Acta Cryst. (2012). E68, o2348 [ doi:10.1107/S1600536812029832 ]
The asymmetric unit of the title compound, C16H12Br4N2O2, comprises half of a potential tetradentate Schiff base ligand. The whole molecule is generated by an inversion center located in the middle of the C-C bond of the ethylene segment. There are intramolecular O-HN hydrogen bonds making S(6) ring motifs. In the crystal, no significant intermolecular interactions are observed.
The title compound was synthesized by adding 3,5-dibromosalicylaldehyde (2 mmol) to a solution of ethylenediamine (1 mmol) in ethanol (30 ml). The mixture was refluxed with stirring for 30 min. The resultant solution was filtered. Yellow single crystals of the title compound suitable for X-ray structure determination were recrystallized from ethanol by slow evaporation of the solvents at room temperature over several days.
The O-bound H atom was located in a difference Fourier map and constrained to refine on the parent O atom with Uiso(H) = 1.5Ueq(O). The C-bound H-atoms were included in calculated positions and treated as riding atoms: C—H = 0.93 and 0.97 Å for CH and CH2 H-atoms, respectively, with Uiso(H) = 1.2Ueq(C).
Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); 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) and PLATON (Spek, 2009).
C16H12Br4N2O2 | F(000) = 556 |
Mr = 583.92 | Dx = 2.150 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 1563 reflections |
a = 12.723 (3) Å | θ = 2.5–27.4° |
b = 10.291 (2) Å | µ = 8.93 mm−1 |
c = 6.9428 (18) Å | T = 291 K |
β = 97.046 (15)° | Block, pale-yellow |
V = 902.2 (4) Å3 | 0.21 × 0.14 × 0.08 mm |
Z = 2 |
Bruker SMART APEXII CCD area-detector diffractometer | 1981 independent reflections |
Radiation source: fine-focus sealed tube | 1086 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.075 |
φ and ω scans | θmax = 27.1°, θmin = 1.6° |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | h = −16→13 |
Tmin = 0.256, Tmax = 0.535 | k = −13→12 |
6730 measured reflections | l = −8→8 |
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)] = 0.069 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.202 | H-atom parameters constrained |
S = 0.98 | w = 1/[σ2(Fo2) + (0.1116P)2] where P = (Fo2 + 2Fc2)/3 |
1981 reflections | (Δ/σ)max < 0.001 |
109 parameters | Δρmax = 1.40 e Å−3 |
0 restraints | Δρmin = −0.90 e Å−3 |
C16H12Br4N2O2 | V = 902.2 (4) Å3 |
Mr = 583.92 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 12.723 (3) Å | µ = 8.93 mm−1 |
b = 10.291 (2) Å | T = 291 K |
c = 6.9428 (18) Å | 0.21 × 0.14 × 0.08 mm |
β = 97.046 (15)° |
