organic compounds
1,4-Dibromo-2,5-dibutoxybenzene
aSchool of Chemical Sciences & Food Technology, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia, bInstitute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia, UKM 43500 Bangi, Selangor, Malaysia, cDepartment of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia, and dFuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 Selangor, Malaysia
*Correspondence e-mail: mbkassim@ukm.my
The 14H20Br2O2, contains one half-molecule located on an inversion centre. The molecule is essentially planar, with a maximum deviation from the best plane of the non-H atoms of 0.054 (2) Å for the O atoms. The butoxy group adopts a fully extended all-trans conformation. In the crystal, molecules are connected via C—Br⋯O halogen bonds [Br⋯O = 3.2393 (19) Å] into a two-dimensional corrugated network in the bc plane.
of the title compound, CRelated literature
For related structures, see: Choi et al. (2010); Fun et al. (2010); Li et al. (2008). For applications of dialkoxybenzenes, see: Brandon et al. (1997); Huang et al. (2007); Lightowler & Hird (2005); Promarak & Ruchirawat (2007). For the synthetic procedure, see: Lopez-Alvarado et al. (2002).
Experimental
Crystal data
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Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2006); 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, PLATON (Spek, 2009) and publCIF (Westrip, 2010).
Supporting information
10.1107/S1600536812033338/gk2508sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812033338/gk2508Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812033338/gk2508Isup3.cml
The compound was prepared according to previously published work with a slight modification (Lopez-Alvarado et al., 2002). To 1,4-bis(butoxy)benzene (5.00 g, 22.5 mmol) was added dropwise Br2 (7. 55 g, 47.25 mmol) in glacial acetic acid. The mixture was stirred at room temperature for two hours followed by heating under reflux for another two hours. The mixture was left to cool to room temperature and water was then added to precipitate the product. The product was filtered, washed with excess water and 1.0 M sodium bicarbonate solution. Slow recrystallization of the product from methanol–ethyl acetate mixture afforded crystals suitable for single X-ray diffraction (yield: 82%).
The hydrogen atom positions were calculated geometrically and refined in a riding model approximation with C–H bond lengths in the range 0.93–0.97 Å and Uiso(H) = 1.2Ueq(C) for aromatic and CH2 group, and Uiso(H) = 1.5Ueq(C) for methyl group.
Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell
CrysAlis CCD (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); 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), PLATON (Spek, 2009) and publCIF (Westrip, 2010).C14H20Br2O2 | F(000) = 380 |
Mr = 380.10 | Dx = 1.690 Mg m−3 |
Monoclinic, P21/c | Melting point = 343–345 K |
Hall symbol: -P 2ybc | Cu Kα radiation, λ = 1.54178 Å |
a = 8.3685 (4) Å | Cell parameters from 2679 reflections |
b = 12.6395 (5) Å | θ = 3–71° |
c = 7.1083 (3) Å | µ = 6.82 mm−1 |
β = 96.461 (5)° | T = 150 K |
V = 747.10 (6) Å3 | Plate, colourless |
Z = 2 | 0.07 × 0.06 × 0.01 mm |
Oxford Diffraction Gemini diffractometer | 1442 independent reflections |
Radiation source: fine-focus sealed tube | 1303 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.029 |
