Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102001683/da1213sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270102001683/da1213Isup2.hkl |
CCDC reference: 183037
2,4-Dibromoaniline (5.02 g, 20.0 mmol) was dissolved in glacial acetic acid (40 ml) and cooled below room temperature. A sodium nitrite solution (0.69 g, 10 mmol) in water (10 ml) was slowly added with continuous stirring. A yellow precipitate was observed. After complete addition of the above solution, the resulting mixture was neutralized with a 10% aqueous solution of NaHCO3. The yellow crude product was isolated by filtration and dried over P2O5 under vacuum. The product was recrystallized from a tetrahydrofuran/n-hexane mixture (1:1). Yellow plate-shaped crystals of (I) suitable for X-ray analysis were obtained by slow evaporation of the solvent mixture (yield 6.35 g, 95%; m.p. 428–429 K).
H atoms were treated as riding, with C—H = 0.93 Å, N—H = 0.86 Å and Uiso(H) = 1.2Ueq of the parent atom. Are these the correct restraints?
Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: SET4 in CAD-4 EXPRESS; data reduction: HELENA (Spek, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-32 (Farrugia, 1997) and PLATON (Spek, 1999); software used to prepare material for publication: SHELXL97 and ORTEP-32.
Fig. 1. The molecular structure of (I) with 70% probability displacement ellipsoids. H atoms are shown as small spheres of arbitrary radii. |
C12H7Br4N3 | F(000) = 960 |
Mr = 512.85 | Dx = 2.304 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71069 Å |
a = 10.701 (5) Å | Cell parameters from 25 reflections |
b = 9.949 (5) Å | θ = 6.2–15.1° |
c = 13.888 (5) Å | µ = 10.88 mm−1 |
β = 90° | T = 293 K |
V = 1478.6 (11) Å3 | Plate, yellow |
Z = 4 | 0.3 × 0.2 × 0.1 mm |
Enraf-Nonius CAD-4 diffractometer | 2045 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.037 |
Graphite monochromator | θmax = 26.0°, θmin = 3.2° |
θ/2θ scans | h = −13→13 |
Absorption correction: ψ-scan (Spek, 1990) | k = −12→1 |
Tmin = 0.115, Tmax = 0.337 | l = 0→17 |
3358 measured reflections | 3 standard reflections every 60 min |
2878 independent reflections | intensity decay: variation 0.5% |
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)] = 0.043 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.111 | H-atom parameters constrained |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0616P)2] where P = (Fo2 + 2Fc2)/3 |
