1-Bromo-2-[(E)-2-nitro­ethen­yl]benzene

Abstract

In the title compound, C₈H₆BrNO₂, the dihedral angle between the planes of the benzene ring and the nitro group is 22.99 (12)°. In the crystal, inversion dimers associated by pairs of short Br⋯O contacts [3.2319 (17) Å] occur.

Related literature

For background to nitro-olefins and their synthetic applications, see: Barret & Graboski (1986 ▶); Berner et al. (2002 ▶); Ballini et al. (1992 ▶).

Experimental

Crystal data

• C₈H₆BrNO₂

• M _r = 228.05

• Monoclinic,

• a = 6.9570 (18) Å

• b = 15.646 (2) Å

• c = 7.9470 (13) Å

• β = 109.336 (5)°

• V = 816.2 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 4.99 mm⁻¹

• T = 113 K

• 0.20 × 0.18 × 0.16 mm

Data collection

• Rigaku Saturn724 CCD diffractometer

• Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005 ▶) T _min = 0.435, T _max = 0.502

• 10346 measured reflections

• 1945 independent reflections

• 1466 reflections with I > 2σ(I)

• R _int = 0.042

Refinement

• R[F ² > 2σ(F ²)] = 0.024

• wR(F ²) = 0.056

• S = 1.08

• 1945 reflections

• 109 parameters

• H-atom parameters constrained

• Δρ_max = 0.33 e Å⁻³

• Δρ_min = −0.78 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; 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: CrystalStructure (Rigaku/MSC, 2005 ▶).

Supplementary Material

Supplementary material file. DOI: 10.1107/S1600536811050963/hb6539Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

Comment

Nitro-olefins are useful building blocks in organic synthesis (Barret et al., 1986). Furthermore, the charater of these compounds as electron-deficient alkenes allows easy 1,4-addtion reactions and this opens the way to synthetically useful C—C and C—X (X = N, O) bond-forming reactions (Berner et al. (2002), Ballini et al. (1992)). The title compound, (I), belongs to the class of fuctionalized nitroolefins.

As shown in Fig. 1, the dihedral angle between carbon double bond and phenyl groups is 12.2 (2) °. As shown in Fig. 2, the crystal packing shows the weak O···Br intermolecular interactions.

Experimental

2-Bromobenzaladehyde (39.8 mmol, 7.36 g), nitromethane (99.2 mmol, 5.38 ml), and methanol (16.80 ml) are added to a 3-neck round bottomed flask and cooled to zero degree centigrade. While maintaining the internal reaction temperature between zero and ten degrees centigrade, aqueous 1M NaOH (100.2 mmol, 100.20 ml) is added by an additon funnel and the mixture is stirred for 15 min. Ice water mixture (70.00 ml) is added and the reaction is stirred at zero degree centigrade for 30 min. The reaction mixture is slowly added to aqueous 8M HCl (536.0 mmol, 67.00 ml) and allowed to stir until the rection is confirmed complete by TLC. The reaction mixture is filtered and recrystallized from ethanol to give the product. Colourless prisms of (I) were obtained by slow evaporation of the dichloromethane/n-hexane solutions at room temperature.

Refinement

All the H atoms were positioned geometrically (C—H = 0.95 Å) and refined as riding with U_iso(H) = 1.2U_eq(C).

Figures

Fig. 1.

The molecular structure of (I). Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii.

Fig. 2.

The crystal packing for (I).

Crystal data

C8H6BrNO2	F(000) = 448
Mr = 228.05	Dx = 1.856 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 6.9570 (18) Å	Cell parameters from 2970 reflections
b = 15.646 (2) Å	θ = 2.6–28.0°
c = 7.9470 (13) Å	µ = 4.99 mm−1
β = 109.336 (5)°	T = 113 K
V = 816.2 (3) Å3	Prism, colorless
Z = 4	0.20 × 0.18 × 0.16 mm

Data collection

Rigaku Saturn724 CCD diffractometer	1945 independent reflections
Radiation source: rotating anode	1466 reflections with I > 2σ(I)
multilayer	Rint = 0.042
Detector resolution: 14.22 pixels mm-1	θmax = 27.8°, θmin = 2.6°
ω and φ scans	h = −9→9
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005)	k = −20→20
Tmin = 0.435, Tmax = 0.502	l = −10→10
10346 measured reflections

Refinement

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)] = 0.024	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.056	H-atom parameters constrained
S = 1.08	w = 1/[σ2(Fo2) + (0.020P)2] where P = (Fo2 + 2Fc2)/3
1945 reflections	(Δ/σ)max = 0.003
109 parameters	Δρmax = 0.33 e Å−3
0 restraints	Δρmin = −0.78 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. 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 (Ų)

	x	y	z	Uiso*/Ueq
Br1	0.39712 (4)	0.607142 (14)	0.81215 (3)	0.02051 (8)
O1	0.1113 (2)	0.21839 (10)	0.6270 (2)	0.0218 (4)
O2	0.3362 (2)	0.29119 (10)	0.8336 (2)	0.0238 (4)
N1	0.2150 (3)	0.28344 (11)	0.6807 (2)	0.0153 (4)
C1	0.3043 (3)	0.58570 (14)	0.5620 (3)	0.0141 (5)
C2	0.2914 (3)	0.65593 (14)	0.4508 (3)	0.0153 (5)
H2	0.3316	0.7109	0.5007	0.018*
C3	0.2203 (3)	0.64552 (14)	0.2684 (3)	0.0179 (5)
H3	0.2093	0.6935	0.1925	0.021*
C4	0.1644 (3)	0.56451 (15)	0.1954 (3)	0.0190 (5)
H4	0.1156	0.5571	0.0696	0.023*
C5	0.1804 (3)	0.49484 (14)	0.3071 (3)	0.0160 (5)
H5	0.1438	0.4398	0.2561	0.019*
C6	0.2490 (3)	0.50341 (13)	0.4930 (3)	0.0119 (4)
C7	0.2672 (3)	0.42903 (13)	0.6100 (3)	0.0132 (5)
H7	0.3405	0.4360	0.7334	0.016*
C8	0.1882 (3)	0.35266 (13)	0.5549 (3)	0.0135 (5)
H8	0.1138	0.3435	0.4324	0.016*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.02929 (14)	0.01733 (14)	0.01372 (13)	−0.00098 (11)	0.00552 (10)	−0.00406 (9)
O1	0.0270 (10)	0.0133 (8)	0.0233 (9)	−0.0033 (7)	0.0058 (8)	0.0004 (7)
O2	0.0272 (10)	0.0228 (9)	0.0148 (9)	0.0010 (7)	−0.0020 (7)	0.0036 (7)
N1	0.0178 (10)	0.0113 (10)	0.0182 (10)	0.0032 (8)	0.0079 (8)	0.0012 (8)
C1	0.0107 (11)	0.0190 (12)	0.0120 (11)	0.0007 (9)	0.0032 (9)	−0.0014 (9)
C2	0.0151 (12)	0.0119 (12)	0.0207 (13)	−0.0022 (9)	0.0081 (10)	−0.0021 (9)
C3	0.0178 (12)	0.0158 (12)	0.0207 (13)	−0.0014 (10)	0.0074 (10)	0.0057 (10)
C4	0.0211 (13)	0.0227 (14)	0.0122 (12)	−0.0046 (10)	0.0042 (10)	−0.0008 (10)
C5	0.0173 (12)	0.0146 (12)	0.0161 (12)	−0.0010 (9)	0.0056 (10)	−0.0023 (9)
C6	0.0099 (11)	0.0113 (11)	0.0148 (12)	0.0014 (8)	0.0046 (9)	0.0015 (9)
C7	0.0119 (11)	0.0150 (12)	0.0124 (11)	0.0032 (9)	0.0037 (9)	0.0005 (9)
C8	0.0164 (12)	0.0132 (12)	0.0111 (12)	0.0047 (9)	0.0050 (9)	0.0037 (9)

Geometric parameters (Å, °)

Br1—C1	1.906 (2)	C3—H3	0.9500
O1—N1	1.239 (2)	C4—C5	1.387 (3)
O2—N1	1.234 (2)	C4—H4	0.9500
N1—C8	1.444 (3)	C5—C6	1.401 (3)
C1—C2	1.394 (3)	C5—H5	0.9500
C1—C6	1.402 (3)	C6—C7	1.468 (3)
C2—C3	1.377 (3)	C7—C8	1.328 (3)
C2—H2	0.9500	C7—H7	0.9500
C3—C4	1.395 (3)	C8—H8	0.9500
O2—N1—O1	123.39 (19)	C3—C4—H4	120.1
O2—N1—C8	119.86 (18)	C4—C5—C6	121.8 (2)
O1—N1—C8	116.75 (18)	C4—C5—H5	119.1
C2—C1—C6	121.6 (2)	C6—C5—H5	119.1
C2—C1—Br1	116.81 (16)	C1—C6—C5	116.97 (19)
C6—C1—Br1	121.57 (16)	C1—C6—C7	121.70 (19)
C3—C2—C1	119.9 (2)	C5—C6—C7	121.31 (19)
C3—C2—H2	120.0	C8—C7—C6	124.4 (2)
C1—C2—H2	120.0	C8—C7—H7	117.8
C2—C3—C4	119.9 (2)	C6—C7—H7	117.8
C2—C3—H3	120.0	C7—C8—N1	120.14 (19)
C4—C3—H3	120.0	C7—C8—H8	119.9
C5—C4—C3	119.7 (2)	N1—C8—H8	119.9
C5—C4—H4	120.1
C6—C1—C2—C3	0.9 (3)	Br1—C1—C6—C7	−2.4 (3)
Br1—C1—C2—C3	−178.25 (16)	C4—C5—C6—C1	−1.0 (3)
C1—C2—C3—C4	−1.0 (3)	C4—C5—C6—C7	−179.4 (2)
C2—C3—C4—C5	0.2 (3)	C1—C6—C7—C8	168.8 (2)
C3—C4—C5—C6	0.9 (4)	C5—C6—C7—C8	−13.0 (3)
C2—C1—C6—C5	0.1 (3)	C6—C7—C8—N1	179.9 (2)
Br1—C1—C6—C5	179.22 (16)	O2—N1—C8—C7	−10.9 (3)
C2—C1—C6—C7	178.5 (2)	O1—N1—C8—C7	168.8 (2)