5-Amino-4-bromo-2,3-dihydro-1H-inden-1-one

In the title compound, C9H8BrNO, the non-H-atom framework is essentially planar, with a maximum deviation of 0.087 (3) Å. In the crystal, molecules are interconnected into a three-dimensional network by C—H⋯O and N—H⋯O hydrogen bonds. In addition, C—H⋯π interactions and a π–π stacking interaction, with a centroid–centroid distance of 3.5535 (19) Å, are also observed.

In the title compound, C 9 H 8 BrNO, the non-H-atom framework is essentially planar, with a maximum deviation of 0.087 (3) Å . In the crystal, molecules are interconnected into a three-dimensional network by C-HÁ Á ÁO and N-HÁ Á ÁO hydrogen bonds. In addition, C-HÁ Á Á interactions and a stacking interaction, with a centroid-centroid distance of 3.5535 (19) Å , are also observed.
As shown in Fig. 1, the molecule of (I), except H atoms, is essentially planar with a maximum deviation of -0.087 (3) Å for O1 atom. Bond lengths and angles observed in (I) are normal (Allen et al., 1987).
The crystal packing is stabilized by intermolecular C-H···O and N-H···O hydrogen bonds (Table 1, Fig. 2) forming a three-dimensional network. In addition, π-π stacking interactions [centroid-centroid distance = 3.5535 (19) Å] between the centroids of the C1-C6 benzene rings of the neighbouring molecules stacking interactions are also observed. C-H···π interactions further help in stabilizing the supramolecular structure (Table 1).

Refinement
The H atoms of the amino group was located in a difference Fourier map and were isotropically refined with the distance restraints (N-H = 0.86 (2) Å and H···H = 1.30 (2) Å). C-bound H-atoms were positioned geometrically and refined using a riding model [C-H = 0.93 and 0.97 Å, and U iso (H) = 1.2U eq (C)]. The highest residual electron density peak and the deepest hole are located 1.03 Å and 0.89 Å from Br1, respectively.

Computing details
Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1999); software used to prepare material for publication: WinGX (Farrugia, 1997) and PLATON (Spek, 2009     The packing and hydrogen bonding of (I), viewing down the b axis. H atoms not involved in hydrogen bonding have been omitted. Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses 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 observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs 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.