Bruker SMART APEXII CCD area-detector diffractometer | 1981 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | 1086 reflections with I > 2σ(I) |
Tmin = 0.256, Tmax = 0.535 | Rint = 0.075 |
6730 measured reflections | θmax = 27.1° |
R[F2 > 2σ(F2)] = 0.069 | H-atom parameters constrained |
wR(F2) = 0.202 | Δρmax = 1.40 e Å−3 |
S = 0.98 | Δρmin = −0.90 e Å−3 |
1981 reflections | Absolute structure: ? |
109 parameters | Flack parameter: ? |
0 restraints | Rogers parameter: ? |
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. |
x | y | z | Uiso*/Ueq | ||
Br1 | 0.30804 (8) | 0.64680 (8) | 0.49803 (17) | 0.0684 (4) | |
Br2 | −0.05455 (7) | 0.36429 (9) | 0.18237 (15) | 0.0615 (4) | |
O1 | 0.4014 (4) | 0.3794 (5) | 0.5301 (8) | 0.0514 (14) | |
H1 | 0.4198 | 0.3042 | 0.5527 | 0.077* | |
N1 | 0.3995 (5) | 0.1295 (5) | 0.5201 (10) | 0.0456 (17) | |
C1 | 0.3005 (5) | 0.3720 (7) | 0.4544 (11) | 0.0373 (17) | |
C2 | 0.2407 (6) | 0.4862 (7) | 0.4249 (11) | 0.0408 (18) | |
C3 | 0.1366 (6) | 0.4860 (7) | 0.3445 (11) | 0.0443 (19) | |
H3A | 0.0991 | 0.5633 | 0.3236 | 0.053* | |
C4 | 0.0901 (6) | 0.3697 (7) | 0.2964 (12) | 0.0417 (18) | |
C5 | 0.1429 (5) | 0.2529 (7) | 0.3262 (10) | 0.0399 (18) | |
H5A | 0.1087 | 0.1748 | 0.2926 | 0.048* | |
C6 | 0.2490 (6) | 0.2542 (7) | 0.4080 (11) | 0.0398 (18) | |
C7 | 0.3031 (6) | 0.1305 (8) | 0.4442 (11) | 0.044 (2) | |
H7A | 0.2677 | 0.0529 | 0.4124 | 0.053* | |
C8 | 0.4522 (6) | 0.0026 (8) | 0.5551 (13) | 0.053 (2) | |
H8A | 0.4034 | −0.0668 | 0.5118 | 0.063* | |
H8B | 0.4743 | −0.0087 | 0.6928 | 0.063* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.0479 (6) | 0.0445 (6) | 0.1087 (9) | −0.0044 (4) | −0.0059 (5) | −0.0085 (5) |
Br2 | 0.0317 (5) | 0.0595 (7) | 0.0885 (8) | 0.0053 (3) | −0.0116 (4) | −0.0005 (5) |
O1 | 0.032 (3) | 0.051 (3) | 0.067 (4) | 0.002 (2) | −0.009 (3) | −0.001 (3) |
N1 | 0.040 (4) | 0.041 (4) | 0.055 (4) | 0.014 (3) | 0.006 (3) | 0.003 (3) |
C1 | 0.022 (4) | 0.046 (5) | 0.043 (4) | 0.004 (3) | 0.004 (3) | −0.001 (3) |
C2 | 0.032 (4) | 0.043 (4) | 0.048 (5) | 0.002 (3) | 0.002 (3) | −0.004 (4) |
C3 | 0.035 (4) | 0.040 (5) | 0.055 (5) | 0.011 (3) | −0.003 (3) | −0.001 (4) |
C4 | 0.025 (4) | 0.046 (5) | 0.054 (5) | 0.003 (3) | 0.002 (3) | −0.001 (4) |
C5 | 0.033 (4) | 0.046 (5) | 0.040 (4) | −0.004 (3) | 0.000 (3) | 0.004 (3) |
C6 | 0.038 (4) | 0.041 (4) | 0.040 (4) | 0.007 (3) | 0.003 (3) | −0.001 (3) |
C7 | 0.038 (5) | 0.052 (5) | 0.042 (4) | 0.008 (3) | 0.003 (3) | −0.003 (4) |
C8 | 0.031 (4) | 0.052 (5) | 0.074 (6) | 0.017 (4) | 0.004 (4) | 0.013 (4) |
Br1—C2 | 1.902 (7) | C3—H3A | 0.9300 |
Br2—C4 | 1.913 (8) | C4—C5 | 1.381 (10) |
O1—C1 | 1.328 (9) | C5—C6 | 1.399 (10) |
O1—H1 | 0.8184 | C5—H5A | 0.9300 |