2878 reflections | (Δ/σ)max = 0.001 |
172 parameters | Δρmax = 1.01 e Å−3 |
0 restraints | Δρmin = −1.00 e Å−3 |
C12H7Br4N3 | V = 1478.6 (11) Å3 |
Mr = 512.85 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 10.701 (5) Å | µ = 10.88 mm−1 |
b = 9.949 (5) Å | T = 293 K |
c = 13.888 (5) Å | 0.3 × 0.2 × 0.1 mm |
β = 90° |
Enraf-Nonius CAD-4 diffractometer | 2045 reflections with I > 2σ(I) |
Absorption correction: ψ-scan (Spek, 1990) | Rint = 0.037 |
Tmin = 0.115, Tmax = 0.337 | 3 standard reflections every 60 min |
3358 measured reflections | intensity decay: variation 0.5% |
2878 independent reflections |
R[F2 > 2σ(F2)] = 0.043 | 0 restraints |
wR(F2) = 0.111 | H-atom parameters constrained |
S = 1.02 | Δρmax = 1.01 e Å−3 |
2878 reflections | Δρmin = −1.00 e Å−3 |
172 parameters |
Geometry. Mean-plane data from final SHELXL refinement run:- Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) 6.0726 (0.0241) x - 6.8524 (0.0199) y - 6.2773 (0.0343) z = 4.4174 (0.0279) * -0.0005 (0.0045) C11 * 0.0006 (0.0046) C12 * 0.0037 (0.0046) C13 * -0.0081 (0.0047) C14 * 0.0080 (0.0048) C15 * -0.0038 (0.0047) C16 Rms deviation of fitted atoms = 0.0051 6.4038 (0.0317) x - 5.7985 (0.0621) y - 7.6461 (0.0976) z = 4.8162 (0.0239) Angle to previous plane (with approximate e.s.d.) = 8.48 (0.81) * 0.0000 (0.0000) N1 * 0.0000 (0.0000) N2 * 0.0000 (0.0000) N3 Rms deviation of fitted atoms = 0.0000 6.1338 (0.0228) x - 5.2575 (0.0219) y - 8.7085 (0.0292) z = 4.7291 (0.0091) Angle to previous plane (with approximate e.s.d.) = 5.57 (0.85) * 0.0034 (0.0043) C31 * -0.0096 (0.0046) C32 * 0.0080 (0.0046) C33 * -0.0004 (0.0046) C34 * -0.0057 (0.0047) C35 * 0.0043 (0.0046) C36 Rms deviation of fitted atoms = 0.0060 6.0530 (0.0142) x - 6.9156 (0.0124) y - 6.1730 (0.0103) z = 4.4060 (0.0171) Angle to previous plane (with approximate e.s.d.) = 14.21 (0.30) * 0.0191 (0.0030) Br1 * 0.0038 (0.0031) Br2 * -0.0086 (0.0050) C11 * -0.0166 (0.0054) C12 * -0.0094 (0.0052) C13 * -0.0076 (0.0056) C14 * 0.0179 (0.0056) C15 * 0.0015 (0.0048) C16 Rms deviation of fitted atoms = 0.0122 6.0142 (0.0138) x - 5.2511 (0.0065) y - 8.8552 (0.0169) z = 4.6711 (0.0050) Angle to previous plane (with approximate e.s.d.) = 14.68 (0.18) * -0.0273 (0.0030) Br3 * -0.0267 (0.0029) Br4 * 0.0019 (0.0048) C31 * 0.0105 (0.0054) C32 * 0.0385 (0.0053) C33 * 0.0190 (0.0053) C34 * -0.0079 (0.0053) C35 * -0.0080 (0.0047) C36 Rms deviation of fitted atoms = 0.0210 6.4038 (0.0317) x - 5.7985 (0.0621) y - 7.6461 (0.0976) z = 4.8162 (0.0239) Angle to previous plane (with approximate e.s.d.) = 6.26 (0.81) * 0.0000 (0.0000) N1 * 0.0000 (0.0000) N2 * 0.0000 (0.0000) N3 Rms deviation of fitted atoms = 0.0000 6.0530 (0.0142) x - 6.9156 (0.0124) y - 6.1730 (0.0103) z = 4.4060 (0.0171) Angle to previous plane (with approximate e.s.d.) = 9.06 (0.76) * 0.0191 (0.0030) Br1 * 0.0038 (0.0031) Br2 * -0.0086 (0.0050) C11 * -0.0166 (0.0054) C12 * -0.0094 (0.0052) C13 * -0.0076 (0.0056) C14 * 0.0179 (0.0056) C15 * 0.0015 (0.0048) C16 Rms deviation of fitted atoms = 0.0122 6.4038 (0.0317) x - 5.7985 (0.0621) y - 7.6461 (0.0976) z = 4.8162 (0.0239) Angle to previous plane (with approximate e.s.d.) = 9.06 (0.76) * 0.0000 (0.0000) N1 * 0.0000 (0.0000) N2 * 0.0000 (0.0000) N3 Rms deviation of fitted atoms = 0.0000 6.0142 (0.0138) x - 5.2511 (0.0065) y - 8.8552 (0.0169) z = 4.6711 (0.0050) Angle to previous plane (with approximate e.s.d.) = 6.26 (0.81) * -0.0273 (0.0030) Br3 * -0.0267 (0.0029) Br4 * 0.0019 (0.0048) C31 * 0.0105 (0.0054) C32 * 0.0385 (0.0053) C33 * 0.0190 (0.0053) C34 * -0.0079 (0.0053) C35 * -0.0080 (0.0047) C36 Rms deviation of fitted atoms = 0.0210 5.9745 (0.0251) x - 5.2365 (0.0268) y - 8.9172 (0.0161) z = 4.6544 (0.0135) Angle to previous plane (with approximate e.s.d.) = 0.34 (1/3) * 0.0308 (0.0012) H3 * -0.0302 (0.0016) N3 * -0.0014 (0.0041) C31 * 0.0152 (0.0038) C32 * -0.0144 (0.0018) Br3 Rms deviation of fitted atoms = 0.0215 6.4883 (0.0042) x - 5.8950 (0.0056) y - 7.3775 (0.0085) z = 4.8734 (0.0034) Angle to previous plane (with approximate e.s.d.) = 7.90 (0.31) * 0.4050 (0.0025) Br1 * -0.0972 (0.0028) Br2 * -0.0229 (0.0060) C11 * 0.1222 (0.0058) C12 * 0.1055 (0.0056) C13 * -0.0719 (0.0058) C14 * -0.2030 (0.0060) C15 * -0.1894 (0.0061) C16 * -0.0019 (0.0052) N1 * 0.0046 (0.0052) N2 * -0.0207 (0.0048) N3 * -0.0685 (0.0045) H3 * -0.3762 (0.0026) Br3 * 0.0694 (0.0028) Br4 * 0.0297 (0.0057) C31 * -0.1069 (0.0060) C32 * -0.0606 (0.0058) C33 * 0.0858 (0.0055) C34 * 0.2091 (0.0057) C35 * 0.1881 (0.0060) C36 Rms deviation of fitted atoms = 0.1637 |
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 | ||
Br3 | 0.47146 (7) | 0.04492 (7) | −0.23083 (5) | 0.0345 (2) | |
Br4 | 0.27792 (6) | −0.43594 (8) | −0.07722 (6) | 0.0377 (2) | |
Br1 | 1.02540 (6) | 0.31836 (8) | −0.06805 (5) | 0.0340 (2) | |
