1,20 Dibromoicosane

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Nakamura and Ohishi C₂₀H₄₀Br₂ DOI: 10.1107/S1600536804017556 Acta Cryst.(2004). E60, o1408±o1410 Acta Crystallographica Section E

Structure Reports Online

ISSN 1600-5368

1,20-Dibromoicosane

Naotake Nakamura* and Akira Ohishi

Department of Applied Chemistry, College of Science and Engineering, Ritsumeikan Univer-sity, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan

Correspondence e-mail: [email protected]

Key indicators Single-crystal X-ray study

T= 296 K

Mean(C±C) = 0.005 AÊ

Rfactor = 0.038

wRfactor = 0.116

Data-to-parameter ratio = 16.6

For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.

The molecule of the title compound, C20H40Br2, is

centrosym-metric 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 CAphase of liquid crystals.

Comment

Normal long-chain aliphatic compounds, for example

n-alkanes, have been studied to elucidate the principles of

organic chemical crystallography and basic polymer science,

because the molecular skeleton consists of a simple trans

zigzag straight hydrocarbon chain. The molecular shape of these compounds can be regarded as rod-like, and the mol-ecules in the crystalline state form a layered structure similar to those of the smectic liquid crystalline phase. Moreover, some of these compounds exhibit a high-temperature rotator phase just below their melting points, in which molecules have motional freedom to some degree as well as that in liquid crystals. As a result, normal long-chain aliphatic compounds have also been investigated as models for smectic liquid crystals.

In these investigations, it is important to obtain detailed crystallographic data. Many researchers have analyzed the crystal structures of many different kinds of normal long-chain

aliphatic compounds, for example, n-alkanes (e.g. Nyburg &

Gerson, 1992),n-primary alcohols (e.g.Michaudet al., 2000),

and ,!-disubstituted n-alkanes, such as

1,12-dibromodo-decane (Kulpeet al., 1981) and 11-bromoundecan-1-ol (Rosen

& Hybl, 1972). Recently, we have systematically analysed the crystal structures of the alkane-,!-diols containing 10±19 and

21±23 C atoms (Nakamuraet al., 2001; Unoet al., 2002), and

we have studied the phase-transition phenomena of the series

of the alkane-,!-diols containing 13±24 C atoms (Ogawa &

Nakamura, 1999). In the present paper, we report the crystal structure analysis of the title compound, (I), in order to elucidate the effect of the terminal groups in normal long-chain aliphatic compounds.

The molecular structure of (I) is shown in Fig. 1. The mol-ecule is centrosymmetric and all torsion angles are close to

180_{, that is, the molecular skeleton including both terminal}

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Br atoms has an all-trans conformation. Fig. 2 shows the

projection of the crystal structure of (I) along thebaxis. The

molecules form layers with a thickness ofc/2. In the layer, the

long axes of the molecules are inclined to theabplane. This

layer structure is similar to that of the triclinic structure of the

even-numbered n-alkanes containing 6±24 C atoms. It is

considered that the arrangement in the layer is in¯uenced by the steric and electrostatic repulsion of Br atoms at both ends. As a result, a molecular position in the layer slides along the direction of the long axis of the neighboring molecule.

Moreover, the layers are arranged in a zigzag manner between the neighboring layers, forming a herringbone motif

similar to the tilt-smectic C phase and the smectic CAphase of

liquid crystals, as shown in Fig. 3. The layers are stacked

closely in such a way that the-CH2groups are allowed to ®t

into the grooves formed by Br atoms, with nearest contacts of 3.752 (3) AÊ, agreeing closely with the van der Waals contacts of 3.75 AÊ (Rowland & Taylor, 1996). Such a close packing is

observed in the even-numbered alkane-,!-diols containing

4±19 and 21±23 C atoms (e.g.Thalladiet al., 2000) and the,! -dichloroalkanes containing 16, 20 and 26 C atoms (Takami-zawaet al., 1992).

organic papers

Acta Cryst.(2004). E60, o1408±o1410 Nakamura and Ohishi C₂₀H₄₀Br₂

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Figure 1

The molecular structure of (I), showing the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry code: (i) 2ÿx,ÿy,ÿz.]

Figure 2

The projection of the crystal structure of (I) along thebaxis.

Figure 3

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The features in the molecular and crystal structure of (I) are similar to those of the homologous series with an even number

of C atoms, viz. 1,12-dibromododecane (Kulpe et al., 1981),

1,14-dibromotetradecane (Uno & Nakamura, 2003),

1,16-di-bromohexadecane (Kobayashi et al., 1995),

1,18-dibromo-octadecane (Nakamura et al., 1993), and

1,26-dibromohexadecane (Takamizawaet al., 1992).

