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In the centrosymmetric title compound, C18H28Br2O2, the alkyl chains adopt a fully extended all-trans conformation and each of them is almost planar. In addition, the alkyl chains are coplanar with the benzene ring. Inter­molecular Br...Br inter­actions [3.410 (3) Å] are present, resulting in a one-dimensional supra­molecular architecture.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536808028730/si2104sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536808028730/si2104Isup2.hkl
Contains datablock I

CCDC reference: 706063

Key indicators

  • Single-crystal X-ray study
  • T = 295 K
  • Mean [sigma](C-C) = 0.004 Å
  • R factor = 0.026
  • wR factor = 0.064
  • Data-to-parameter ratio = 18.0

checkCIF/PLATON results

No syntax errors found



Alert level C ABSTM02_ALERT_3_C The ratio of expected to reported Tmax/Tmin(RR) is > 1.10 Tmin and Tmax reported: 0.391 0.764 Tmin and Tmax expected: 0.331 0.750 RR = 1.159 Please check that your absorption correction is appropriate. PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor .... 2.06 PLAT431_ALERT_2_C Short Inter HL..A Contact Br1 .. Br1 .. 3.41 Ang. PLAT060_ALERT_4_C Ratio Tmax/Tmin (Exp-to-Rep) (too) Large ....... 1.17 PLAT062_ALERT_4_C Rescale T(min) & T(max) by ..................... 0.98 PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given ....... ? PLAT154_ALERT_1_C The su's on the Cell Angles are Equal (x 10000) 200 Deg.
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 7 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 1 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 3 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Comment top

Noncovalent interactions play an important role in designing superstructures (Brammer, 2004). Among these weak forces, the intermolecular interactions between halogen atoms have been a subject of interest (Desiraju et al., 1989). In order to gain more insight into the structure-regulating ability of intermolecular Br···Br interactions, herein we report the crystal structure of the title compound.

A view of the centrosymmetric molecular structure of the title compound is given in Fig.1. The alkyl chains are in the fully extended all-trans conformation and each of them is almost perfectly planar. The C—C—O—C torsion angles of 3.4 (4)o, indicate that the two alkyl chains are coplanar with the benzene ring. The crystal structure of the titile compound reveals the presence of a near linear C—Br···Br fragment[C—Br···Br=155.6 (3)o], the Br···Br distance (3.410 Å) is shorter than the sum of van der Waals radii(3.72 Å) and those in the other compound [3.634 (4)–3.9527 (9) Å](Kuriger et al., 2008; Ali et al., 2008). Owing to the intermolecular Br···Br interactions, the crystal structure of the title compound is extended to a one-dimensional chain structure. The chains are intercalated by van der Waals forces (Fig.2).

Related literature top

For related literature, see: Ali et al. (2008); Brammer (2004); Desiraju & Parthasarathy (1989); Kuriger et al. (2008); Maruyama & Kawanishi (2002).

Experimental top

The title compound was prepared as described in literature (Maruyama & Kawanishi 2002) and recrystallized from dichloromethane-ethanol at room temperature to give the desired crystals suitable for single-crystal X-ray diffraction.

Refinement top

H atoms attached to C atoms of the title compound were placed in geometrically idealized positions and treated as riding with C—H distances constrained to 0.93 (aromatic CH), or 0.96 Å (methyl CH3), and 0.97 Å (methylene CH2) and constrained to ride on their parent atoms, with Uĩso~(H) = 1.2Ueq(C)(1.5Ueq for methyl H).

