2-Bromo-1-[1-(4-bromophenyl)-5-methyl-1H-1,2,3-triazol-4-yl]ethanone

The asymmetric unit of the title compound, C11H9Br2N3O, contains two crystallographically independent molecules with similar geometries; the Br—C—C=O torsion angles are 1.2 (4) and −2.8 (4)°, and the benzene and triazole rings are inclined o one another by 51.90 (16) and 51.88 (16)°. The two molecules are related by a pseudo-screw 21 axis directed along [100]. In the crystal, molecules are linked into a three-dimensional network by weak C—H⋯O and C—H⋯N hydrogen bonds and secondary Br⋯Br [3.5991 (8) and 3.6503 (9) Å] interactions.

The title compound (I) crystallizes in the non-centrosymmetric monoclinic space group Pn with two crystallographically independent molecules in the asymmetric unit ( Figure 2). The two crystallographically independent molecules are related by pseudo-screw axis 2 1 directed in [100] and, consequently, have very similar geometries ( Figure   3). The position of the pseudo-screw axis 2 1 with the approximate coordinates of (x, 0.75, 0.55) is shifted relative to the crystallographic position of (x, 0.75, 0.75) by ca. 0.20 Å towards the c axis, apparently, due to the formation of the more dense crystal packing as well as different non-valent intermolecular interactions.
The bond lengths and angles within the molecules of I are in a good agreement with those found in the related compounds (Danence et al. 2011;Zeghada et al. 2011;Abdel-Wahab, Abdel-Latif et al. 2013;Abdel-Wahab, Mohamed et al. 2013). The 2-bromo-1-ethanone substituent in the molecules of I has a significantly flattened conformation (the Br-C-C═O torsion angles are 1.2 (4) and -2.8 (4)° for the two independent molecules, respectively), with the carbonyl group directed toward the methyl substituent, and lies almost within the triazole plane (r.m.s. deviations are 0.037 and 0.023 Å for the two independent molecules, respectively) ( Figure 2). The bromo-benzene substituent is twisted by 52.30 (6) and 51.81 (6)° (for the two independent molecules, respectively) relative to this main plane of the molecule.

Refinement
The absolute configuration of I was objectively determined by the refinement of Flack parameter (3428 (99%) Friedel pairs measured) to 0.032 (7). The calculated Hooft parameter is equal to 0.023 (6).
All hydrogen atoms were placed in the calculated positions with C-H = 0.95 (aryl-H), 0.98 (methyl-H) and 0.99 (methylene-H) Å and refined in the riding model with fixed isotropic displacement parameters: U iso (H) = 1.2-1.5U eq (C).

Figure 2
Two independent molecules in the asymmetric unit of I. Displacement ellipsoids are presented at the 50% probability level. H atoms are depicted as small spheres of arbitrary radius.  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.72 e Å −3 Δρ min = −0.59 e Å −3 Absolute structure: Flack (1983), 3428 Friedel pairs Absolute structure parameter: 0.032 (7) Special details 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 F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.