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Acta Crystallogr Sect E Struct Rep Online. 2008 January 1; 64(Pt 1): o76.
Published online 2007 December 6. doi:  10.1107/S160053680705516X
PMCID: PMC2915033

2,3-Bis(4-bromo­phen­yl)quinoxaline

Abstract

The title compound, C20H12Br2N2, was prepared by the reaction of 1-(3-bromo­phen­yl)-2-(4-bromo­phen­yl)ethane-1,2-dione with o-phenyl­enediamine in refluxing ethanol. In the mol­ecule, all bond lengths and angles are within normal ranges. The dihedral angle between the two benzene rings is 34.89 (1)°. The dihedral angles between the benzene rings and the quinoxaline system are 57.23 (1) and 36.75 (1)°. The crystal packing is stabilized by van der Waals forces.

Related literature

For related literature, see: Brock et al. (1999 [triangle]); Dailey et al. (2001 [triangle]); Guillon et al. (1998 [triangle]); Kim et al. (1993 [triangle]); Patel et al. (2000 [triangle]); Rong et al. (2006 [triangle]).

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Object name is e-64-00o76-scheme1.jpg

Experimental

Crystal data

  • C20H12Br2N2
  • M r = 440.14
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-00o76-efi1.jpg
  • a = 6.0830 (12) Å
  • b = 12.018 (2) Å
  • c = 12.323 (3) Å
  • α = 105.47 (3)°
  • β = 91.89 (3)°
  • γ = 97.47 (3)°
  • V = 858.7 (3) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 4.72 mm−1
  • T = 293 (2) K
  • 0.20 × 0.18 × 0.15 mm

Data collection

  • Enraf–Nonius CAD-4 diffractometer
  • Absorption correction: ψ scan (North et al., 1968 [triangle]) T min = 0.404, T max = 0.492
  • 3338 measured reflections
  • 2888 independent reflections
  • 1824 reflections with I > 2σ(I)
  • R int = 0.027
  • 3 standard reflections every 100 reflections intensity decay: none

Refinement

  • R[F 2 > 2σ(F 2)] = 0.046
  • wR(F 2) = 0.128
  • S = 1.06
  • 2888 reflections
  • 217 parameters
  • H-atom parameters constrained
  • Δρmax = 0.56 e Å−3
  • Δρmin = −0.74 e Å−3

Data collection: CAD-4 Software (Enraf–Nonius, 1989 [triangle]); cell refinement: CAD-4 Software; data reduction: NRCVAX (Gabe et al., 1989 [triangle]); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997 [triangle]); molecular graphics: SHELXTL/PC (Sheldrick, 1990 [triangle]); software used to prepare material for publication: WinGX (Farrugia, 1999 [triangle]).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053680705516X/hg2324sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053680705516X/hg2324Isup2.hkl

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

Acknowledgments

The authors thank the Natural Science Foundation of Shandong Province (grant No. Y2005B04).

supplementary crystallographic information

Comment

Quinoxaline derivatives are an important class of nitrogen containing heterocycles and constitute useful intermediates in organic synthesis which have been reported for their applications in the fields of dyes (Brock et al., 1999) and have also been used as building blocks for the synthesis of organic semiconductors (Dailey et al., 2001). Tetrahydroquinoxaline derivatives are important from a therapeutic point of view since promising anti HIV agents (Patel et al., 2000), glucogen receptor antagonists (Guillon et al., 1998) and angiotens in receptor antagonists (Kim et al., 1993) possess this ring system. The title compound (I) was synthesized as part of our study of these ligands. Here we report the crystal structure of (I).

The structure of (I) is represented in Fig. 1. The bond lengths and angles are usual for this type of compound (Rong et al., 2006). The mean planes p1(C1 - C6) and p2 (N1,N2,C7 - C14) make a dihedral angle of 57.23 (1)°. The dihedral angles formed by phenyl ring(C8 –C13) and phenyl ring (C15 - C20) with p1 are 55.48 (1) and 64.80 (1)°, respectively. The dihedral angles between the benzene rings is 34.89 (1)°. The crystal packing (Fig. 2) is stabilized by van der Waals forces.

Experimental

A mixture of 1-(3-bromophenyl)-2-(4-bromophenyl)ethane-1,2-dione (5.77 g, 0.02 mol) and o-phenylene diamine (2.16 g, 0.02 mol) was stirred in refluxing ethanol (30 ml) for 5 h to afford the title compound (3.25 g, yield 74%). Single crystals suitable for X-ray measurements were obtained by recrystallization from THF at room temperature.