Computing details top

Data collection: SMART (Bruker, 2004); cell refinement: SMART (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with displacement ellipsoids at the 50% probability level. Inversion related atoms are labelled with an A. (Symmetry code: -x, 1 - y, -z).
[Figure 2] Fig. 2. Partial view of the crystal packing showing the formation of the infinite chains of molecules formed by the intermolecular Br···Br interactions. Intercalated neighboring chains complete the sheets in the structure running parallel to (100). H atoms have been omitted for clarity.
1,4-Dibromo-2,5-bis(hexyloxy)benzene top
Crystal data top
C18H28Br2O2Z = 1
Mr = 436.22F(000) = 222
Triclinic, P1Dx = 1.469 Mg m3
a = 6.9638 (12) ÅMo Kα radiation, λ = 0.71073 Å
b = 8.2581 (14) ÅCell parameters from 1772 reflections
c = 9.7321 (17) Åθ = 2.3–26.0°
α = 107.012 (2)°µ = 4.12 mm1
β = 106.981 (2)°T = 295 K
γ = 99.193 (2)°Block, colourless
V = 493.11 (15) Å30.28 × 0.27 × 0.07 mm
Data collection top
Bruker SMART CCD
diffractometer
1818 independent reflections
Radiation source: fine-focus sealed tube1567 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.018
phi and ω scansθmax = 25.5°, θmin = 2.7°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 88
Tmin = 0.391, Tmax = 0.764k = 99
3675 measured reflectionsl = 1111
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.025Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.063H-atom parameters constrained
S = 1.06 w = 1/[σ2(Fo2) + (0.0346P)2 + 0.0096P]
where P = (Fo2 + 2Fc2)/3
1818 reflections(Δ/σ)max = 0.001
101 parametersΔρmax = 0.31 e Å3
0 restraintsΔρmin = 0.23 e Å3
Crystal data top
C18H28Br2O2γ = 99.193 (2)°
Mr = 436.22V = 493.11 (15) Å3
Triclinic, P1Z = 1
a = 6.9638 (12) ÅMo Kα radiation
b = 8.2581 (14) ŵ = 4.12 mm1
c = 9.7321 (17) ÅT = 295 K
α = 107.012 (2)°0.28 × 0.27 × 0.07 mm
β = 106.981 (2)°
Data collection top
Bruker SMART CCD
diffractometer
1818 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
1567 reflections with I > 2σ(I)
Tmin = 0.391, Tmax = 0.764Rint = 0.018
3675 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0250 restraints
wR(F2) = 0.063H-atom parameters constrained
S = 1.06Δρmax = 0.31 e Å3
1818 reflectionsΔρmin = 0.23 e Å3
101 parameters
Special details top

