1-Allyl-5-nitro-1H-benzimidazol-2(3H)-one

The benzimidazolone residue in the title molecule, C10H9N3O3, is almost planar, with the largest deviation from the mean plane being 0.016 (2) Å for the C atom linked to the nitro group. This plane is nearly perpendicular to the 1-allyl chain as indicated by the C—N—C—C torsion angle of 90.9 (3)°. The fused-ring system makes a dihedral angle of 5.6 (3)° with the nitro group, leading to a synperiplanar conformation. In the crystal, zigzag supramolecular chains are formed along the a axis by N—H⋯O hydrogen bonds.

As a continuation of our research work devoted to the development of substituted benzimidazol-2-one derivatives (Ouzidan et al., 2011a(Ouzidan et al., , 2011b, we report in this paper the synthesis of a new benzimidazol-2-one derivative by action of allyl-bromide with 5-nitro-1H-benzo[d]imidazol-2(3H)one using similar conditions as employed in earlier studies.
The two fused five-and six-membered rings in the molecule of the title compound, C 10 H 9 N 3 O 3 , are approximately planar, the largest deviation from the mean plane being -0.016 (2) A° at C1 (Fig. 1). The dihedral angle between the benzimidazolone mean plane and the 1-allyl chain (C4-N3-C8-C9) is 90.9 (3)°. The fused-ring system makes a dihedral angle of 5.6 (3)° with the nitro group, leading to a syn-periplanar conformation. In the crystal, each molecule is linked to symmetry equivalents by N2-H2n···O3 hydrogen bonds, Table 2, forming a supramolecular zigzag chain running along the a axis, as shown in Fig. 2.

Refinement
H atoms were located in a difference map and treated as riding with N-H = 0.86 Å, C-H = 0.93 Å (aromatic) and C-H = 0.97 Å (methylene), and with U iso (H) = 1.2 U eq (parent atom). Disorder is noted in the allyl group as evidence by the shorter than normal C9═C10 bond length of 1.177 (5) Å. Attempts to resolve this disorder for this room temperature data set were not successful.

Computing details
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); 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, 2012); software used to prepare material for publication: PLATON (Spek, 2009) and publCIF (Westrip, 2010).   Molecule and its symmetry partner linked by N2-H2n···O3 hydrogen bonds. Symmetry codes: (i) 1/2 -x, 1 -y, 1/2 + z. 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 > σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq C1 0.1801 (