Experimental

Thin plate-like crystals of (I) were grown by slow evaporation of a solution containing a mixture ofn-hexane and ethanol (1:1). The well developed face of the crystal is (001).

Crystal data C20H40Br2

Mr= 440.34

Monoclinic,P21=n

a= 5.482 (4) AÊ

b= 5.383 (2) AÊ

c= 37.412 (2) AÊ

= 91.50 (2)

V= 1103.6 (9) AÊ3

Z= 2

Dx= 1.325 Mg mÿ3

CuKradiation Cell parameters from 24

re¯ections

= 9.5±15.5

= 4.61 mmÿ1

T= 296 (1) K Plate, colorless 0.590.470.04 mm Data collection

Rigaku AFC-5Rdiffractometer

!±2scans

Absorption correction: by integration (NUMABS; Higashi, 1999)

Tmin= 0.325,Tmax= 0.997

3004 measured re¯ections 2008 independent re¯ections 1667 re¯ections withF2_{> 2}₍_F2₎

Rint= 0.028

max= 70.1

h=ÿ1!6

k= 0!6

l=ÿ45!45 3 standard re¯ections

every 150 re¯ections intensity decay: 6.8%

Re®nement Re®nement onF2

R[F2_{> 2}₍_F2_{)] = 0.038}

wR(F2_{) = 0.116}

S= 1.00 2008 re¯ections 121 parameters

H-atom parameters constrained

w= (4Fo2)/[0.001Fo2+ 5.32(Fo) +

0.52] (/)max< 0.001

max= 0.38 e AÊÿ3

min=ÿ0.62 e AÊÿ3

Extinction correction: (Larson, 1970)

Extinction coef®cient: 21.3 (3)

Table 1

Selected geometric parameters (AÊ,_).

Br1ÐC1 1.946 (4) C1ÐC2 1.489 (5) C2ÐC3 1.514 (5) C3ÐC4 1.526 (5) C4ÐC5 1.514 (5) C5ÐC6 1.522 (4)

C6ÐC7 1.510 (5) C7ÐC8 1.514 (4) C8ÐC9 1.509 (5) C9ÐC10 1.518 (4) C10ÐC10ii _{1.507 (5)}

Br1ÐC1ÐC2ÐC3 ÿ179.6 (2) C1ÐC2ÐC3ÐC4 179.4 (3) C2ÐC3ÐC4ÐC5 179.7 (3) C3ÐC4ÐC5ÐC6 ÿ179.7 (3) C4ÐC5ÐC6ÐC7 178.8 (3)

C5ÐC6ÐC7ÐC8 179.2 (3) C6ÐC7ÐC8ÐC9 179.8 (3) C7ÐC8ÐC9ÐC10 ÿ179.8 (3) C8ÐC9ÐC10ÐC10ii _{179.7 (3)}

C9ÐC10ÐC10ii_ÐC9ii _{180.0 (3)}

Symmetry code: (ii) 1ÿx;ÿy;2ÿz.

Table 2

Intermolecular contacts (AÊ).

Br1 Br1iii _{3.752 (3)} _Br1_Br1iv _{3.752 (3)}

Symmetry codes: (iii)9

2ÿx;yÿ12;32ÿz; (iv)92ÿx;12y;32ÿz.

H atoms were positioned geometrically and treated as riding, with CÐH distances of 0.95 AÊ andUiso(H) = 1.2Ueq(parent).

Data collection: MSC/AFC Diffractometer Control Software

(Molecular Structure Coorporation, 1992); cell re®nement: MSC/

AFC Diffractometer Control Software; data reduction: Crystal-Structure (Molecular Structure Coorporation & Rigaku, 2001); program(s) used to solve structure:SIR92 (Altomare et al., 1994); program(s) used to re®ne structure:CRYSTALS(Watkinet al., 1996); molecular graphics:ORTEP-3 for Windows(Farrugia, 1997); soft-ware used to prepare material for publication:CrystalStructure.

The authors express their gratitude to Mr K. Uno and Mr H. Shimizu for their support.

References

Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994).J. Appl. Cryst.27, 435.

Farrugia, L. J. (1997).J. Appl. Cryst.30, 565.

Higashi, T. (1999).NUMABS.Rigaku Corporation, Tokyo, Japan.

Kobayashi, H., Yamamoto, T. & Nakamura, N. (1995).Cryst. Res. Technol.30, 275±280.

