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Acta Crystallogr Sect E Struct Rep Online. 2009 September 1; 65(Pt 9): o2193–o2194.
Published online 2009 August 19. doi:  10.1107/S1600536809031833
PMCID: PMC2970072

1-Dibromo­methyl-4-meth­oxy-2-nitro­benzene

Abstract

The asymmetric unit of the title compound, C8H7Br2NO3, comprises two crystallographically independent mol­ecules (A and B). The nitro groups are twisted from the attached benzene rings, making dihedral angles of 39.26 (9) and 35.90 (9)° in mol­ecules A and B, respectively. In each mol­ecule, the dibromo­methyl group is orientated in such a way that the two Br atoms are tilted away from the benzene ring. An inter­esting features of the crystal structure is the two short Br(...)Br inter­actions which, together with inter­molecular C—H(...)O hydrogen bonds, link the mol­ecules into an extended three-dimensional network. The crystal structure is further stabilized by weak C—H(...)π inter­actions.

Related literature

For general background to and applications of brominated organic compounds, see Augustine et al. (2007 [triangle]); Derdau et al. (2003 [triangle]); Khatuya (2001 [triangle]); Tyeklar et al. (1993 [triangle]). For related structures, see: Fun, Chantrapromma, Maity et al. (2009 [triangle]); Fun, Chantrapromma, Sujith et al. (2009 [triangle]); Yeap et al. (2008 [triangle]). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-o2193-scheme1.jpg

Experimental

Crystal data

  • C8H7Br2NO3
  • M r = 324.97
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o2193-efi1.jpg
  • a = 7.9591 (1) Å
  • b = 11.1949 (2) Å
  • c = 12.2509 (2) Å
  • α = 106.285 (1)°
  • β = 99.691 (1)°
  • γ = 102.401 (1)°
  • V = 992.45 (3) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 8.15 mm−1
  • T = 100 K
  • 0.28 × 0.25 × 0.19 mm

Data collection

  • Bruker SMART APEXII CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2005 [triangle]) T min = 0.210, T max = 0.311 (expected range = 0.147–0.218)
  • 32659 measured reflections
  • 8800 independent reflections
  • 7332 reflections with I > 2σ(I)
  • R int = 0.027

Refinement

  • R[F 2 > 2σ(F 2)] = 0.026
  • wR(F 2) = 0.066
  • S = 1.01
  • 8800 reflections
  • 261 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.78 e Å−3
  • Δρmin = −0.47 e Å−3

Data collection: APEX2 (Bruker, 2005 [triangle]); cell refinement: SAINT (Bruker, 2005 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 [triangle]).

Table 1
Selected interatomic distances (Å)
Table 2
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809031833/wn2343sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809031833/wn2343Isup2.hkl

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

Acknowledgments

HKF and JHG thank Universiti Sains Malaysia (USM) for the Research Universiti Golden Goose Grant (No. 1001/PFIZIK/811012). JHG thanks USM for the award of a USM Fellowship. AMI is grateful to the Director, NITK, Surathkal, India, for providing research facilities.

supplementary crystallographic information

Comment

Brominated organic compounds are important synthetic intermediates and products in organic chemistry (Augustine et al., 2007). They are found in C-C coupling reactions, as precursors to organometallic species and in nucleophilic substitutions (Tyeklar et al., 1993). They are also used for the synthesis of useful pharmaceutical materials and agrochemicals (Derdau et al., 2003). However the use of molecular bromine as an electrophilic brominating reagent has several drawbacks arising from its toxic and corrosive nature and its high reactivity (Tyeklar et al., 1993). Alternative brominating reagents such as N-bromosuccinimide make for easier handling and result in improved selectivity (Khatuya, 2001).

In the asymmetric unit of the title compound, there are two crystallographically independent molecules, designated A and B (Fig. 1). In each molecule, the nitro group is twisted from the mean plane of the C1-C6 benzene ring, as shown by the dihedral angle formed between the mean plane through C5/N1/O2/O3 and the C1-C6 benzene ring of 39.26 (9)° in molecule A; the comparable angle is 35.90 (9)° for molecule B. Meanwhile, the dibromomethyl group is orientated in such a way that the two Br atoms are tilted away from the benzene ring. The bond lengths and angles are comparable to those found in related structures (Fun, Chantrapromma, Maity et al., 2009; Fun, Chantrapromma, Sujith et al., 2009; Yeap et al., 2008).

