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In the title compound, C14H28Br2, the mol­ecule is centrosymmetric and the molecular skeleton, including both terminal Br atoms, has an all-trans conformation. In the crystal structure, the mol­ecules form layers in which the long axes of the mol­ecules are inclined with respect to the layers. The molecules are arranged in a zigzag manner in the neighboring layers, making a herring-bone motif just as in the tilt-smectic C phase of liquid crystals.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536803008924/ob6239sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536803008924/ob6239Isup2.hkl
Contains datablock I

CCDC reference: 214636

Key indicators

  • Single-crystal X-ray study
  • T = 296 K
  • Mean [sigma](C-C) = 0.006 Å
  • R factor = 0.043
  • wR factor = 0.099
  • Data-to-parameter ratio = 21.1

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No syntax errors found

ADDSYM reports no extra symmetry








Comment top

Normal long-chain aliphatic compounds such as n-alkanes, a-monosubstituted n-alkanes, and α,ω-disubstituted n-alkanes, have been investigated for disclosing 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, which is one of the typical features of liquid crystalline molecules, and the molecules in the crystalline state form a layered structure similar to those of the smectic liquid crystalline phase. Moreover, some of them exhibit a high-temperature rotator phase just below their melting points in which molecules have motional freedom in some degree as well as that in liquid crystals. Therefore, normal long-chain aliphatic compounds have also been investigated as models for the smectic liquid crystals.

In these investigations, it is important to obtain the detailed crystal data. Up until now, many researchers have studied 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. Michaud et al., 2000), and α,ω-disubstituted n-alkanes such as 1,12-dibromododecane (Kulpe et al., 1981) and 11-bromoundecane-1-ol (Rosen & Hybl, 1972). Recently, we have systematically analyzed the crystal structures of alkane-α,ω-diols containing 10–19 and 21–23 C atoms (Nakamura et al., 2001; Uno et al., 2002), and we have studied the phase-transition phenomena of the series of alkane-α,ω-diols containing 13–24 C atoms (Ogawa & Nakamura, 1999). In addition, we have also analyzed the crystal structures of 1,16-dibromohexadecane (Kobayashi et al., 1995) and 1,18-dibromooctadecane (Nakamura et al., 1993) in order to elucidate the effect of the terminal groups in normal long-chain aliphatic compounds. Against these backgrounds, we have carried out the crystal structure analysis of 1,14-dibromotetradecane, (I). In this paper, the crystal structure of (I) is described and compared with those of the homologous series and the analogous compounds.

The molecular structure of (I) is shown in Fig. 1. The molecule is centrosymmetric and all torsion angles are about ±180°, that is, the molecular skeleton containing both terminal Br atoms has an all-trans conformation. Fig. 2 shows the projection of the crystal structure of (I) along the b axis. The molecules form layers with a thickness of c/2. In the layer, the long axes of the molecules are inclined at 37.9 (1)° with respect to the normal line to the basal plane of Br atoms, the ab plane. This layer structure is similar to those of the triclinic structure of the even-numbered n-alkanes containing 6–24 C atoms, but the inclination angle of (I) is larger than those of the even-numbered n-alkanes [e.g. n-icosane: 18.5 (1)°; Nyburg & Gerson, 1992]. It is considered that the arrangement in the layer is influenced by the steric and electrostatic repulsion of Br atoms at both ends. As the result, a molecular position in the layer is slid along the direction of the long axis of the neighboring molecule.

The repulsion also influences the interlayer arrangement so that the molecules between the neighboring layers swivel on its long axis with the dihedral angle of the trans zigzag planes of 30.1 (2)°. Moreover, the layers are arranged in a zigzag manner between the neighboring layers making a herringbone motif just like the tilt–smectic C phase of liquid crystals, as shown in Fig.3. The layers are stacked closely in such a way that the α-CH2 groups are allowed to fit into the grooves formed by Br atoms with the nearest contacts of 3.758 (3) Å, which agree closely with the van der Waals contacts of 3.75 Å (Rowland & Taylor, 1996). Such a closed packing is observed in the even-numbered alkane-α,ω-diols containing 4–18 and 22 C atoms (e.g. Thalladi et al., 2000), also.

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), 1,16-dibromohexadecane (Kobayashi et al., 1995), and 1,18-dibromooctadecane (Nakamura et al., 1993).

Experimental top

The title compound, (I), was synthesized from commercially available 1,14-tetradecanedioic acid (Tokyo Kasei Kogyo Co. Ltd) by esterification, reduction, and bromination. The pure compound was obtained through fractional distillation and recrystallization. The single-crystal of (I) used for the X-ray analysis was grown by slow evaporation from a solution containing a mixture of n-heptane and 2-propanol (1:3).

Refinement top

All H atoms were located at idealized positions (C—H = 0.95 Å). The H-atom isotropic displacement parameters were set to be 1.2 Ueq of the parent C atom.

