |
1487 reflections | Δρmax = 0.60 e Å−3 |
70 parameters | Δρmin = −0.57 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0023 (4) |
Special details top
Experimental. MS (70 eV): m/z (%) = 328 (3), 326 (6), 324 (3) [M+], 247
(5), 245 (5), 83 (100), 58 (78) |
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 | x | y | z | Uiso*/Ueq | |
Br | 0.435600 (14) | 0.11695 (4) | 0.62158 (2) | 0.03111 (13) | |
C1 | 0.28891 (12) | 0.2506 (3) | 0.47719 (17) | 0.0142 (4) | |
C2 | 0.32972 (14) | 0.4144 (3) | 0.41075 (19) | 0.0173 (4) | |
C3 | 0.27146 (15) | 0.4888 (3) | 0.3070 (2) | 0.0246 (5) | |
H3A | 0.2252 | 0.5606 | 0.3384 | 0.030* | |
H3B | 0.2470 | 0.3872 | 0.2600 | 0.030* | |
H3C | 0.3051 | 0.5660 | 0.2566 | 0.030* | |
C4 | 0.35479 (16) | 0.5664 (3) | 0.4995 (2) | 0.0255 (5) | |
H4A | 0.3948 | 0.5184 | 0.5620 | 0.031* | |
H4B | 0.3034 | 0.6121 | 0.5352 | 0.031* | |
H4C | 0.3821 | 0.6659 | 0.4581 | 0.031* | |
C5 | 0.41272 (16) | 0.3583 (3) | 0.3529 (2) | 0.0263 (5) | |
H5A | 0.4536 | 0.3086 | 0.4138 | 0.032* | |
H5B | 0.4378 | 0.4651 | 0.3163 | 0.032* | |
H5C | 0.3994 | 0.2658 | 0.2921 | 0.032* | |
C6 | 0.34563 (14) | 0.0873 (3) | 0.49072 (19) | 0.0179 (4) | |
H6A | 0.3732 | 0.0658 | 0.4154 | 0.022 (7)* | |
H6B | 0.3104 | −0.0207 | 0.5068 | 0.027 (7)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Br | 0.01868 (16) | 0.04656 (19) | 0.02728 (17) | 0.00689 (9) | −0.00526 (10) | 0.00523 (10) |
C1 | 0.0149 (9) | 0.0148 (9) | 0.0125 (9) | −0.0003 (7) | −0.0011 (7) | −0.0007 (7) |
C2 | 0.0151 (10) | 0.0186 (10) | 0.0188 (10) | −0.0017 (8) | 0.0057 (8) | 0.0005 (8) |
C3 | 0.0281 (11) | 0.0265 (11) | 0.0197 (11) | 0.0022 (9) | 0.0043 (9) | 0.0079 (9) |
C4 | 0.0264 (12) | 0.0223 (11) | 0.0282 (12) | −0.0073 (9) | 0.0052 (10) | −0.0052 (9) |
C5 | 0.0205 (11) | 0.0324 (12) | 0.0269 (12) | −0.0007 (9) | 0.0091 (10) | 0.0038 (10) |
C6 | 0.0151 (10) | 0.0197 (10) | 0.0188 (10) | 0.0020 (8) | 0.0005 (8) | 0.0014 (8) |
Geometric parameters (Å, º) top
Br—C6 | 1.989 (2) | C3—H3C | 0.9800 |
C1—C1i | 1.352 (4) | C4—H4A | 0.9800 |
C1—C6 | 1.495 (3) | C4—H4B | 0.9800 |
C1—C2 | 1.574 (3) | C4—H4C | 0.9800 |
C2—C4 | 1.536 (3) | C5—H5A | 0.9800 |
C2—C3 | 1.540 (3) | C5—H5B | 0.9800 |
C2—C5 | 1.546 (3) | C5—H5C | 0.9800 |
C3—H3A | 0.9800 | C6—H6A | 0.9900 |
C3—H3B | 0.9800 | C6—H6B | 0.9900 |
| | | |
C1i—C1—C6 | 120.0 (2) | C2—C4—H4B | 109.5 |
C1i—C1—C2 | 126.0 (2) | H4A—C4—H4B | 109.5 |
C6—C1—C2 | 113.99 (17) | C2—C4—H4C | 109.5 |
C4—C2—C3 | 110.66 (19) | H4A—C4—H4C | 109.5 |
C4—C2—C5 | 106.36 (18) | H4B—C4—H4C | 109.5 |
C3—C2—C5 | 104.35 (18) | C2—C5—H5A | 109.5 |
C4—C2—C1 | 109.93 (18) | C2—C5—H5B | 109.5 |
C3—C2—C1 | 113.28 (18) | H5A—C5—H5B | 109.5 |
C5—C2—C1 | 111.94 (17) | C2—C5—H5C | 109.5 |
C1—C6—Br | 112.14 (14) | H5A—C5—H5C | 109.5 |
C2—C3—H3A | 109.5 | H5B—C5—H5C | 109.5 |
C2—C3—H3B | 109.5 | C1—C6—H6A | 109.2 |
H3A—C3—H3B | 109.5 | Br—C6—H6A | 109.2 |
C2—C3—H3C | 109.5 | C1—C6—H6B | 109.2 |
H3A—C3—H3C | 109.5 | Br—C6—H6B | 109.2 |
H3B—C3—H3C | 109.5 | H6A—C6—H6B | 107.9 |
C2—C4—H4A | 109.5 | | |
| | | |
C1i—C1—C2—C4 | 71.3 (3) | C6—C1—C2—C5 | 10.9 (3) |
C6—C1—C2—C4 | −107.1 (2) | C1i—C1—C6—Br | −100.3 (3) |
C1i—C1—C2—C3 | −53.1 (3) | C2—C1—C6—Br | 78.20 (19) |
C6—C1—C2—C3 | 128.51 (19) | C6—C1—C1i—C2i | −1.7 (4) |
C1i—C1—C2—C5 | −170.7 (3) | | |
Symmetry code: (i) −x+1/2, −y+1/2, −z+1. |
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