Br2 | 1.23075 (7) | 0.17883 (10) | 0.29211 (5) | 0.0455 (2) | |
N3 | 0.6699 (5) | 0.0053 (6) | −0.0729 (4) | 0.0258 (12) | |
H3 | 0.6679 | 0.0662 | −0.1168 | 0.031* | |
N2 | 0.7566 (5) | 0.0105 (6) | −0.0041 (4) | 0.0251 (12) | |
N1 | 0.8307 (5) | 0.1083 (5) | −0.0163 (4) | 0.0255 (12) | |
C31 | 0.5827 (5) | −0.0980 (6) | −0.0739 (4) | 0.0198 (13) | |
C32 | 0.4850 (6) | −0.0983 (7) | −0.1410 (4) | 0.0267 (14) | |
C33 | 0.3964 (5) | −0.1995 (7) | −0.1443 (5) | 0.0285 (16) | |
H33 | 0.3339 | −0.1986 | −0.1908 | 0.034* | |
C34 | 0.4023 (5) | −0.3008 (7) | −0.0780 (5) | 0.0260 (15) | |
C35 | 0.4975 (6) | −0.3041 (7) | −0.0084 (5) | 0.0288 (15) | |
H35 | 0.5005 | −0.3732 | 0.0367 | 0.035* | |
C36 | 0.5859 (6) | −0.2044 (7) | −0.0074 (4) | 0.0264 (15) | |
H36 | 0.6495 | −0.2073 | 0.0383 | 0.032* | |
C11 | 0.9217 (5) | 0.1192 (7) | 0.0579 (4) | 0.0231 (14) | |
C12 | 1.0164 (6) | 0.2143 (7) | 0.0455 (4) | 0.0250 (14) | |
C13 | 1.1087 (6) | 0.2326 (7) | 0.1144 (4) | 0.0281 (15) | |
H13 | 1.1720 | 0.2954 | 0.1054 | 0.034* | |
C14 | 1.1042 (6) | 0.1554 (8) | 0.1961 (4) | 0.0300 (16) | |
C15 | 1.0126 (6) | 0.0584 (8) | 0.2108 (5) | 0.0364 (18) | |
H15 | 1.0124 | 0.0052 | 0.2658 | 0.044* | |
C16 | 0.9225 (6) | 0.0441 (7) | 0.1411 (5) | 0.0279 (15) | |
H16 | 0.8594 | −0.0188 | 0.1505 | 0.034* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br3 | 0.0336 (4) | 0.0362 (4) | 0.0335 (4) | −0.0021 (3) | −0.0129 (3) | 0.0050 (3) |
Br4 | 0.0223 (3) | 0.0322 (4) | 0.0585 (5) | −0.0081 (3) | −0.0077 (3) | −0.0024 (4) |
Br1 | 0.0283 (4) | 0.0367 (4) | 0.0369 (4) | −0.0100 (3) | −0.0060 (3) | 0.0048 (3) |
Br2 | 0.0261 (4) | 0.0766 (6) | 0.0339 (4) | 0.0073 (4) | −0.0136 (3) | −0.0163 (4) |
N3 | 0.019 (3) | 0.024 (3) | 0.034 (3) | −0.003 (2) | −0.009 (2) | 0.003 (2) |
N2 | 0.020 (3) | 0.031 (3) | 0.024 (3) | 0.003 (3) | −0.006 (2) | −0.004 (2) |
N1 | 0.022 (3) | 0.024 (3) | 0.031 (3) | −0.002 (2) | −0.012 (2) | −0.005 (3) |
C31 | 0.014 (3) | 0.022 (3) | 0.023 (3) | −0.001 (3) | 0.004 (2) | −0.007 (3) |
C32 | 0.023 (3) | 0.031 (4) | 0.026 (3) | 0.006 (3) | −0.003 (3) | 0.000 (3) |
C33 | 0.011 (3) | 0.038 (4) | 0.036 (3) | −0.001 (3) | −0.008 (3) | −0.007 (3) |
C34 | 0.009 (3) | 0.031 (4) | 0.038 (3) | −0.001 (3) | 0.001 (3) | −0.009 (3) |
C35 | 0.021 (3) | 0.021 (3) | 0.044 (4) | 0.001 (3) | −0.001 (3) | 0.001 (3) |
C36 | 0.019 (3) | 0.032 (4) | 0.028 (3) | 0.000 (3) | −0.005 (3) | 0.001 (3) |