Refinement

H atoms were fixed geometrically and allowed to ride on their parent atoms, with N—H and C—H distances of 0.86 and 0.93–0.96 Å, respectively, and with Uiso=1.2–1.5Ueq of the parent atoms.

Figures

Fig. 1.
The molecular structure and atom-labeling scheme for (I), with displacement ellipsoids drawn at the 30% probability level.
Fig. 2.
The crystal packing of (I), viewed down the a axis.

Crystal data

C20H12Br2N2Z = 2
Mr = 440.14F000 = 432
Triclinic, P1Dx = 1.702 Mg m3
Hall symbol: -P 1Mo Kα radiation λ = 0.71073 Å
a = 6.0830 (12) ÅCell parameters from 25 reflections
b = 12.018 (2) Åθ = 4–14º
c = 12.323 (3) ŵ = 4.72 mm1
α = 105.47 (3)ºT = 293 (2) K
β = 91.89 (3)ºBlock, yellow
γ = 97.47 (3)º0.20 × 0.18 × 0.15 mm
V = 858.7 (3) Å3

Data collection

Enraf–Nonius CAD-4 diffractometerRint = 0.027
Radiation source: fine-focus sealed tubeθmax = 25.0º
Monochromator: graphiteθmin = 1.7º
T = 293(2) Kh = 0→7
ω scansk = −14→14
Absorption correction: ψ scan(North et al., 1968)l = −14→14
Tmin = 0.404, Tmax = 0.4923 standard reflections
3338 measured reflections every 100 reflections
2888 independent reflections intensity decay: none
1824 reflections with I > 2σ(I)

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.046H-atom parameters constrained
wR(F2) = 0.128  w = 1/[σ2(Fo2) + (0.0589P)2 + 0.7939P] where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max < 0.001
2888 reflectionsΔρmax = 0.56 e Å3
217 parametersΔρmin = −0.74 e Å3
Primary atom site location: structure-invariant direct methodsExtinction correction: none

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 (Å2)

