1,4-Di­bromo­butane-2,3-dione

The asymmetric unit of the title compound, C₄H₄Br₂O₂, contains one half-mol­ecule, being located about a centre of inversion. In the crystal, there are no significant inter­molecular inter­actions.

Related literature

For the uses of 1,4-dibromo­butane-2,3-dione, see: Gogte et al. (1967). For the synthesis of 1,4-dibromo­butane-2,3-dione, see: Ruggli & Herzog (1946). For the cystal structure of the 1,4-di­chloro analogue, see: Ducourant et al. (1986). For bond–length data, see: Allen et al. (1987).

Experimental

Crystal data

• C₄H₄Br₂O₂

• M_r = 243.89

• Orthorhombic, P b c a

• a = 6.945 (1) Å

• b = 5.542 (1) Å

• c = 17.238 (3) Å

• V = 663.5 (2) ų

• Z = 4

• Mo Kα radiation

• μ = 12.13 mm⁻¹

• T = 298 K

• 0.10 × 0.10 × 0.10 mm

Data collection

• Enraf–Nonius CAD-4 diffractometer

• Absorption correction: ψ scan (North et al., 1968) T_min = 0.195, T_max = 0.377

• 614 measured reflections

• 614 independent reflections

• 319 reflections with I > 2σ(I)

• R_int = 0.077

• 3 standard reflections every 120 min intensity decay: 1%

Refinement

• R[F² > 2σ(F²)] = 0.065

• wR(F²) = 0.108

• S = 0.93

• 614 reflections

• 37 parameters

• 1 restraint

• H-atom parameters constrained

• Δρ_max = 0.65 e Å⁻³

• Δρ_min = −0.60 e Å⁻³

Data collection: CAD-4 Software (Enraf–Nonius, 1985); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995); 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.

Supporting information

S1. Comment

1,4-Dibromobutane-2,3-dione and its derivatives are important intermediates for the synthesis of compounds possessing promising anticancer activity, which is attributed to their likely interference in the hexose-monophosphate (HMP) pathway (Gogte et al., 1967). We report herein on the crystal structure of the title compound.

In the title molecule, Fig. 1, the bond lengths (Allen et al., 1987) and angles are within normal ranges. The asymmetric unit contains one half-molecule, being located on a centre of inversion. It can be compared to the 1,4-dichloro derivative that crystallized in the monoclinic space group P2₁/c (Ducourant et al., 1986) but which also possesses inversion symmetry.

In the crystal, there are no significant intermolecular interactions (Fig. 2).

Related literature

For the uses of 1,4-dibromobutane-2,3-dione, see: Gogte et al. (1967). For the synthesis of 1,4-dibromobutane-2,3-dione, see: Ruggli & Herzog (1946). For the cystal structure of the 1,4-dichloro analogue, see: Ducourant et al. (1986). For bond–length data, see: Allen et al. (1987).

S2. Experimental

1,4-Dibromobutane-2,3-dione was prepared by the method reported in the literature (Ruggli & Herzog, 1946). Yellow plate-like crystals were obtained by dissolving the title compound (0.50 g, 2.05 mmol) in dichloromethane (30 ml) and evaporating the solvent slowly at room temperature for ca. 2 days.

S3. Refinement

The methylene H atoms were positioned geometrically and refined as riding atoms: C-H = 0.97 Å, with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: CAD-4 Software (Enraf–Nonius, 1985); cell refinement: CAD-4 Software (Enraf–Nonius, 1985); data reduction: XCAD4 (Harms & Wocadlo, 1995); 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

	Fig. 1. The molecular structure of the title molecule, with the atom numbering. Displacement ellipsoids are drawn at the 50% probability level [Symmetry code: (a) -x+2, -y+1, -z+1].
	Fig. 2. A view along the a axis of the crystal packing of the title compound.

1,4-Dibromobutane-2,3-dione

Crystal data

C4H4Br2O2	Dx = 2.442 Mg m^−3
Mr = 243.89	Melting point < 395 K
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 25 reflections
a = 6.945 (1) Å	θ = 9–14°
b = 5.542 (1) Å	µ = 12.13 mm^−1
c = 17.238 (3) Å	T = 298 K
V = 663.5 (2) Å^3	Cube, yellow
Z = 4	0.10 × 0.10 × 0.10 mm
F(000) = 456

Data collection

Enraf–Nonius CAD-4 diffractometer	319 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.077
Graphite monochromator	θmax = 25.4°, θmin = 2.4°
ω/2θ scans	h = 0→8
Absorption correction: ψ scan (North et al., 1968)	k = −6→6
Tmin = 0.195, Tmax = 0.377	l = −20→20
614 measured reflections	3 standard reflections every 120 min
614 independent reflections	intensity decay: 1%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.065	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.108	H-atom parameters constrained
S = 0.93	w = 1/[σ^2(Fo^2) + (0.P)^2] where P = (Fo^2 + 2Fc^2)/3
614 reflections	(Δ/σ)max < 0.001
37 parameters	Δρmax = 0.65 e Å^−3
1 restraint	Δρmin = −0.60 e Å^−3

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Br	0.96430 (19)	0.17863 (19)	0.67746 (8)	0.0634 (5)
O	0.8640 (13)	0.2368 (15)	0.5056 (4)	0.062 (2)
C1	1.0276 (16)	0.4425 (18)	0.6134 (6)	0.055 (3)
H1A	0.9689	0.5875	0.6342	0.066*
H1B	1.1661	0.4652	0.6138	0.066*
C2	0.9577 (15)	0.4056 (11)	0.5267 (6)	0.039 (2)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br	0.0755 (7)	0.0501 (7)	0.0647 (9)	−0.0027 (7)	0.0041 (7)	0.0097 (6)
O	0.076 (5)	0.036 (3)	0.073 (6)	−0.026 (5)	−0.019 (5)	0.007 (3)
C1	0.045 (6)	0.068 (7)	0.052 (7)	0.000 (6)	0.009 (6)	−0.016 (7)
C2	0.033 (5)	0.028 (4)	0.057 (7)	0.013 (6)	0.023 (5)	0.007 (5)

Geometric parameters (Å, º)

Br—C1	1.885 (10)	C1—H1A	0.9700
O—C2	1.196 (11)	C1—H1B	0.9700
C1—C2	1.585 (9)	C2—C2^i	1.512 (16)
C2—C1—Br	112.4 (6)	H1A—C1—H1B	107.9
C2—C1—H1A	109.1	O—C2—C2^i	124.6 (12)
Br—C1—H1A	109.1	O—C2—C1	123.7 (8)
C2—C1—H1B	109.1	C2^i—C2—C1	111.4 (10)
Br—C1—H1B	109.1
Br—C1—C2—O	4.7 (13)	Br—C1—C2—C2^i	−169.0 (8)

Symmetry code: (i) −x+2, −y+1, −z+1.