In the crystal structure (Fig. 2), the interesting features are the Br1A···Br2B and Br2A···Br1B short interactions (Table 1). Together with intermolecular C7A—H7A···O2B and C8B—H8BA···O1A hydrogen bonds (Table 2), they link the molecules into a three-dimensional extended network. The crystal structure is further stabilized by weak C8A—H8AA···Cg2 interactions (Table 2).

Experimental

Benzoyl peroxide (0.20 g, 10 %) and N-bromosuccinimide (6.38 g, 0.0358 mol) were added in portions to a solution of 4-methyl-2-nitroanisole (2.00 g, 0.0119 mol) in CCl4 (20 ml). The reaction mixture was heated at 85 °C under a nitrogen atmosphere for 12 h. The reaction mass was cooled and filtered. The filtrate was concentrated to produce a crude product. The latter was recrystallized with hexane to afford the title compound as a colourless crystalline solid. The yield was 3.50 g, 92 %. M.p. 370–373 K.

Refinement

The H-atoms bound to C7A and C7B were located from the difference Fourier map and allowed to refine freely. The other H-atoms were placed in calculated positions, with C—H = 0.93 Å, Uiso(H) = 1.2Ueq(C) for aromatic, and C—H = 0.96 Å, Uiso(H) = 1.5Ueq(C) for methyl group; these aromatic and methyl group H atoms were refined as riding on their parent atoms. A rotating group model was used for the methyl group.

Figures

Fig. 1.
The molecular structure of the asymmetric unit of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme. Hydrogen atoms are shown as spheres of arbitrary radius.
Fig. 2.
Three-dimensional extended network, viewed along the a axis. Intermolecular interactions are shown as dashed lines.

Crystal data

C8H7Br2NO3Z = 4
Mr = 324.97F(000) = 624
Triclinic, P1Dx = 2.175 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.9591 (1) ÅCell parameters from 9885 reflections
b = 11.1949 (2) Åθ = 2.2–35.1°
c = 12.2509 (2) ŵ = 8.15 mm1
α = 106.285 (1)°T = 100 K
β = 99.691 (1)°Block, colourless
γ = 102.401 (1)°0.28 × 0.25 × 0.19 mm
V = 992.45 (3) Å3

Data collection

Bruker SMART APEXII CCD area-detector diffractometer8800 independent reflections
Radiation source: fine-focus sealed tube7332 reflections with I > 2σ(I)
graphiteRint = 0.027
[var phi] and ω scansθmax = 35.3°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2005)h = −12→12
Tmin = 0.210, Tmax = 0.311k = −17→18
32659 measured reflectionsl = −19→19

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.026Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.066H atoms treated by a mixture of independent and constrained refinement
S = 1.01w = 1/[σ2(Fo2) + (0.0361P)2 + 0.2346P] where P = (Fo2 + 2Fc2)/3
8800 reflections(Δ/σ)max = 0.004
261 parametersΔρmax = 0.78 e Å3
0 restraintsΔρmin = −0.47 e Å3

Special details

Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1)K.
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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)