ω scans | θmax = 71.6°, θmin = 5.3° |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2006) | h = −8→10 |
Tmin = 0.647, Tmax = 0.935 | k = −15→15 |
5426 measured reflections | l = −8→6 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.030 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.081 | H-atom parameters constrained |
S = 1.07 | w = 1/[σ2(Fo2) + (0.0507P)2 + 0.4756P] where P = (Fo2 + 2Fc2)/3 |
1442 reflections | (Δ/σ)max < 0.001 |
83 parameters | Δρmax = 0.73 e Å−3 |
0 restraints | Δρmin = −0.38 e Å−3 |
C14H20Br2O2 | V = 747.10 (6) Å3 |
Mr = 380.10 | Z = 2 |
Monoclinic, P21/c | Cu Kα radiation |
a = 8.3685 (4) Å | µ = 6.82 mm−1 |
b = 12.6395 (5) Å | T = 150 K |
c = 7.1083 (3) Å | 0.07 × 0.06 × 0.01 mm |
β = 96.461 (5)° |
Oxford Diffraction Gemini diffractometer | 1442 independent reflections |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2006) | 1303 reflections with I > 2σ(I) |
Tmin = 0.647, Tmax = 0.935 | Rint = 0.029 |
5426 measured reflections |
R[F2 > 2σ(F2)] = 0.030 | 0 restraints |
wR(F2) = 0.081 | H-atom parameters constrained |
S = 1.07 | Δρmax = 0.73 e Å−3 |
1442 reflections | Δρmin = −0.38 e Å−3 |
83 parameters |
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems open-flow nitrogen cryostat (Cosier & Glazer 1986) with a nominal stability of 0.1 K. Cosier, J. & Glazer, A.M., (1986)., J. Appl. Cryst. 105 107. |
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. |
x | y | z | Uiso*/Ueq | ||
Br1 | −0.15758 (3) | 1.17923 (2) | 0.20385 (4) | 0.01819 (14) | |
O1 | 0.2931 (2) | 0.90585 (15) | 0.4561 (3) | 0.0186 (4) | |
C1 | −0.0674 (3) | 1.0747 (2) | 0.3762 (4) | 0.0165 (6) | |
C2 | 0.0787 (3) | 1.0299 (2) | 0.3466 (4) | 0.0170 (6) | |
H2 | 0.1301 | 1.0506 | 0.2431 | 0.020* | |
C3 | 0.1490 (3) | 0.9538 (2) | 0.4722 (4) | 0.0160 (5) | |
C4 | 0.3733 (4) | 0.9319 (2) | 0.2931 (4) | 0.0188 (6) | |
H4A | 0.4017 | 1.0064 | 0.2949 | 0.023* | |
H4B | 0.3034 | 0.9175 | 0.1776 | 0.023* | |
C5 | 0.5229 (3) | 0.8644 (2) | 0.3018 (4) | 0.0199 (6) | |
H5A | 0.4923 | 0.7904 | 0.2966 | 0.024* | |
H5B | 0.5883 | 0.8766 | 0.4213 | 0.024* | |
C6 | 0.6222 (3) | 0.8887 (2) | 0.1394 (4) | 0.0202 (6) | |
H6A | 0.5590 | 0.8727 | 0.0198 | 0.024* | |
H6B | 0.6483 | 0.9635 | 0.1403 | 0.024* | |
C7 | 0.7771 (4) | 0.8243 (2) | 0.1556 (5) | 0.0249 (7) | |
H7A | 0.8411 | 0.8413 | 0.2724 | 0.037* | |
H7B | 0.8363 | 0.8409 | 0.0513 | 0.037* | |
H7C | 0.7516 | 0.7503 | 0.1535 | 0.037* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.0183 (2) | 0.01468 (19) | 0.0219 (2) | 0.00149 (10) | 0.00335 (13) | 0.00358 (10) |
O1 | 0.0161 (10) | 0.0183 (9) | 0.0223 (10) | 0.0030 (8) | 0.0061 (8) | 0.0029 (8) |
C1 | 0.0200 (15) | 0.0114 (12) | 0.0174 (13) | 0.0022 (10) | −0.0003 (10) | 0.0031 (10) |
C2 | 0.0185 (14) | 0.0134 (12) | 0.0200 (14) | −0.0002 (10) | 0.0063 (11) | 0.0002 (10) |
C3 | 0.0149 (13) | 0.0127 (12) | 0.0202 (14) | 0.0005 (10) | 0.0012 (10) | −0.0017 (10) |
C4 | 0.0209 (15) | 0.0175 (13) | 0.0188 (14) | −0.0002 (11) | 0.0062 (11) | 0.0010 (11) |
C5 | 0.0193 (14) | 0.0162 (13) | 0.0243 (15) | 0.0012 (11) | 0.0036 (11) | 0.0024 (11) |
C6 | 0.0161 (14) | 0.0181 (13) | 0.0269 (15) | 0.0005 (11) | 0.0049 (11) | 0.0008 (11) |
C7 | 0.0216 (16) | 0.0241 (16) | 0.0305 (18) | 0.0036 (12) | 0.0085 (13) | −0.0015 (12) |
Br1—C1 | 1.900 (3) | C5—C6 | 1.527 (4) |
O1—C3 | 1.366 (3) | C5—H5A | 0.9700 |
O1—C4 | 1.441 (3) | C5—H5B | 0.9700 |
C1—C2 | 1.384 (4) | C6—C7 | 1.523 (4) |
C1—C3i | 1.386 (4) | C6—H6A | 0.9700 |