C11 | 0.013 (3) | 0.029 (4) | 0.027 (3) | 0.000 (3) | −0.001 (2) | −0.005 (3) |
C12 | 0.029 (3) | 0.022 (3) | 0.024 (3) | 0.002 (3) | −0.001 (3) | −0.008 (3) |
C13 | 0.016 (3) | 0.037 (4) | 0.031 (3) | 0.001 (3) | −0.001 (3) | −0.009 (3) |
C14 | 0.018 (3) | 0.047 (4) | 0.026 (3) | 0.001 (3) | −0.004 (3) | −0.016 (3) |
C15 | 0.030 (4) | 0.052 (5) | 0.027 (3) | 0.015 (4) | −0.003 (3) | 0.006 (4) |
C16 | 0.020 (3) | 0.028 (4) | 0.036 (3) | −0.003 (3) | 0.001 (3) | −0.002 (3) |
Br3—C32 | 1.900 (7) | C35—C36 | 1.371 (9) |
Br4—C34 | 1.892 (6) | C35—H35 | 0.9300 |
Br1—C12 | 1.890 (6) | C36—H36 | 0.9300 |
Br2—C14 | 1.913 (6) | C11—C16 | 1.376 (9) |
N3—N2 | 1.332 (7) | C11—C12 | 1.397 (9) |
N3—C31 | 1.388 (8) | C12—C13 | 1.386 (8) |
N3—H3 | 0.8600 | C13—C14 | 1.371 (9) |
N2—N1 | 1.267 (7) | C13—Br3i | 3.419 (6) |
N1—C11 | 1.422 (7) | C13—H13 | 0.9300 |
C31—C32 | 1.400 (8) | C14—C15 | 1.391 (10) |
C31—C36 | 1.405 (9) | C14—Br3i | 3.455 (7) |
C32—C33 | 1.384 (9) | C15—C16 | 1.373 (9) |
C33—C34 | 1.366 (9) | C15—H15 | 0.9300 |
C33—H33 | 0.9300 | C16—Br1ii | 3.788 (7) |
C34—C35 | 1.404 (9) | C16—H16 | 0.9300 |
N2—N3—C31 | 120.2 (5) | C12—C11—N1 | 117.3 (6) |
N2—N3—H3 | 119.9 | C13—C12—C11 | 121.4 (6) |
C31—N3—H3 | 119.9 | C13—C12—Br1 | 117.8 (5) |
N1—N2—N3 | 111.6 (5) | C11—C12—Br1 | 120.8 (4) |
N2—N1—C11 | 112.9 (5) | C14—C13—C12 | 118.1 (6) |
N3—C31—C32 | 120.7 (6) | C14—C13—Br3i | 80.0 (4) |
N3—C31—C36 | 122.4 (5) | C12—C13—Br3i | 102.3 (4) |
C32—C31—C36 | 116.9 (6) | C14—C13—H13 | 120.9 |
C33—C32—C31 | 122.3 (6) | C12—C13—H13 | 120.9 |
C33—C32—Br3 | 118.2 (4) | Br3i—C13—H13 | 87.8 |
C31—C32—Br3 | 119.5 (5) | C13—C14—C15 | 122.4 (6) |
C34—C33—C32 | 118.9 (5) | C13—C14—Br2 | 118.9 (5) |
C34—C33—H33 | 120.5 | C15—C14—Br2 | 118.7 (5) |
C32—C33—H33 | 120.5 | C13—C14—Br3i | 77.0 (4) |
C33—C34—C35 | 121.0 (6) | C15—C14—Br3i | 105.4 (4) |
C33—C34—Br4 | 119.8 (4) | Br2—C14—Br3i | 88.9 (2) |
C35—C34—Br4 | 119.3 (5) | C16—C15—C14 | 117.6 (6) |
C36—C35—C34 | 119.3 (6) | C16—C15—H15 | 121.2 |
C36—C35—H35 | 120.3 | C14—C15—H15 | 121.2 |
C34—C35—H35 | 120.3 | C15—C16—C11 | 122.6 (6) |
C35—C36—C31 | 121.5 (6) | C15—C16—Br1ii | 100.6 (5) |
C35—C36—H36 | 119.2 | C11—C16—Br1ii | 107.0 (4) |
C31—C36—H36 | 119.2 | C15—C16—H16 | 118.7 |
C16—C11—C12 | 117.9 (5) | C11—C16—H16 | 118.7 |
C16—C11—N1 | 124.8 (6) | Br1ii—C16—H16 | 60.2 |
C31—N3—N2—N1 | 177.7 (5) | C16—C11—C12—Br1 | 178.2 (5) |