xyzUiso*/Ueq
Br10.47031 (12)0.83130 (5)0.45247 (6)0.0741 (3)
Br2−0.24223 (11)0.30938 (6)−0.14438 (6)0.0753 (3)
N10.7857 (7)0.2921 (4)0.3229 (4)0.0493 (11)
N20.4951 (8)0.1176 (4)0.1656 (4)0.0542 (12)
C10.3718 (9)0.4705 (5)0.3533 (5)0.0526 (14)
H1B0.25640.41160.35320.063*
C20.3425 (9)0.5854 (5)0.3977 (5)0.0529 (14)
H2B0.21120.60410.42970.064*
C30.5130 (10)0.6720 (5)0.3936 (5)0.0522 (14)
C40.7127 (10)0.6469 (5)0.3496 (5)0.0589 (15)
H4A0.82550.70650.34800.071*
C50.7412 (9)0.5309 (5)0.3078 (5)0.0544 (14)
H5A0.87550.51290.27890.065*
C60.5720 (9)0.4407 (4)0.3082 (4)0.0461 (13)
C70.6106 (9)0.3173 (4)0.2700 (4)0.0462 (13)
C80.8169 (9)0.1783 (5)0.2990 (5)0.0493 (13)
C90.9999 (10)0.1469 (6)0.3534 (5)0.0652 (17)
H9A1.10070.20460.40250.078*
C101.0281 (12)0.0335 (6)0.3342 (6)0.0709 (18)
H10A1.14800.01300.36950.085*
C110.8729 (12)−0.0534 (6)0.2597 (6)0.0735 (19)
H11A0.8904−0.13140.24790.088*
C120.7000 (11)−0.0263 (5)0.2052 (6)0.0694 (18)
H12A0.6031−0.08520.15510.083*
C130.6657 (9)0.0901 (5)0.2238 (5)0.0505 (13)
C140.4677 (8)0.2285 (4)0.1856 (5)0.0472 (13)
C150.2918 (9)0.2540 (5)0.1121 (4)0.0477 (13)
C160.3189 (10)0.3520 (5)0.0707 (5)0.0584 (15)
H16A0.44550.40710.09400.070*
C170.1619 (10)0.3685 (5)−0.0041 (5)0.0611 (16)
H17A0.18360.4330−0.03260.073*
C18−0.0301 (9)0.2875 (5)−0.0366 (5)0.0545 (14)
C19−0.0638 (10)0.1897 (5)0.0024 (5)0.0576 (15)
H19A−0.19270.1362−0.02000.069*
C200.0981 (9)0.1728 (5)0.0755 (5)0.0516 (14)
H20A0.07830.10620.10100.062*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Br10.0889 (5)0.0564 (4)0.0746 (5)0.0182 (3)0.0012 (4)0.0107 (3)
Br20.0645 (4)0.0854 (5)0.0725 (5)0.0068 (3)−0.0241 (3)0.0212 (4)
N10.044 (3)0.053 (3)0.049 (3)0.009 (2)−0.002 (2)0.009 (2)
N20.048 (3)0.056 (3)0.057 (3)−0.001 (2)0.002 (2)0.016 (2)
C10.040 (3)0.056 (3)0.057 (4)0.001 (3)−0.004 (3)0.011 (3)
C20.039 (3)0.065 (4)0.052 (3)0.011 (3)−0.002 (3)0.010 (3)
C30.059 (4)0.051 (3)0.045 (3)0.010 (3)−0.006 (3)0.012 (3)
C40.050 (4)0.056 (3)0.066 (4)−0.004 (3)−0.001 (3)0.014 (3)
C50.039 (3)0.061 (3)0.061 (4)0.007 (3)0.002 (3)0.013 (3)
C60.041 (3)0.053 (3)0.041 (3)0.004 (2)−0.008 (2)0.010 (2)
C70.041 (3)0.053 (3)0.044 (3)0.004 (2)0.001 (2)0.013 (2)
C80.044 (3)0.058 (3)0.047 (3)0.009 (3)0.007 (3)0.014 (3)
C90.059 (4)0.073 (4)0.064 (4)0.022 (3)−0.010 (3)0.016 (3)
C100.076 (5)0.075 (4)0.072 (4)0.033 (4)0.001 (4)0.027 (4)
C110.084 (5)0.059 (4)0.087 (5)0.027 (4)0.018 (4)0.027 (4)
C120.065 (4)0.054 (3)0.087 (5)0.003 (3)0.000 (4)0.019 (3)
C130.047 (3)0.052 (3)0.054 (3)0.007 (3)0.010 (3)0.017 (3)
C140.037 (3)0.051 (3)0.050 (3)0.000 (2)0.004 (2)0.011 (3)
C150.042 (3)0.058 (3)0.041 (3)0.005 (2)0.001 (2)0.011 (3)
C160.051 (4)0.061 (4)0.057 (4)−0.008 (3)−0.010 (3)0.015 (3)
C170.063 (4)0.059 (3)0.061 (4)−0.002 (3)−0.009 (3)0.021 (3)
C180.043 (3)0.071 (4)0.045 (3)0.008 (3)−0.011 (3)0.011 (3)
C190.049 (3)0.070 (4)0.048 (3)−0.002 (3)−0.004 (3)0.013 (3)
C200.047 (3)0.057 (3)0.049 (3)0.002 (3)−0.002 (3)0.014 (3)

Geometric parameters (Å, °)