xyzUiso*/Ueq
Br1A0.79537 (2)1.230776 (16)0.197580 (14)0.02458 (4)
Br2A0.90786 (2)1.101536 (16)0.387687 (13)0.02180 (4)
O1A0.76010 (16)0.62902 (12)−0.10724 (10)0.0229 (2)
O2A0.30267 (16)0.76549 (13)0.10327 (11)0.0265 (2)
O3A0.37293 (16)0.96938 (13)0.11963 (11)0.0257 (2)
N1A0.40781 (17)0.86506 (14)0.10586 (11)0.0208 (2)
C1A0.8937 (2)0.94163 (16)0.11837 (13)0.0209 (3)
H1AA0.99901.00610.15780.025*
C2A0.8985 (2)0.83283 (16)0.03310 (13)0.0216 (3)
H2AA1.00520.82600.01420.026*
C3A0.7427 (2)0.73241 (15)−0.02523 (13)0.0195 (3)
C4A0.58321 (19)0.74374 (15)0.00283 (13)0.0188 (2)
H4AA0.47920.6770−0.03350.023*
C5A0.58299 (19)0.85699 (15)0.08631 (13)0.0185 (2)
C6A0.73536 (19)0.95856 (15)0.14790 (13)0.0184 (2)
C7A0.7370 (2)1.07568 (15)0.24351 (13)0.0196 (3)
C8A0.6054 (2)0.52136 (17)−0.16335 (15)0.0256 (3)
H8AA0.63440.4546−0.21930.038*
H8AB0.51410.5491−0.20290.038*
H8AC0.56400.4883−0.10550.038*
Br1B−0.20637 (2)0.726206 (17)0.325018 (14)0.02462 (4)
Br2B−0.10244 (2)0.523519 (16)0.125556 (13)0.02342 (4)
O1B0.50849 (16)0.63292 (12)0.60857 (11)0.0243 (2)
O2B0.49443 (16)0.92884 (12)0.36858 (11)0.0252 (2)
O3B0.22098 (17)0.93622 (12)0.34859 (12)0.0261 (2)
N1B0.33898 (17)0.88484 (13)0.36914 (11)0.0197 (2)
C1B0.1045 (2)0.56681 (15)0.38962 (13)0.0206 (3)
H1BA−0.00190.50170.35750.025*
C2B0.2309 (2)0.55536 (16)0.47501 (14)0.0215 (3)
H2BA0.20810.48400.50050.026*
C3B0.3935 (2)0.65079 (16)0.52360 (13)0.0200 (3)
C4B0.4281 (2)0.75603 (15)0.48395 (13)0.0199 (3)
H4BA0.53700.81860.51310.024*
C5B0.29538 (19)0.76575 (15)0.39929 (13)0.0180 (2)
C6B0.13101 (19)0.67357 (15)0.34948 (13)0.0185 (2)
C7B−0.0114 (2)0.68337 (16)0.25833 (13)0.0203 (3)
C8B0.6731 (2)0.73163 (19)0.66117 (16)0.0289 (3)
H8BA0.74360.70880.71960.043*
H8BB0.65040.81260.69710.043*
H8BC0.73590.73970.60210.043*
H7A0.627 (3)1.0704 (19)0.2645 (17)0.013 (4)*
H7B0.022 (3)0.747 (2)0.226 (2)0.028 (6)*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Br1A0.03013 (8)0.01907 (7)0.02323 (7)0.00585 (6)0.00401 (6)0.00714 (6)
Br2A0.01964 (7)0.02534 (8)0.01851 (6)0.00619 (5)0.00280 (5)0.00539 (5)
O1A0.0221 (5)0.0217 (5)0.0231 (5)0.0078 (4)0.0056 (4)0.0033 (4)
O2A0.0185 (5)0.0262 (6)0.0315 (6)0.0021 (4)0.0067 (4)0.0068 (5)
O3A0.0211 (5)0.0255 (6)0.0293 (6)0.0111 (4)0.0033 (4)0.0052 (5)
N1A0.0171 (5)0.0232 (6)0.0198 (5)0.0060 (5)0.0029 (4)0.0043 (5)
C1A0.0167 (6)0.0229 (7)0.0215 (6)0.0049 (5)0.0037 (5)0.0060 (5)
C2A0.0180 (6)0.0255 (7)0.0210 (6)0.0071 (5)0.0051 (5)0.0062 (5)
C3A0.0206 (6)0.0198 (7)0.0185 (6)0.0076 (5)0.0039 (5)0.0061 (5)
C4A0.0173 (6)0.0179 (6)0.0196 (6)0.0050 (5)0.0020 (5)0.0051 (5)
C5A0.0158 (6)0.0200 (7)0.0199 (6)0.0062 (5)0.0037 (5)0.0063 (5)
C6A0.0173 (6)0.0189 (6)0.0186 (6)0.0051 (5)0.0036 (5)0.0060 (5)
C7A0.0191 (6)0.0186 (6)0.0189 (6)0.0034 (5)0.0034 (5)0.0046 (5)
C8A0.0278 (8)0.0205 (7)0.0260 (7)0.0066 (6)0.0064 (6)0.0042 (6)
Br1B0.01982 (7)0.02733 (8)0.02389 (7)0.00989 (6)0.00277 (5)0.00308 (6)
Br2B0.02590 (7)0.02424 (8)0.01841 (6)0.00830 (6)0.00365 (5)0.00441 (5)
O1B0.0208 (5)0.0264 (6)0.0264 (5)0.0062 (4)0.0013 (4)0.0125 (5)
O2B0.0205 (5)0.0262 (6)0.0282 (6)0.0014 (4)0.0061 (4)0.0118 (5)
O3B0.0262 (6)0.0224 (6)0.0327 (6)0.0100 (5)0.0059 (5)0.0122 (5)
N1B0.0209 (6)0.0174 (6)0.0202 (5)0.0043 (5)0.0045 (4)0.0065 (4)
C1B0.0197 (6)0.0189 (7)0.0225 (6)0.0038 (5)0.0042 (5)0.0076 (5)
C2B0.0211 (6)0.0197 (7)0.0251 (7)0.0055 (5)0.0058 (5)0.0094 (5)
C3B0.0187 (6)0.0211 (7)0.0216 (6)0.0073 (5)0.0049 (5)0.0077 (5)
C4B0.0181 (6)0.0200 (7)0.0211 (6)0.0050 (5)0.0040 (5)0.0065 (5)
C5B0.0191 (6)0.0165 (6)0.0196 (6)0.0055 (5)0.0057 (5)0.0066 (5)
C6B0.0170 (6)0.0190 (6)0.0192 (6)0.0051 (5)0.0042 (5)0.0058 (5)
C7B0.0193 (6)0.0199 (7)0.0208 (6)0.0048 (5)0.0039 (5)0.0065 (5)
C8B0.0228 (7)0.0303 (9)0.0301 (8)0.0047 (6)−0.0012 (6)0.0112 (7)