N3—N2—N1—C11 | 177.9 (5) | N1—C11—C12—Br1 | −2.4 (8) |
N2—N3—C31—C32 | 174.7 (6) | C11—C12—C13—C14 | −0.6 (10) |
N2—N3—C31—C36 | −3.9 (9) | Br1—C12—C13—C14 | −178.7 (5) |
N3—C31—C32—C33 | 179.9 (6) | C11—C12—C13—Br3i | −85.7 (6) |
C36—C31—C32—C33 | −1.4 (9) | Br1—C12—C13—Br3i | 96.2 (4) |
N3—C31—C32—Br3 | −0.4 (8) | C12—C13—C14—C15 | 1.5 (10) |
C36—C31—C32—Br3 | 178.2 (5) | Br3i—C13—C14—C15 | 100.1 (6) |
C31—C32—C33—C34 | 1.9 (10) | C12—C13—C14—Br2 | 180.0 (5) |
Br3—C32—C33—C34 | −177.8 (5) | Br3i—C13—C14—Br2 | −81.4 (4) |
C32—C33—C34—C35 | −1.0 (10) | C12—C13—C14—Br3i | −98.6 (6) |
C32—C33—C34—Br4 | 177.1 (5) | C13—C14—C15—C16 | −1.9 (10) |
C33—C34—C35—C36 | −0.3 (10) | Br2—C14—C15—C16 | 179.6 (5) |
Br4—C34—C35—C36 | −178.4 (5) | Br3i—C14—C15—C16 | 82.3 (6) |
C34—C35—C36—C31 | 0.8 (10) | C14—C15—C16—C11 | 1.5 (10) |
N3—C31—C36—C35 | 178.7 (6) | C14—C15—C16—Br1ii | 119.7 (6) |
C32—C31—C36—C35 | 0.1 (9) | C12—C11—C16—C15 | −0.7 (10) |
N2—N1—C11—C16 | −7.8 (9) | N1—C11—C16—C15 | −180.0 (6) |
N2—N1—C11—C12 | 172.9 (6) | C12—C11—C16—Br1ii | −115.8 (5) |
C16—C11—C12—C13 | 0.3 (10) | N1—C11—C16—Br1ii | 64.9 (7) |
N1—C11—C12—C13 | 179.6 (6) | N2—N3—C31—C32 | 174.7 (6) |
Symmetry codes: (i) x+1/2, −y+1/2, z+1/2; (ii) −x+2, −y, −z. |
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3···Br2iii | 0.86 | 2.91 | 3.717 (6) | 156 |
N3—H3···Br3 | 0.86 | 2.64 | 3.076 (5) | 113 |
Symmetry code: (iii) x−1/2, −y+1/2, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | C12H7Br4N3 |
Mr | 512.85 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 10.701 (5), 9.949 (5), 13.888 (5) |
β (°) | 90, 90, 90 |
V (Å3) | 1478.6 (11) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 10.88 |
Crystal size (mm) | 0.3 × 0.2 × 0.1 |
Data collection | |
Diffractometer | Enraf-Nonius CAD-4 diffractometer |
Absorption correction | ψ-scan (Spek, 1990) |
Tmin, Tmax | 0.115, 0.337 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3358, 2878, 2045 |
Rint | 0.037 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.043, 0.111, 1.02 |
No. of reflections | 2878 |
No. of parameters | 172 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.01, −1.00 |
Computer programs: CAD-4 EXPRESS (Enraf-Nonius, 1994), SET4 in CAD-4 EXPRESS, HELENA (Spek, 1996), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-32 (Farrugia, 1997) and PLATON (Spek, 1999), SHELXL97 and ORTEP-32.