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
xyzUiso*/Ueq
Br10.07253 (4)0.51292 (4)0.31314 (3)0.05768 (13)
O10.3731 (2)0.6878 (2)0.00755 (19)0.0577 (5)
C10.1596 (3)0.4127 (3)0.1410 (3)0.0455 (6)
H10.26560.35490.23660.055*
C20.0292 (3)0.5069 (3)0.1316 (3)0.0418 (5)
C30.1932 (3)0.5970 (3)0.0107 (3)0.0426 (5)
C40.5450 (3)0.7726 (4)0.1511 (3)0.0513 (6)
H4A0.58710.68640.19440.062*
H4B0.50560.85600.22400.062*
C50.7229 (3)0.8672 (3)0.1183 (3)0.0528 (6)
H5A0.67750.95040.07220.063*
H5B0.76100.78240.04550.063*
C60.9133 (3)0.9647 (3)0.2665 (3)0.0539 (6)
H6A0.87551.05160.33770.065*
H6B0.95470.88170.31430.065*
C71.0979 (3)1.0563 (3)0.2370 (3)0.0518 (6)
H7A1.13510.96930.16530.062*
H7B1.05641.13940.18940.062*
C81.2870 (4)1.1524 (4)0.3828 (3)0.0662 (8)
H8A1.33551.06790.42590.079*
H8B1.24711.23260.45760.079*
C91.4646 (4)1.2556 (5)0.3548 (4)0.0850 (10)
H9A1.50321.17710.27950.127*
H9B1.58241.31050.44940.127*
H9C1.42001.34420.31790.127*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.05214 (17)0.0815 (2)0.03895 (16)0.00640 (13)0.01726 (12)0.02627 (13)
O10.0382 (9)0.0797 (12)0.0427 (9)0.0082 (8)0.0094 (7)0.0224 (9)
C10.0369 (12)0.0546 (14)0.0350 (12)0.0026 (10)0.0057 (9)0.0142 (11)
C20.0414 (12)0.0529 (14)0.0330 (11)0.0089 (10)0.0135 (10)0.0199 (10)
C30.0354 (11)0.0501 (13)0.0392 (12)0.0049 (10)0.0115 (10)0.0168 (11)
C40.0368 (12)0.0633 (16)0.0417 (13)0.0004 (11)0.0082 (10)0.0151 (12)
C50.0383 (12)0.0654 (16)0.0481 (14)0.0015 (11)0.0139 (11)0.0193 (12)
C60.0399 (13)0.0629 (17)0.0504 (14)0.0023 (12)0.0136 (11)0.0172 (13)
C70.0404 (13)0.0562 (15)0.0535 (15)0.0043 (11)0.0175 (11)0.0160 (12)
C80.0437 (14)0.0786 (19)0.0592 (17)0.0001 (13)0.0128 (13)0.0150 (15)
C90.0468 (16)0.095 (2)0.086 (2)0.0123 (15)0.0179 (16)0.0156 (19)
Geometric parameters (Å, º) top
Br1—C21.891 (2)C5—H5B0.9700
O1—C31.367 (2)C6—C71.529 (3)
O1—C41.435 (3)C6—H6A0.9700
C1—C3i1.377 (3)C6—H6B0.9700
C1—C21.379 (3)C7—C81.514 (3)
C1—H10.9300C7—H7A0.9700
C2—C31.406 (3)C7—H7B0.9700
C3—C1i1.377 (3)C8—C91.525 (4)
C4—C51.522 (3)C8—H8A0.9700
C4—H4A0.9700C8—H8B0.9700
C4—H4B0.9700C9—H9A0.9600
C5—C61.533 (3)C9—H9B0.9600
C5—H5A0.9700C9—H9C0.9600
C3—O1—C4117.26 (18)C7—C6—H6A109.1
C3i—C1—C2120.9 (2)C5—C6—H6A109.1
C3i—C1—H1119.6C7—C6—H6B109.1
C2—C1—H1119.6C5—C6—H6B109.1
C1—C2—C3121.5 (2)H6A—C6—H6B107.9
C1—C2—Br1119.81 (16)C8—C7—C6112.7 (2)
C3—C2—Br1118.73 (16)C8—C7—H7A109.1
O1—C3—C1i125.49 (19)C6—C7—H7A109.1
O1—C3—C2116.8 (2)C8—C7—H7B109.1
C1i—C3—C2117.70 (19)C6—C7—H7B109.1
O1—C4—C5107.30 (19)H7A—C7—H7B107.8
O1—C4—H4A110.3C7—C8—C9112.5 (3)
C5—C4—H4A110.3C7—C8—H8A109.1
O1—C4—H4B110.3C9—C8—H8A109.1
C5—C4—H4B110.3C7—C8—H8B109.1
H4A—C4—H4B108.5C9—C8—H8B109.1
C4—C5—C6111.0 (2)H8A—C8—H8B107.8
C4—C5—H5A109.4C8—C9—H9A109.5
C6—C5—H5A109.4C8—C9—H9B109.5
C4—C5—H5B109.4H9A—C9—H9B109.5
C6—C5—H5B109.4C8—C9—H9C109.5
H5A—C5—H5B108.0H9A—C9—H9C109.5
C7—C6—C5112.4 (2)H9B—C9—H9C109.5
C3i—C1—C2—C30.4 (4)Br1—C2—C3—C1i178.52 (18)
C3i—C1—C2—Br1178.49 (18)C3—O1—C4—C5178.7 (2)
C4—O1—C3—C1i3.4 (4)O1—C4—C5—C6179.1 (2)
C4—O1—C3—C2176.9 (2)C4—C5—C6—C7178.1 (2)
C1—C2—C3—O1179.4 (2)C5—C6—C7—C8179.8 (2)
Br1—C2—C3—O11.7 (3)C6—C7—C8—C9175.4 (2)
C1—C2—C3—C1i0.4 (4)
Symmetry code: (i) x, y+1, z.

Experimental details

Crystal data
Chemical formulaC18H28Br2O2
Mr436.22
Crystal system, space groupTriclinic, P1
Temperature (K)295
a, b, c (Å)6.9638 (12), 8.2581 (14), 9.7321 (17)
α, β, γ (°)107.012 (2), 106.981 (2), 99.193 (2)
V3)493.11 (15)
Z1
Radiation typeMo Kα
µ (mm1)4.12
Crystal size (mm)0.28 × 0.27 × 0.07
Data collection
DiffractometerBruker SMART CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.391, 0.764
No. of measured, independent and
observed [I > 2σ(I)] reflections
3675, 1818, 1567
Rint0.018
(sin θ/λ)max1)0.606
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.025, 0.063, 1.06
No. of reflections1818
No. of parameters101
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.31, 0.23

Computer programs: SMART (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

 

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