(Z)-1-Chloro-1-[2-(2-nitrophenyl)hydrazinylidene]propan-2-one

The title molecule, C9H8ClN3O3, lies on a mirror plane. Intramolecular N—H⋯O and N—H⋯Cl hydrogen bonds occur. One of the nitro O atoms is disordered (site occupancy ratio = 0.40:0.10).


Related literature
For details of the synthesis and for the importance of hydrazonoyl halides in organic synthesis and their biological activity and metabolism, see: Awadallah et al. (2006Awadallah et al. ( , 2008 109 parameters H-atom parameters constrained Á max = 0.58 e Å À3 Á min = À0.28 e Å À3 Table 1 Hydrogen-bond geometry (Å , ).

Gardiner Comment
Hydrozonyl halides are considered as an important precursor in organic synthesis. They have been used extensively as starting material for in situ generation of 1,3-dipoles which in turn can be reacted with a wide range of organic species to generate five and six membered heterocyclic ring compounds. The molecule has two intermolecular NH···O and NH···Cl hydrogen bonds (Table 1) and distance between the molecules is 3.2710 (1) Å. The ring centers are ~2.87 Å apart. The packing is characterized by parallel molecules (perpendicular distance between the centre of gravity of the aromatic rings 3.2710 (1) Å). The molecule is planar and in order to calculate the distance a plane is required to be defined through a set of atoms (phenyl rings) and the distance of any atom of the nearest symmetry related molecules to this plane is then calculated. The distance between the symmetrical related phenyl rings is 3.2710 (1) Å but due to the slippage of centres of gravity of the rings (2.866 Å) there is no π-π interaction between the two rings. Stirring was continued until a solid precipitate was formed (10-20 min.). The reaction mixture was then diluted with cold water (200 ml), the solid product formed was collected, washed several times with cold water, dried and washed with ethanol. A small amount of the product was dissolved in DMF and left at room temperature for 2 days. Yellow needle crystals were isolated, m.p. 393 K.

Refinement
Hydrogen atoms attached to carbons were placed at calculated positions with C-H = 0.95 Å (aromatic) or 0.98-0.99 Å (sp 3 C-atom). Hydrogen atoms attached to nitrogen were located in diff. Fourier maps. All H atoms were refined in the riding-model approximation with isotropic displacement parameters (set at 1.2-1.5 times of the U eq of the parent atom).
The NO 2 group is disorderd where one oxygen atom just off the mirror plane has two positions with relative site occupancies set to 0.4, (O9) and 0.1 (O9B) which generate a further two positions (their mirror images) with the same occupancies.  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.58 e Å −3 Δρ min = −0.28 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > 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 Occ. (