N1—C7 | 1.274 (10) | C6—C7 | 1.455 (10) |
N1—C8 | 1.474 (9) | C7—H7A | 0.9300 |
C1—C6 | 1.396 (10) | C8—C8i | 1.515 (15) |
C1—C2 | 1.401 (10) | C8—H8A | 0.9700 |
C2—C3 | 1.372 (10) | C8—H8B | 0.9700 |
C3—C4 | 1.359 (10) | ||
C1—O1—H1 | 105.2 | C4—C5—H5A | 120.7 |
C7—N1—C8 | 118.1 (7) | C6—C5—H5A | 120.7 |
O1—C1—C6 | 123.0 (6) | C1—C6—C5 | 120.3 (7) |
O1—C1—C2 | 119.4 (6) | C1—C6—C7 | 121.4 (7) |
C6—C1—C2 | 117.6 (7) | C5—C6—C7 | 118.3 (7) |
C3—C2—C1 | 122.5 (7) | N1—C7—C6 | 119.3 (7) |
C3—C2—Br1 | 119.3 (5) | N1—C7—H7A | 120.4 |
C1—C2—Br1 | 118.1 (6) | C6—C7—H7A | 120.4 |
C4—C3—C2 | 118.1 (7) | N1—C8—C8i | 109.0 (8) |
C4—C3—H3A | 120.9 | N1—C8—H8A | 109.9 |
C2—C3—H3A | 120.9 | C8i—C8—H8A | 109.9 |
C3—C4—C5 | 122.7 (7) | N1—C8—H8B | 109.9 |
C3—C4—Br2 | 119.7 (5) | C8i—C8—H8B | 109.9 |
C5—C4—Br2 | 117.5 (6) | H8A—C8—H8B | 108.3 |
C4—C5—C6 | 118.7 (7) | ||
O1—C1—C2—C3 | 179.0 (7) | O1—C1—C6—C5 | −179.2 (7) |
C6—C1—C2—C3 | −3.2 (12) | C2—C1—C6—C5 | 3.1 (11) |
O1—C1—C2—Br1 | −0.6 (10) | O1—C1—C6—C7 | 1.3 (12) |
C6—C1—C2—Br1 | 177.2 (5) | C2—C1—C6—C7 | −176.4 (7) |
C1—C2—C3—C4 | 1.5 (12) | C4—C5—C6—C1 | −1.3 (11) |
Br1—C2—C3—C4 | −179.0 (6) | C4—C5—C6—C7 | 178.2 (7) |
C2—C3—C4—C5 | 0.4 (13) | C8—N1—C7—C6 | 180.0 (7) |
C2—C3—C4—Br2 | −179.6 (6) | C1—C6—C7—N1 | 0.1 (12) |
C3—C4—C5—C6 | −0.5 (12) | C5—C6—C7—N1 | −179.5 (7) |
Br2—C4—C5—C6 | 179.5 (6) | C7—N1—C8—C8i | 121.0 (10) |
Symmetry code: (i) −x+1, −y, −z+1. |
HK and AAA thank PNU for financial support. MNT thanks GC University of Sargodha, Pakistan, for research facilities.
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Kargar, H., Kia, R., Pahlavani, E. & Tahir, M. N. (2011). Acta Cryst. E67, o614.
Kia, R., Kargar, H., Adabi Ardakani, A. & Tahir, M. N. (2012). Acta Cryst. E68, o2242–o2243.
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Spek, A. L. (2009). Acta Cryst. D65, 148–155.
In continuation of our work on the crystal structure analyses of Schiff base ligands (Kargar et al., (2011); Kia et al., (2010), we synthesized the title compound and report herein on its crystal structure.
The asymmetric unit of the title compound, Fig. 1, comprises half of a potentially tetradentate Schiff base ligand. The molecule is located about an inversion center, located in the middle of the C8—C8A bond of the ethylene segment. The bond lengths (Allen et al., 1987) and angles are within the normal ranges and are comparable to those reported for a similar compound (Kia et al., 2012). The intramolecular O—H···N hydrogen bonds (Table 1) make S(6) ring motifs (Bernstein et al., 1995).
In the crystal, there are no significant intermolecular interactions present.