Geometric parameters (Å, °)

Br1A—C7A1.9587 (15)Br1B—C7B1.9576 (16)
Br2A—C7A1.9462 (15)Br2B—C7B1.9460 (16)
O1A—C3A1.3535 (19)O1B—C3B1.3547 (19)
O1A—C8A1.433 (2)O1B—C8B1.431 (2)
O2A—N1A1.2306 (18)O2B—N1B1.2314 (17)
O3A—N1A1.2305 (19)O3B—N1B1.2288 (18)
N1A—C5A1.4710 (19)N1B—C5B1.4680 (19)
C1A—C2A1.377 (2)C1B—C2B1.378 (2)
C1A—C6A1.405 (2)C1B—C6B1.404 (2)
C1A—H1AA0.9300C1B—H1BA0.9300
C2A—C3A1.402 (2)C2B—C3B1.401 (2)
C2A—H2AA0.9300C2B—H2BA0.9300
C3A—C4A1.392 (2)C3B—C4B1.388 (2)
C4A—C5A1.388 (2)C4B—C5B1.395 (2)
C4A—H4AA0.9300C4B—H4BA0.9300
C5A—C6A1.397 (2)C5B—C6B1.395 (2)
C6A—C7A1.489 (2)C6B—C7B1.497 (2)
C7A—H7A0.948 (19)C7B—H7B0.92 (2)
C8A—H8AA0.9600C8B—H8BA0.9600
C8A—H8AB0.9600C8B—H8BB0.9600
C8A—H8AC0.9600C8B—H8BC0.9600
Br1A···Br2Bi3.5915 (3)Br2A···Br1Bii3.6279 (2)
C3A—O1A—C8A117.29 (13)C3B—O1B—C8B116.75 (13)
O3A—N1A—O2A123.97 (14)O3B—N1B—O2B123.87 (14)
O3A—N1A—C5A118.23 (13)O3B—N1B—C5B118.83 (12)
O2A—N1A—C5A117.75 (14)O2B—N1B—C5B117.28 (13)
C2A—C1A—C6A122.27 (14)C2B—C1B—C6B122.16 (14)
C2A—C1A—H1AA118.9C2B—C1B—H1BA118.9
C6A—C1A—H1AA118.9C6B—C1B—H1BA118.9
C1A—C2A—C3A120.06 (14)C1B—C2B—C3B120.25 (14)
C1A—C2A—H2AA120.0C1B—C2B—H2BA119.9
C3A—C2A—H2AA120.0C3B—C2B—H2BA119.9
O1A—C3A—C4A124.35 (14)O1B—C3B—C4B124.10 (14)
O1A—C3A—C2A115.97 (13)O1B—C3B—C2B116.25 (14)
C4A—C3A—C2A119.68 (14)C4B—C3B—C2B119.65 (14)
C5A—C4A—C3A118.44 (14)C3B—C4B—C5B118.43 (14)
C5A—C4A—H4AA120.8C3B—C4B—H4BA120.8
C3A—C4A—H4AA120.8C5B—C4B—H4BA120.8
C4A—C5A—C6A123.78 (14)C4B—C5B—C6B123.70 (14)
C4A—C5A—N1A115.23 (13)C4B—C5B—N1B114.52 (13)
C6A—C5A—N1A120.98 (14)C6B—C5B—N1B121.73 (13)
C5A—C6A—C1A115.70 (14)C5B—C6B—C1B115.76 (14)
C5A—C6A—C7A123.71 (13)C5B—C6B—C7B123.88 (14)
C1A—C6A—C7A120.52 (13)C1B—C6B—C7B120.36 (13)
C6A—C7A—Br2A111.59 (11)C6B—C7B—Br2B111.47 (11)
C6A—C7A—Br1A110.77 (10)C6B—C7B—Br1B110.83 (10)
Br2A—C7A—Br1A108.66 (7)Br2B—C7B—Br1B109.65 (7)
C6A—C7A—H7A113.2 (12)C6B—C7B—H7B115.7 (15)
