2,5-Di-bromo-3,6-dimeth-oxycyclo-hexa-2,5-diene-1,4-dione.

In the structure of the title compound, C8H6Br2O4, the complete mol-ecule is generated by the application of a centre of inversion. The mol-ecule is planar (r.m.s. deviation for all non-H atoms but methyl C = 0.0358 Å), with only the methyl groups being deviated from the plane [by ±0.321 (4) Å]. In the crystal packing, Br⋯O(methoxy) halogen bonds [3.2407 (19) Å] connect molecules into supramolecular layers parallel to (101).

Related literature

For the synthesis of the title compound, see: Viault et al. (2011 ▶). For the structure of bromanilic acid, see: Robl (1987 ▶). For similar structures with a 2,5-cyclo­hexa­diene-1,4-dione core, see: Nakatsuji et al. (2009 ▶). For an article dealing with the biological relevance of this type of compound, see: Viault et al. (2013 ▶). For papers using the title compound as a synthetic precursor, see: Khan & Driscoll (1976 ▶); Tatsuta et al. (2001 ▶); Kasahara & Kondo (2006 ▶); Gan et al. (2009 ▶). For metalla-assemblies obtained with analogous building blocks, see: Gupta et al. (2014 ▶); Therrien (2009 ▶).

Experimental

Crystal data

C8H6Br2O4

M = 325.95

Monoclinic,

a = 9.4456 (9) Å

b = 5.4877 (3) Å

c = 10.0341 (9) Å

β = 113.846 (7)°

V = 475.71 (7) Å3

Z = 2

Mo Kα radiation

μ = 8.50 mm−1

T = 173 K

0.23 × 0.21 × 0.20 mm

Data collection

Stoe IPDS diffractometer

Absorption correction: part of the refinement model (ΔF) (DIFABS; Walker & Stuart, 1983 ▶) T min = 0.246, T max = 0.704

8772 measured reflections

1284 independent reflections

1144 reflections with I > 2σ(I)

R int = 0.071

Refinement

R[F 2 > 2σ(F 2)] = 0.028

wR(F 2) = 0.067

S = 1.04

1284 reflections

65 parameters

H-atom parameters constrained

Δρmax = 0.86 e Å−3

Δρmin = −0.98 e Å−3

Data collection: EXPOSE (Stoe & Cie, 2000 ▶); cell refinement: CELL (Stoe & Cie, 2000 ▶); data reduction: INTEGRATE (Stoe & Cie, 2000 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536814011787/tk5317sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814011787/tk5317Isup2.hkl

Click here for additional data file.

Supporting information file. DOI: 10.1107/S1600536814011787/tk5317Isup3.cml

CCDC reference: 1004507

Additional supporting information: crystallographic information; 3D view; checkCIF report

C8H6Br2O4	F(000) = 312
Mr = 325.95	Dx = 2.276 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 7998 reflections
a = 9.4456 (9) Å	θ = 2.4–25.9°
b = 5.4877 (3) Å	µ = 8.50 mm−1
c = 10.0341 (9) Å	T = 173 K
β = 113.846 (7)°	Block, red
V = 475.71 (7) Å3	0.23 × 0.21 × 0.20 mm
Z = 2

Stoe IPDS diffractometer	1284 independent reflections
Radiation source: fine-focus sealed tube	1144 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.071
Detector resolution: 0 pixels mm-1	θmax = 29.2°, θmin = 2.5°
φ oscillation scans	h = −12→12
Absorption correction: part of the refinement model (ΔF) (DIFABS; Walker & Stuart, 1983)	k = −7→7
Tmin = 0.246, Tmax = 0.704	l = −13→13
8772 measured reflections

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)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.067	H-atom parameters constrained
S = 1.04	w = 1/[σ2(Fo2) + (0.0431P)2] where P = (Fo2 + 2Fc2)/3
1284 reflections	(Δ/σ)max < 0.001
65 parameters	Δρmax = 0.86 e Å−3
0 restraints	Δρmin = −0.98 e Å−3

Experimental. A crystal was mounted at 173 K on a Stoe Image Plate Diffraction System (Stoe & Cie, 2000) using Mo Kα graphite monochromated radiation. Image plate distance 100 mm, φ oscillation scans 0 - 180°, step Δφ = 1.2°, 3 minutes per frame.