C2—C3 | 1.397 (4) | C6—H6B | 0.9700 |
C2—H2 | 0.9300 | C7—H7A | 0.9600 |
C4—C5 | 1.511 (4) | C7—H7B | 0.9600 |
C4—H4A | 0.9700 | C7—H7C | 0.9600 |
C4—H4B | 0.9700 | ||
C3—O1—C4 | 117.5 (2) | C4—C5—H5A | 109.2 |
C2—C1—C3i | 122.2 (3) | C6—C5—H5A | 109.2 |
C2—C1—Br1 | 118.7 (2) | C4—C5—H5B | 109.2 |
C3i—C1—Br1 | 119.1 (2) | C6—C5—H5B | 109.2 |
C1—C2—C3 | 120.0 (3) | H5A—C5—H5B | 107.9 |
C1—C2—H2 | 120.0 | C7—C6—C5 | 111.5 (2) |
C3—C2—H2 | 120.0 | C7—C6—H6A | 109.3 |
O1—C3—C1i | 117.8 (2) | C5—C6—H6A | 109.3 |
O1—C3—C2 | 124.3 (3) | C7—C6—H6B | 109.3 |
C1i—C3—C2 | 117.8 (3) | C5—C6—H6B | 109.3 |
O1—C4—C5 | 107.3 (2) | H6A—C6—H6B | 108.0 |
O1—C4—H4A | 110.3 | C6—C7—H7A | 109.5 |
C5—C4—H4A | 110.3 | C6—C7—H7B | 109.5 |
O1—C4—H4B | 110.3 | H7A—C7—H7B | 109.5 |
C5—C4—H4B | 110.3 | C6—C7—H7C | 109.5 |
H4A—C4—H4B | 108.5 | H7A—C7—H7C | 109.5 |
C4—C5—C6 | 112.0 (2) | H7B—C7—H7C | 109.5 |
Symmetry code: (i) −x, −y+2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C14H20Br2O2 |
Mr | 380.10 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 150 |
a, b, c (Å) | 8.3685 (4), 12.6395 (5), 7.1083 (3) |
β (°) | 96.461 (5) |
V (Å3) | 747.10 (6) |
Z | 2 |
Radiation type | Cu Kα |
µ (mm−1) | 6.82 |
Crystal size (mm) | 0.07 × 0.06 × 0.01 |
Data collection | |
Diffractometer | Oxford Diffraction Gemini diffractometer |
Absorption correction | Multi-scan (CrysAlis RED; Oxford Diffraction, 2006) |
Tmin, Tmax | 0.647, 0.935 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5426, 1442, 1303 |
Rint | 0.029 |
(sin θ/λ)max (Å−1) | 0.615 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.030, 0.081, 1.07 |
No. of reflections | 1442 |
No. of parameters | 83 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.73, −0.38 |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2006), CrysAlis RED (Oxford Diffraction, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), PLATON (Spek, 2009) and publCIF (Westrip, 2010).
Acknowledgements
The authors thank Universiti Kebangsaan Malaysia and the Ministry of Higher Education, Malaysia for research grants UKM-GUP-BTT-07–26-178 and UKM-FST-06-FRGS0095–2010. This work was also supported by a National Science Fellowship (NSF) for TCH.
References
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Dialkoxy-substituted benzenes such as the title compound (I) are very useful intermediates to synthesize soluble poly(p-phenylene) (Huang et al., 2007; Lightowler & Hird, 2005), thiophene–phenylene co-oligomers (Promarak & Ruchirawat, 2007) and poly(phenylene vinylene) (Brandon et al., 1997), which have wide range of applications in semiconductor and electronics industries.
The title compound is similar to its analog, 1,4-dibromo-2,5-bis(hexyloxy)-benzene (II) (Li et al., 2008). The alkyl chains are nearly coplanar with the benzene ring, with C4—O1—C3—C2 torsion angles of 3.3 (4)°, which is similar to II. However, the title compound is stabilized by intermolecular Br···O interactions [3.2393 (19) Å], which has shorter distance, compared to Br···Br interactions (3.410 Å) found in II. The intermolecular Br···O interaction is shorter than the sum of the Van der Waals radii of the relevant atoms (3.37 Å) and those found in other compound [3.301 (4) Å] (Fun et al. 2010).
In the crystal, nearly linear halogen bond C1–Br1···O1(-x, 1/2 + y, 1/2 - z) [<C1-Br···O159.96 (9)°] link the molecules into a two-dimensional corrugated network along bc plane (Figure 2).