Br2A—C7A—H7A104.8 (12)Br2B—C7B—H7B105.1 (15)
Br1A—C7A—H7A107.5 (12)Br1B—C7B—H7B103.7 (15)
O1A—C8A—H8AA109.5O1B—C8B—H8BA109.5
O1A—C8A—H8AB109.5O1B—C8B—H8BB109.5
H8AA—C8A—H8AB109.5H8BA—C8B—H8BB109.5
O1A—C8A—H8AC109.5O1B—C8B—H8BC109.5
H8AA—C8A—H8AC109.5H8BA—C8B—H8BC109.5
H8AB—C8A—H8AC109.5H8BB—C8B—H8BC109.5
C6A—C1A—C2A—C3A−1.9 (2)C6B—C1B—C2B—C3B−1.1 (2)
C8A—O1A—C3A—C4A−3.9 (2)C8B—O1B—C3B—C4B1.5 (2)
C8A—O1A—C3A—C2A176.29 (14)C8B—O1B—C3B—C2B−178.30 (15)
C1A—C2A—C3A—O1A−179.68 (14)C1B—C2B—C3B—O1B178.77 (15)
C1A—C2A—C3A—C4A0.5 (2)C1B—C2B—C3B—C4B−1.1 (2)
O1A—C3A—C4A—C5A−178.01 (14)O1B—C3B—C4B—C5B−177.36 (15)
C2A—C3A—C4A—C5A1.8 (2)C2B—C3B—C4B—C5B2.4 (2)
C3A—C4A—C5A—C6A−2.9 (2)C3B—C4B—C5B—C6B−1.9 (2)
C3A—C4A—C5A—N1A176.35 (13)C3B—C4B—C5B—N1B175.71 (14)
O3A—N1A—C5A—C4A−139.68 (14)O3B—N1B—C5B—C4B−142.98 (15)
O2A—N1A—C5A—C4A37.79 (19)O2B—N1B—C5B—C4B35.46 (19)
O3A—N1A—C5A—C6A39.6 (2)O3B—N1B—C5B—C6B34.7 (2)
O2A—N1A—C5A—C6A−142.94 (15)O2B—N1B—C5B—C6B−146.90 (14)
C4A—C5A—C6A—C1A1.6 (2)C4B—C5B—C6B—C1B−0.1 (2)
N1A—C5A—C6A—C1A−177.63 (13)N1B—C5B—C6B—C1B−177.56 (14)
C4A—C5A—C6A—C7A−175.35 (14)C4B—C5B—C6B—C7B−179.76 (15)
N1A—C5A—C6A—C7A5.5 (2)N1B—C5B—C6B—C7B2.8 (2)
C2A—C1A—C6A—C5A0.9 (2)C2B—C1B—C6B—C5B1.6 (2)
C2A—C1A—C6A—C7A177.90 (14)C2B—C1B—C6B—C7B−178.73 (15)
C5A—C6A—C7A—Br2A124.47 (14)C5B—C6B—C7B—Br2B130.42 (13)
C1A—C6A—C7A—Br2A−52.30 (17)C1B—C6B—C7B—Br2B−49.18 (17)
C5A—C6A—C7A—Br1A−114.33 (14)C5B—C6B—C7B—Br1B−107.15 (14)
C1A—C6A—C7A—Br1A68.89 (16)C1B—C6B—C7B—Br1B73.24 (17)

Symmetry codes: (i) x+1, y+1, z; (ii) −x+1, −y+2, −z+1.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C7A—H7A···O2B0.95 (2)2.47 (2)3.134 (2)126.8 (17)
C8B—H8BA···O1Aiii0.962.523.370 (2)148
C8A—H8AA···Cg2iv0.962.953.839 (2)155

Symmetry codes: (iii) x, y, z+1; (iv) −x+1, −y+1, −z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WN2343).

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