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	0.14128 (3)	0.21073 (5)	0.79296 (3)	0.02303 (10)
C2	−0.0827 (3)	0.2940 (4)	0.9112 (3)	0.0197 (4)
C4	−0.3943 (3)	0.2112 (5)	0.9080 (3)	0.0253 (5)
H4A	−0.4045	0.2467	0.8109	0.038*
H4B	−0.4925	0.2333	0.9138	0.038*
H4C	−0.3608	0.0457	0.9320	0.038*
O2	−0.2815 (2)	0.3740 (4)	1.00971 (19)	0.0262 (4)
O1	−0.1483 (2)	0.1143 (4)	0.8426 (2)	0.0332 (4)
C1	0.0654 (3)	0.3806 (4)	0.9134 (2)	0.0176 (4)
C3	−0.1485 (2)	0.4344 (4)	1.0024 (2)	0.0174 (4)

	U11	U22	U33	U12	U13	U23
Br1	0.02309 (14)	0.02542 (15)	0.02416 (15)	0.00012 (9)	0.01326 (10)	−0.00545 (8)
C2	0.0212 (11)	0.0197 (10)	0.0193 (11)	−0.0009 (8)	0.0093 (9)	−0.0011 (8)
C4	0.0178 (10)	0.0290 (12)	0.0266 (12)	−0.0072 (9)	0.0064 (9)	−0.0016 (9)
O2	0.0216 (8)	0.0326 (9)	0.0283 (9)	−0.0113 (7)	0.0143 (7)	−0.0098 (8)
O1	0.0311 (10)	0.0297 (10)	0.0443 (11)	−0.0119 (8)	0.0209 (9)	−0.0171 (9)
C1	0.0185 (10)	0.0190 (10)	0.0169 (9)	0.0013 (8)	0.0090 (8)	−0.0011 (8)
C3	0.0176 (9)	0.0184 (10)	0.0177 (9)	−0.0004 (8)	0.0086 (8)	0.0012 (7)

Br1—C1	1.882 (2)	C4—H4B	0.9600
C2—O1	1.219 (3)	C4—H4C	0.9600
C2—C1	1.469 (3)	O2—C3	1.330 (3)
C2—C3	1.509 (3)	C1—C3i	1.351 (3)
C4—O2	1.448 (3)	C3—C1i	1.351 (3)
C4—H4A	0.9600
O1—C2—C1	122.3 (2)	H4B—C4—H4C	109.5
O1—C2—C3	121.0 (2)	C3—O2—C4	123.90 (19)
C1—C2—C3	116.68 (19)	C3i—C1—C2	124.14 (19)
O2—C4—H4A	109.5	C3i—C1—Br1	119.87 (16)
O2—C4—H4B	109.5	C2—C1—Br1	115.96 (16)
H4A—C4—H4B	109.5	O2—C3—C1i	118.4 (2)
O2—C4—H4C	109.5	O2—C3—C2	122.4 (2)
H4A—C4—H4C	109.5	C1i—C3—C2	119.05 (19)
O1—C2—C1—C3i	−174.0 (2)	C4—O2—C3—C2	−15.5 (4)
C3—C2—C1—C3i	4.2 (4)	O1—C2—C3—O2	−1.7 (4)
O1—C2—C1—Br1	4.2 (3)	C1—C2—C3—O2	−179.9 (2)
C3—C2—C1—Br1	−177.59 (16)	O1—C2—C3—C1i	174.3 (2)
C4—O2—C3—C1i	168.5 (2)	C1—C2—C3—C1i	−4.0 (4)