Br1—C31.913 (5)C9—C101.355 (8)
Br2—C181.913 (5)C9—H9A0.9300
N1—C71.339 (6)C10—C111.414 (9)
N1—C81.360 (7)C10—H10A0.9300
N2—C141.322 (7)C11—C121.350 (9)
N2—C131.367 (7)C11—H11A0.9300
C1—C21.380 (8)C12—C131.400 (8)
C1—C61.404 (8)C12—H12A0.9300
C1—H1B0.9300C14—C151.493 (7)
C2—C31.383 (8)C15—C161.397 (8)
C2—H2B0.9300C15—C201.405 (7)
C3—C41.383 (8)C16—C171.374 (8)
C4—C51.388 (8)C16—H16A0.9300
C4—H4A0.9300C17—C181.392 (8)
C5—C61.395 (7)C17—H17A0.9300
C5—H5A0.9300C18—C191.378 (8)
C6—C71.484 (7)C19—C201.384 (7)
C7—C141.443 (7)C19—H19A0.9300
C8—C131.412 (7)C20—H20A0.9300
C8—C91.424 (7)
C7—N1—C8117.5 (4)C11—C10—H10A120.4
C14—N2—C13118.5 (4)C12—C11—C10121.8 (6)
C2—C1—C6121.4 (5)C12—C11—H11A119.1
C2—C1—H1B119.3C10—C11—H11A119.1
C6—C1—H1B119.3C11—C12—C13120.4 (6)
C1—C2—C3118.5 (5)C11—C12—H12A119.8
C1—C2—H2B120.8C13—C12—H12A119.8
C3—C2—H2B120.8N2—C13—C12120.2 (5)
C2—C3—C4122.1 (5)N2—C13—C8120.9 (5)
C2—C3—Br1118.5 (4)C12—C13—C8118.8 (5)
C4—C3—Br1119.3 (4)N2—C14—C7120.4 (5)
C3—C4—C5118.6 (5)N2—C14—C15115.8 (4)
C3—C4—H4A120.7C7—C14—C15123.7 (5)
C5—C4—H4A120.7C16—C15—C20118.0 (5)
C4—C5—C6121.2 (5)C16—C15—C14122.4 (5)
C4—C5—H5A119.4C20—C15—C14119.4 (5)
C6—C5—H5A119.4C17—C16—C15121.2 (5)
C5—C6—C1118.1 (5)C17—C16—H16A119.4
C5—C6—C7120.4 (5)C15—C16—H16A119.4
C1—C6—C7121.3 (5)C16—C17—C18119.2 (5)
N1—C7—C14121.5 (5)C16—C17—H17A120.4
N1—C7—C6114.9 (4)C18—C17—H17A120.4
C14—C7—C6123.5 (5)C19—C18—C17121.5 (5)
N1—C8—C13120.9 (5)C19—C18—Br2119.8 (4)
N1—C8—C9119.7 (5)C17—C18—Br2118.6 (5)
C13—C8—C9119.4 (5)C18—C19—C20118.6 (5)
C10—C9—C8120.4 (6)C18—C19—H19A120.7
C10—C9—H9A119.8C20—C19—H19A120.7
C8—C9—H9A119.8C19—C20—C15121.5 (5)
C9—C10—C11119.1 (6)C19—C20—H20A119.3
C9—C10—H10A120.4C15—C20—H20A119.3
C6—C1—C2—C32.2 (8)C11—C12—C13—C81.0 (9)
C1—C2—C3—C4−1.9 (8)N1—C8—C13—N25.8 (8)
C1—C2—C3—Br1178.8 (4)C9—C8—C13—N2−176.5 (5)
C2—C3—C4—C50.4 (9)N1—C8—C13—C12−177.5 (5)
Br1—C3—C4—C5179.7 (4)C9—C8—C13—C120.2 (8)
C3—C4—C5—C60.9 (9)C13—N2—C14—C7−2.2 (8)
C4—C5—C6—C1−0.6 (8)C13—N2—C14—C15174.7 (5)
C4—C5—C6—C7−176.0 (5)N1—C7—C14—N26.1 (8)
C2—C1—C6—C5−1.0 (8)C6—C7—C14—N2−171.5 (5)
C2—C1—C6—C7174.4 (5)N1—C7—C14—C15−170.5 (5)
C8—N1—C7—C14−3.8 (8)C6—C7—C14—C1511.9 (8)
C8—N1—C7—C6174.0 (5)N2—C14—C15—C16−140.4 (6)
C5—C6—C7—N154.7 (7)C7—C14—C15—C1636.3 (8)
C1—C6—C7—N1−120.5 (6)N2—C14—C15—C2034.6 (7)
C5—C6—C7—C14−127.6 (6)C7—C14—C15—C20−148.6 (6)
C1—C6—C7—C1457.2 (7)C20—C15—C16—C17−0.3 (9)
C7—N1—C8—C13−1.9 (8)C14—C15—C16—C17174.8 (5)
C7—N1—C8—C9−179.6 (5)C15—C16—C17—C181.7 (9)
N1—C8—C9—C10177.2 (6)C16—C17—C18—C19−1.6 (9)
C13—C8—C9—C10−0.5 (9)C16—C17—C18—Br2−178.0 (5)
C8—C9—C10—C11−0.3 (10)C17—C18—C19—C200.1 (9)
C9—C10—C11—C121.5 (11)Br2—C18—C19—C20176.5 (4)
C10—C11—C12—C13−1.9 (11)C18—C19—C20—C151.3 (9)
C14—N2—C13—C12179.9 (6)C16—C15—C20—C19−1.2 (8)
C14—N2—C13—C8−3.5 (8)C14—C15—C20—C19−176.5 (5)
C11—C12—C13—N2177.7 (6)

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HG2324).

References

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Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography