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The molecule of the title compound, C20H40Br2, is centrosymmetric and the skeleton has an all-trans conformation including both terminal Br atoms. In the crystal structure, the molecules form a layer in which the long axes of the molecules are inclined to the basal plane of the Br atoms. The layers are arranged in a zigzag manner between the neighboring layers, forming a herringbone motif, just like the smectic CA phase of liquid crystals.
Supporting information
CCDC reference: 248843
Key indicators
- Single-crystal X-ray study
- T = 296 K
- Mean (C-C) = 0.005 Å
- R factor = 0.038
- wR factor = 0.116
- Data-to-parameter ratio = 16.6
checkCIF/PLATON results
No syntax errors found
Alert level B
PLAT029_ALERT_3_B _diffrn_measured_fraction_theta_full Low ....... 0.95
0 ALERT level A = In general: serious problem
1 ALERT level B = Potentially serious problem
0 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
0 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
0 ALERT type 4 Improvement, methodology, query or suggestion
Data collection: MSC/AFC Diffractometer Control Software
(Molecular Structure Coorporation, 1992); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: CrystalStructure (Molecular Structure Coorporation & Rigaku, 2001); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: CRYSTALS (Watkin et al., 1996); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: CrystalStructure.
Crystal data top
C20H40Br2 | F(000) = 460.00 |
Mr = 440.34 | Dx = 1.325 Mg m−3 |
Monoclinic, P21/n | Cu Kα radiation, λ = 1.5418 Å |
Hall symbol: -P 2yn | Cell parameters from 24 reflections |
a = 5.482 (4) Å | θ = 9.5–15.5° |
b = 5.383 (2) Å | µ = 4.61 mm−1 |
c = 37.412 (2) Å | T = 296 K |
β = 91.50 (2)° | Plate, colorless |
V = 1103.6 (9) Å3 | 0.59 × 0.47 × 0.04 mm |
Z = 2 | |
Data collection top
Rigaku AFC-5R diffractometer | Rint = 0.028 |
ω–2θ scans | θmax = 70.1° |
Absorption correction: integration (NUMABS; Higashi, 1997) | h = −1→6 |
Tmin = 0.325, Tmax = 0.997 | k = 0→6 |
3004 measured reflections | l = −45→45 |
2008 independent reflections | 3 standard reflections every 150 reflections |
1667 reflections with F2 > 2σ(F2) | intensity decay: 6.8% |
Refinement top
Refinement on F2 | w = 1/[0.001Fo2 + 5.3σ2(Fo) + 0.52]/(4Fo2) |
R[F2 > 2σ(F2)] = 0.038 | (Δ/σ)max < 0.001 |
wR(F2) = 0.116 | Δρmax = 0.38 e Å−3 |
S = 1.00 | Δρmin = −0.62 e Å−3 |
2008 reflections | Extinction correction: (Larson, 1970) |
121 parameters | Extinction coefficient: 21.3 (3) |
H-atom parameters constrained | |
Special details top
Geometry. ENTER SPECIAL DETAILS OF THE MOLECULAR GEOMETRY |
Refinement. Refinement using reflections with F2 > -3.0 σ(F2). The
weighted R-factor (wR) and goodness of fit (S) are based
on F2. R-factor (gt) are based on F. The threshold
expression of F2 > 2.0 σ(F2) is used only for calculating
R-factor (gt). |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Br1 | 2.10859 (8) | 1.11565 (8) | 0.77760 (1) | 0.0745 (2) | |
C1 | 1.9280 (8) | 0.8210 (8) | 0.7914 (1) | 0.073 (1) | |
C2 | 1.7723 (7) | 0.8642 (7) | 0.8228 (1) | 0.064 (1) | |
C3 | 1.6346 (7) | 0.6328 (7) | 0.83329 (9) | 0.063 (1) | |
C4 | 1.4761 (8) | 0.6735 (7) | 0.8657 (1) | 0.064 (1) | |
C5 | 1.3358 (7) | 0.4444 (7) | 0.87653 (9) | 0.060 (1) | |
C6 | 1.1766 (7) | 0.4850 (7) | 0.90874 (9) | 0.062 (1) | |
C7 | 1.0317 (7) | 0.2594 (7) | 0.91933 (9) | 0.061 (1) | |
C8 | 0.8758 (7) | 0.2971 (7) | 0.95168 (9) | 0.061 (1) | |
C9 | 0.7299 (7) | 0.0727 (7) | 0.96236 (9) | 0.062 (1) | |
C10 | 0.5733 (7) | 0.1120 (6) | 0.99475 (9) | 0.061 (1) | |
H1 | 1.8282 | 0.7683 | 0.7716 | 0.088* | |
H2 | 2.0414 | 0.6936 | 0.7975 | 0.088* | |
H3 | 1.6561 | 0.9890 | 0.8166 | 0.077* | |
H4 | 1.8708 | 0.9190 | 0.8425 | 0.077* | |
H5 | 1.5351 | 0.5787 | 0.81363 | 0.075* | |
H6 | 1.7508 | 0.5076 | 0.83929 | 0.075* | |
H7 | 1.3606 | 0.7992 | 0.8597 | 0.077* | |
H8 | 1.5760 | 0.7274 | 0.8854 | 0.077* | |
H9 | 1.2352 | 0.3908 | 0.85695 | 0.073* | |
H10 | 1.4512 | 0.3184 | 0.88247 | 0.073* | |
H11 | 1.0645 | 0.6145 | 0.90300 | 0.075* | |
H12 | 1.2778 | 0.5341 | 0.92850 | 0.075* | |
H13 | 0.9302 | 0.2112 | 0.89956 | 0.074* | |
H14 | 1.1443 | 0.1299 | 0.92486 | 0.074* | |
H15 | 0.7632 | 0.4265 | 0.94610 | 0.073* | |
H16 | 0.9775 | 0.3459 | 0.97140 | 0.073* | |
H17 | 0.6283 | 0.0234 | 0.94266 | 0.074* | |
H18 | 0.8421 | −0.0567 | 0.96807 | 0.074* | |
H19 | 0.4612 | 0.2418 | 0.98921 | 0.074* | |
H20 | 0.6743 | 0.1594 | 1.01461 | 0.074* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Br1 | 0.0855 (4) | 0.0635 (3) | 0.0758 (3) | −0.0095 (2) | 0.0281 (2) | 0.0029 (2) |
C1 | 0.091 (3) | 0.064 (2) | 0.064 (2) | −0.007 (2) | 0.027 (2) | −0.003 (2) |
C2 | 0.071 (2) | 0.060 (2) | 0.060 (2) | −0.006 (2) | 0.017 (2) | −0.001 (2) |
C3 | 0.072 (2) | 0.062 (2) | 0.055 (2) | −0.009 (2) | 0.016 (2) | 0.000 (2) |
C4 | 0.072 (2) | 0.061 (2) | 0.059 (2) | −0.003 (2) | 0.017 (2) | 0.000 (2) |
C5 | 0.070 (2) | 0.059 (2) | 0.053 (2) | −0.007 (2) | 0.016 (2) | 0.001 (2) |
C6 | 0.071 (2) | 0.061 (2) | 0.054 (2) | −0.007 (2) | 0.016 (2) | −0.001 (2) |
C7 | 0.070 (2) | 0.062 (2) | 0.053 (2) | −0.009 (2) | 0.016 (2) | −0.000 (2) |
C8 | 0.071 (2) | 0.060 (2) | 0.053 (2) | −0.007 (2) | 0.016 (2) | −0.002 (2) |
C9 | 0.073 (2) | 0.061 (2) | 0.052 (2) | −0.005 (2) | 0.016 (2) | −0.002 (2) |
C10 | 0.073 (2) | 0.060 (2) | 0.052 (2) | −0.007 (2) | 0.017 (2) | −0.000 (2) |
Geometric parameters (Å, º) top
Br1—C1 | 1.946 (4) | C3—H6 | 0.950 |
C1—C2 | 1.489 (5) | C4—H7 | 0.950 |
C2—C3 | 1.514 (5) | C4—H8 | 0.95 |
C3—C4 | 1.526 (5) | C5—H9 | 0.95 |
C4—C5 | 1.514 (5) | C5—H10 | 0.950 |
C5—C6 | 1.522 (4) | C6—H11 | 0.950 |
C6—C7 | 1.510 (5) | C6—H12 | 0.95 |
C7—C8 | 1.514 (4) | C7—H13 | 0.95 |
C8—C9 | 1.509 (5) | C7—H14 | 0.950 |
C9—C10 | 1.518 (4) | C8—H15 | 0.950 |
C10—C10i | 1.507 (5) | C8—H16 | 0.95 |
C1—H1 | 0.95 | C9—H17 | 0.95 |
C1—H2 | 0.950 | C9—H18 | 0.950 |
C2—H3 | 0.950 | C10—H19 | 0.950 |
C2—H4 | 0.95 | C10—H20 | 0.95 |
C3—H5 | 0.95 | | |
| | | |
Br1···Br1ii | 3.752 (3) | Br1···Br1iii | 3.752 (3) |
| | | |
Br1—C1—C2 | 112.8 (3) | C6—C5—H9 | 108.7 |
C1—C2—C3 | 112.1 (3) | C4—C5—H10 | 107.7 |
C2—C3—C4 | 112.7 (3) | C6—C5—H10 | 108.0 |
C3—C4—C5 | 113.5 (3) | H9—C5—H10 | 109.5 |
C4—C5—C6 | 113.6 (3) | C5—C6—H11 | 107.9 |
C5—C6—C7 | 114.1 (3) | C7—C6—H11 | 107.9 |
C6—C7—C8 | 114.4 (3) | C5—C6—H12 | 108.7 |
C7—C8—C9 | 114.7 (3) | C7—C6—H12 | 108.7 |
C8—C9—C10 | 114.5 (3) | H11—C6—H12 | 109.5 |
C9—C10—C10i | 114.4 (3) | C6—C7—H13 | 108.5 |
C2—C1—H1 | 109.2 | C8—C7—H13 | 109.1 |
Br1—C1—H2 | 108.6 | C6—C7—H14 | 107.7 |
C2—C1—H2 | 107.8 | C8—C7—H14 | 107.6 |
H1—C1—H2 | 109.5 | H13—C7—H14 | 109.5 |
C1—C2—H3 | 108.2 | C7—C8—H15 | 107.5 |
C3—C2—H3 | 108.0 | C9—C8—H15 | 107.4 |
C1—C2—H4 | 109.7 | C7—C8—H16 | 109.0 |
C3—C2—H4 | 109.3 | C9—C8—H16 | 108.7 |
H3—C2—H4 | 109.5 | H15—C8—H16 | 109.5 |
C2—C3—H5 | 109.4 | C8—C9—H17 | 108.8 |
C4—C3—H5 | 109.4 | C10—C9—H17 | 109.0 |
C2—C3—H6 | 108.0 | C8—C9—H18 | 107.6 |
C4—C3—H6 | 107.8 | C10—C9—H18 | 107.4 |
H5—C3—H6 | 109.5 | H17—C9—H18 | 109.5 |
C3—C4—H7 | 107.7 | C9—C10—H19 | 107.7 |
C5—C4—H7 | 107.6 | C10i—C10—H19 | 107.4 |
C3—C4—H8 | 109.3 | C9—C10—H20 | 109.4 |
C5—C4—H8 | 109.2 | C10i—C10—H20 | 108.4 |
H7—C4—H8 | 109.5 | H19—C10—H20 | 109.5 |
C4—C5—H9 | 109.3 | | |
| | | |
Br1—C1—C2—C3 | −179.6 (2) | C5—C6—C7—C8 | 179.2 (3) |
C1—C2—C3—C4 | 179.4 (3) | C6—C7—C8—C9 | 179.8 (3) |
C2—C3—C4—C5 | 179.7 (3) | C7—C8—C9—C10 | −179.8 (3) |
C3—C4—C5—C6 | −179.7 (3) | C8—C9—C10—C10i | 179.7 (3) |
C4—C5—C6—C7 | 178.8 (3) | C9—C10—C10i—C9i | 180.0 (3) |
Symmetry codes: (i) −x+1, −y, −z+2; (ii) −x+9/2, y−1/2, −z+3/2; (iii) −x+9/2, y+1/2, −z+3/2. |
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