Computing details top

Data collection: MSC/AFC Diffractometer Control Software Molecular Structure Corporation, 1992); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: CrystalStructure (Molecular Structure Corporation & 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.

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), showing the crystallographic numbering scheme [symmetry code: (i) 2 − x, −y, −z]. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. The projection of the crystal structure of (I) along the b axis.
[Figure 3] Fig. 3. The projection of the crystal structure of (I) along the a axis.
(I) top
Crystal data top
C14H28Br2F(000) = 364.00
Mr = 356.16Dx = 1.440 Mg m3
Monoclinic, P21/nMelting point: 322.9(4) K
Hall symbol: -P 2ynCu Kα radiation, λ = 1.54178 Å
a = 5.486 (6) ÅCell parameters from 22 reflections
b = 5.389 (7) Åθ = 9.6–19.9°
c = 27.827 (4) ŵ = 6.06 mm1
β = 93.38 (4)°T = 296 K
V = 821.2 (14) Å3Plate, colorless
Z = 20.43 × 0.43 × 0.08 mm
Data collection top
Rigaku AFC-5R
diffractometer
Rint = 0.038
ω scansθmax = 70.1°
Absorption correction: numerical
(NUMABS; Higashi, 1999)
h = 61
Tmin = 0.208, Tmax = 0.782k = 06
2304 measured reflectionsl = 3333
1563 independent reflections1 standard reflections every 150 reflections
1305 reflections with F2 > 2σ(F2) intensity decay: 2.8%
Refinement top
Refinement on F2 w = 1/[0.0002Fo2 + 8.4σ2(Fo) + 0.21]/(4Fo2)
R[F2 > 2σ(F2)] = 0.043(Δ/σ)max < 0.001
wR(F2) = 0.099Δρmax = 0.54 e Å3
S = 1.00Δρmin = 0.55 e Å3
1563 reflectionsExtinction correction: Larson (1970)
74 parametersExtinction coefficient: 24.8 (2)
H-atom parameters not refined
Crystal data top
C14H28Br2V = 821.2 (14) Å3
Mr = 356.16Z = 2
Monoclinic, P21/nCu Kα radiation
a = 5.486 (6) ŵ = 6.06 mm1
b = 5.389 (7) ÅT = 296 K
c = 27.827 (4) Å0.43 × 0.43 × 0.08 mm
β = 93.38 (4)°
Data collection top
Rigaku AFC-5R
diffractometer
1305 reflections with F2 > 2σ(F2)
Absorption correction: numerical
(NUMABS; Higashi, 1999)
Rint = 0.038
Tmin = 0.208, Tmax = 0.7821 standard reflections every 150 reflections
2304 measured reflections intensity decay: 2.8%
1563 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.04374 parameters
wR(F2) = 0.099H-atom parameters not refined
S = 1.00Δρmax = 0.54 e Å3
1563 reflectionsΔρmin = 0.55 e Å3
Special details top