Kulpe, S., Seidel, I., Szulzewsky, K., Steger, U. & Steger, E. (1981).Cryst. Res. Technol.16, 349±356.

Larson, A. C. (1970).Crystallographic Computing, edited by F. R. Ahmed, S. R. Hall & C. P. Huber, pp. 291±294. Copenhagen: Munksgaard. Michaud, F., VentolaÁ, L., Calvet, M. T., Cuevas-Diarte, M. A., Solans, X. &

Font-BardõÂa, M. (2000).Acta Cryst.C56, 219±221.

Molecular Structure Corporation (1992).MSC/AFC Diffractometer Control Software. MSC, 3200 Research Forest Drive, The Woodlands, TX 77381, USA.

Molecular Structure Corporation & Rigaku (2001).CrystalStructure.Version 3.10. MSC, 9009 New Trails Drive, The Woodlands, TX 77381-5209, USA, and Rigaku Corporation, 3-9-12 Akishima, Tokyo 196-8666, Japan. Nakamura, N., Uno, K. & Ogawa, Y. (2001). Acta Cryst. E57, o1091±

o1093.

Nakamura, N., Yamamoto, T., Kobayashi, H. & Yoshimura, Y. (1993).Cryst. Res. Technol.28, 953±957.

Nyburg, S. C. & Gerson, A. R. (1992).Acta Cryst.B48, 103±106. Ogawa, Y. & Nakamura, N. (1999).Bull. Chem. Soc. Jpn,72, 943±946. Rosen, L. S. & Hybl, A. (1972).Acta Cryst.B28, 610±617.

Rowland, R. S. & Taylor, R. (1996).J. Phys. Chem.100, 7384±7391. Takamizawa, K., Kodama, M., Matsunaga, S. & Shiokawa, K. (1992).Eng. Sci.

Rep. Kyushu Univ.13, 341±347.

Thalladi, V. R., Boese, R. & Weiss, H. C. (2000).Angew. Chem. Int. Ed.39, 918±922.

Uno, K. & Nakamura, N. (2003).Acta Cryst.E59, o708±o710.

Uno, K., Nakamura, N. & Ogawa, Y. (2002). Acta Cryst. A58 (Suppl.), C-338.

Watkin, D. J., Prout, C. K., Carruthers, J. R. & Betteridge, P. W. (1996).

CRYSTALS.Issue 10. Chemical Crystallography Laboratory, University of Oxford, England.

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sup-1 Acta Cryst. (2004). E60, o1408–o1410

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Acta Cryst. (2004). E60, o1408–o1410 [https://doi.org/10.1107/S1600536804017556]

1,20-Dibromoicosane

Naotake Nakamura and Akira Ohishi

(I)

Crystal data C20H40Br2 Mr = 440.34

Monoclinic, P21/n Hall symbol: -P 2yn a = 5.482 (4) Å b = 5.383 (2) Å c = 37.412 (2) Å β = 91.50 (2)° V = 1103.6 (9) Å3 Z = 2

F(000) = 460.00 Dx = 1.325 Mg m−3

Cu Kα radiation, λ = 1.5418 Å Cell parameters from 24 reflections θ = 9.5–15.5°

µ = 4.61 mm−1 T = 296 K Plate, colorless 0.59 × 0.47 × 0.04 mm

Data collection Rigaku AFC-5R

diffractometer ω–2θ scans

Absorption correction: integration (NUMABS; Higashi, 1997) Tmin = 0.325, Tmax = 0.997 3004 measured reflections 2008 independent reflections

1667 reflections with F2_{> 2}_σ₍_F2₎ Rint = 0.028

θmax = 70.1° h = −1→6 k = 0→6 l = −45→45

3 standard reflections every 150 reflections intensity decay: 6.8%

Refinement Refinement on F2 R[F2_{> 2}_σ₍_F2_{)] = 0.038} wR(F2_{) = 0.116} S = 1.00 2008 reflections 121 parameters

H-atom parameters constrained

w = 1/[0.001Fo2 + 5.3σ2(Fo) + 0.52]/(4Fo2) (Δ/σ)max < 0.001

Δρmax = 0.38 e Å−3 Δρmin = −0.62 e Å−3

Extinction correction: (Larson, 1970) Extinction coefficient: 21.3 (3)

Special details

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₎

x y z Uiso*/Ueq

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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₎

U11 _U22 _U33 _U12 _U13 _U23

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Geometric parameters (Å, º)

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)}

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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)}

1,20 Di­bromo­i­cosane

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1,20-Dibromoicosane

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1,20-Dibromoicosane

Naotake Nakamura and Akira Ohishi

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1,20 Dibromoicosane