Br3—C32 | 1.900 (7) | N3—H3 | 0.8600 |
Br4—C34 | 1.892 (6) | N2—N1 | 1.267 (7) |
Br1—C12 | 1.890 (6) | N1—C11 | 1.422 (7) |
Br2—C14 | 1.913 (6) | C13—Br3i | 3.419 (6) |
N3—N2 | 1.332 (7) | C14—Br3i | 3.455 (7) |
N3—C31 | 1.388 (8) | C16—Br1ii | 3.788 (7) |
N2—N3—C31 | 120.2 (5) | C35—C34—Br4 | 119.3 (5) |
N1—N2—N3 | 111.6 (5) | C12—C11—N1 | 117.3 (6) |
N2—N1—C11 | 112.9 (5) | C11—C12—Br1 | 120.8 (4) |
N3—C31—C32 | 120.7 (6) | C13—C14—Br2 | 118.9 (5) |
C31—C32—Br3 | 119.5 (5) | ||
C31—N3—N2—N1 | 177.7 (5) | N2—N1—C11—C16 | −7.8 (9) |
N3—N2—N1—C11 | 177.9 (5) | N2—N1—C11—C12 | 172.9 (6) |
N2—N3—C31—C32 | 174.7 (6) | N1—C11—C12—Br1 | −2.4 (8) |
N2—N3—C31—C36 | −3.9 (9) | N2—N3—C31—C32 | 174.7 (6) |
N3—C31—C32—Br3 | −0.4 (8) |
Symmetry codes: (i) x+1/2, −y+1/2, z+1/2; (ii) −x+2, −y, −z. |
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3···Br2iii | 0.86 | 2.91 | 3.717 (6) | 156 |
N3—H3···Br3 | 0.86 | 2.64 | 3.076 (5) | 113 |
Symmetry code: (iii) x−1/2, −y+1/2, z−1/2. |
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Free 1,3-disubstituted triazenes, RN═N—N(H)R, are generally believed to adopt a trans stereochemistry about the N═N double-bond (Moore & Robinson, 1986). This arrangement has been confirmed for numerous examples characterized by X-ray diffraction. Here, we report the synthesis and structural characterization of the title compound, (I), a symmetric disubstituted 1,3-diaryltriazene having polarizable halogen atoms on the terminal aryl rings. These halogen atoms make contacts with the H atom of the protonated triazenide chain. \sch
The molecular structure of (I) is shown in Fig. 1 and selected geometric parameters are given in Table 1. Deviations from the normal N—N and Car—N bond lengths suggest delocalization of the π electrons on the triazene group extended to the terminal aryl substituents. N1═N2 [1.267 (7) Å] is longer than the characteristic value for a double bond (1.24 Å), whereas N2—N3 [1.332 (7) Å] is shorter than the characteristic value for a single bond (1.44 Å) (International Tables for X-Ray Crystallography, 1985, Vol. III, p. 270). Both N1—C11 [1.422 (7) Å] and N3—C31 [1.388 (8) Å] are shorter than expected for a Car—N single bond. These values are in good agreement with those found in related compounds (Zhang et al., 1999; Walton et al., 1991).
The terminal 2,4-dibromophenyl substituents make an interplanar angle of 14.7 (2)°, indicating the lack of planarity of the whole molecule. Due to the weak intramolecular N3—H3···Br3 interaction [N3···Br3 3.076 (5) Å], the related 2,4-dibromophenyl substituent is nearly coplanar with the N1═ N2—N3 group [N2—N3—C31—C32 174.7 (6)°].
The crystal structure of (I) reveals that diagonal glide-plane-related molecules are ordered as polymer chains by weak N3—H3···Br2 intermolecular interactions [N3···Br2i 3.717 (6) Å; symmetry code: (i) x + 1/2, 1/2 - y, z - 1/2]. These polymer chains are stacked along the [100] direction, and are associated in pairs by an inversion centre. Weak interactions between these pairs can be recognized by intermolecular C···Br contacts [C16···Br1ii 3.788 (7) Å; symmetry code: (ii) 2 - x, 1 - y, 2 - z]. On the other hand, weak intermolecular C···Br contacts [C13···Br3iii 3.419 (6) Å and C14···Br3iii 3.455 (7) Å; symmetry code: (iii) x - 1/2, 1/2 - y, 1/2 + z] observed along the individual polymer chains hinder the coplanarity of the C11—C16 aryl group with the plane defined by the N1═N2—N3 group [interplanar angle 9.1 (8)°].