Salhin Abdussalam, Abdul Razak Norfarhah, Rahman I A
School of Chemical Sciences, Universiti Sains Malaysia, USM, Penang, 11800, Malaysia.
Acta Crystallogr Sect E Struct Rep Online. 2009 May 7;65(Pt 6):o1221-2. doi: 10.1107/S1600536809016225.
The title compound, C(14)H(11)BrN(4)O(4), comprises two crystallographically independent mol-ecules (A and B) in the asymmetric unit. In mol-ecule B, intra-molecular bifurcated N-H⋯O and N-H⋯Br hydrogen bonds and in mol-ecule A, an intra-molecular N-H⋯O hydrogen bond generate S(6) ring motifs. The dihedral angle between the phenyl and benzene rings is 5.44 (6) in mol-ecule A and 7.63 (6)° in mol-ecule B. The ortho- and meta-nitro substituents make dihedral angles of 6.67 (15) and 2.26 (15)° to the attached benzene ring in mol-ecule A and 6.37 (17) and 5.81 (16)° in mol-ecule B. The Br atom in mol-ecule B is disordered over two positions with a refined site-occupancy ratio of 0.61 (3):0.39 (3). Inter-esting features of the crystal structure are the short Br⋯N [3.257 (3)-3.294 (4) Å], Br⋯O [3.279 (3)-3.307 (4) Å] and O⋯O [2.9319 (16)-2.9995 (16) Å] contacts, which are shorter than the sum of the van der Waals radii of these atoms. The crystal structure is further stabilized by inter-molecular C-H⋯O and π-π inter-actions [centroid-centroid distances = 3.6643 (8)-3.8514 (8) Å].
标题化合物C(14)H(11)BrN(4)O(4)在不对称单元中包含两个晶体学独立的分子（A和B）。在分子B中，分子内的分叉N-H⋯O和N-H⋯Br氢键以及在分子A中，分子内的N-H⋯O氢键形成了S(6)环模式。分子A中苯环和苯环之间的二面角为5.44 (6)°，分子B中为7.63 (6)°。邻位和间位硝基取代基与分子A中相连苯环的二面角分别为6.67 (15)°和2.26 (15)°，分子B中为6.37 (17)°和5.81 (16)°。分子B中的Br原子在两个位置上无序，精修的位点占有率比为0.61 (3):0.39 (3)。晶体结构的有趣特征是短的Br⋯N [3.257 (3)-3.294 (4) Å]、Br⋯O [3.279 (3)-3.307 (4) Å]和O⋯O [2.9319 (16)-2.9995 (16) Å]接触，这些接触比这些原子的范德华半径之和短。晶体结构通过分子间的C-H⋯O和π-π相互作用[质心-质心距离 = 3.6643 (8)-3.8514 (8) Å]进一步稳定。