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
xyzUiso*/Ueq
Br10.1134 (1)0.8399 (1)0.21295 (2)0.0779 (2)
C10.0619 (9)0.5449 (9)0.1940 (2)0.072 (1)
C20.2116 (8)0.5888 (9)0.1518 (2)0.066 (1)
C30.3428 (9)0.3564 (8)0.1376 (1)0.066 (1)
C40.4975 (8)0.3954 (8)0.0945 (1)0.065 (1)
C50.6325 (8)0.1670 (8)0.0796 (1)0.063 (1)
C60.7857 (8)0.2070 (8)0.0365 (1)0.065 (1)
C70.9241 (8)0.0196 (9)0.0214 (1)0.064 (1)
H10.16690.49260.22040.0868*
H20.05340.41780.18600.0868*
H30.10750.64270.12540.0788*
H40.32890.71400.15990.0788*
H50.44620.30290.16420.0786*
H60.22480.23160.12970.0786*
H70.39330.44830.06810.0777*
H80.61410.52140.10250.0777*
H90.73740.11450.10600.0759*
H100.51620.04070.07170.0759*
H110.68020.25800.01000.0783*
H120.90060.33480.04430.0783*
H131.02990.07040.04790.0771*
H140.80930.14760.01370.0771*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0904 (5)0.0653 (3)0.0810 (4)0.0090 (3)0.0306 (3)0.0013 (3)
C10.086 (3)0.062 (3)0.072 (3)0.012 (2)0.026 (3)0.005 (2)
C20.071 (3)0.060 (2)0.067 (2)0.002 (2)0.017 (2)0.003 (2)
C30.073 (3)0.064 (3)0.061 (2)0.006 (2)0.019 (2)0.002 (2)
C40.072 (3)0.063 (3)0.062 (2)0.004 (2)0.018 (2)0.003 (2)
C50.071 (3)0.064 (3)0.056 (2)0.006 (2)0.016 (2)0.001 (2)
C60.073 (3)0.065 (3)0.058 (2)0.005 (2)0.018 (2)0.002 (2)
C70.070 (3)0.065 (3)0.059 (2)0.007 (2)0.016 (2)0.002 (2)
Geometric parameters (Å, º) top
Br1—C11.947 (5)C2—H40.95
C1—C21.490 (5)C3—H50.95
C2—C31.509 (6)C3—H60.95
C3—C41.523 (5)C4—H70.95
C4—C51.507 (6)C4—H80.95
C5—C61.520 (5)C5—H90.95
C6—C71.510 (6)C5—H100.95
C7—C7i1.508 (7)C6—H110.95
C1—H10.95C6—H120.95
C1—H20.95C7—H130.95
C2—H30.95C7—H140.95
Br1···Br1ii3.758 (3)Br1···Br1iii3.758 (3)
Br1—C1—C2112.8 (3)H5—C3—H6109.5
C1—C2—C3111.6 (4)C3—C4—H7108.3
C2—C3—C4112.9 (4)C5—C4—H7108.3
C3—C4—C5114.2 (4)C3—C4—H8108.3
C4—C5—C6114.0 (4)C5—C4—H8108.3
C5—C6—C7114.5 (4)H7—C4—H8109.5
C6—C7—C7i114.6 (5)C4—C5—H9108.3
Br1—C1—H1108.6C6—C5—H9108.3
C2—C1—H1108.6C4—C5—H10108.3
Br1—C1—H2108.6C6—C5—H10108.3
C2—C1—H2108.6H9—C5—H10109.5
H1—C1—H2109.5C5—C6—H11108.2
C1—C2—H3108.9C7—C6—H11108.2
C3—C2—H3108.9C5—C6—H12108.2
C1—C2—H4108.9C7—C6—H12108.2
C3—C2—H4108.9H11—C6—H12109.5
H3—C2—H4109.5C6—C7—H13108.2
C2—C3—H5108.6C7i—C7—H13108.2
C4—C3—H5108.6C6—C7—H14108.2
C2—C3—H6108.6C7i—C7—H14108.2
C4—C3—H6108.6H13—C7—H14109.5
Br1—C1—C2—C3179.3 (3)C4—C5—C6—C7179.4 (4)
C1—C2—C3—C4180.0 (4)C5—C6—C7—C7i179.8 (5)
C2—C3—C4—C5179.6 (4)C6—C7—C7i—C6i180.0
C3—C4—C5—C6179.8 (4)
Symmetry codes: (i) x+2, y, z; (ii) x1/2, y1/2, z+1/2; (iii) x1/2, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC14H28Br2
Mr356.16
Crystal system, space groupMonoclinic, P21/n
Temperature (K)296
a, b, c (Å)5.486 (6), 5.389 (7), 27.827 (4)
β (°) 93.38 (4)
V3)821.2 (14)
Z2
Radiation typeCu Kα
µ (mm1)6.06
Crystal size (mm)0.43 × 0.43 × 0.08
Data collection
DiffractometerRigaku AFC-5R
diffractometer
Absorption correctionNumerical
(NUMABS; Higashi, 1999)
Tmin, Tmax0.208, 0.782
No. of measured, independent and
observed [F2 > 2σ(F2)] reflections
2304, 1563, 1305
Rint0.038
(sin θ/λ)max1)0.610
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.043, 0.099, 1.00
No. of reflections1563
No. of parameters74
No. of restraints?
H-atom treatmentH-atom parameters not refined
Δρmax, Δρmin (e Å3)0.54, 0.55

Computer programs: MSC/AFC Diffractometer Control Software Molecular Structure Corporation, 1992), MSC/AFC Diffractometer Control Software, CrystalStructure (Molecular Structure Corporation & Rigaku, 2001), SIR92 (Altomare et al., 1994), CRYSTALS (Watkin et al., 1996), ORTEP-3 for Windows (Farrugia, 1997), CrystalStructure.

Selected geometric parameters (Å, º) top
Br1—C11.947 (5)C4—C51.507 (6)
C1—C21.490 (5)C5—C61.520 (5)
C2—C31.509 (6)C6—C71.510 (6)
C3—C41.523 (5)C7—C7i1.508 (7)
Br1···Br1ii3.758 (3)Br1···Br1iii3.758 (3)
Br1—C1—C2—C3179.3 (3)C4—C5—C6—C7179.4 (4)
C1—C2—C3—C4180.0 (4)C5—C6—C7—C7i179.8 (5)
C2—C3—C4—C5179.6 (4)C6—C7—C7i—C6i180.0
C3—C4—C5—C6179.8 (4)
Symmetry codes: (i) x+2, y, z; (ii) x1/2, y1/2, z+1/2; (iii) x1/2, y+1/2, z+1/2.
 

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