Crystal structure of 3-chloro-N-(2-nitrophenyl)benzamide

In the title compound, C13H9ClN2O3, the mean plane of the central amide fragment (r.m.s. deviation = 0.016 Å) subtends dihedral angles of 15.2 (2) and 8.2 (2)° with the chloro- and nitro-substituted benzene rings, respectively. An intramolecular N—H⋯O hydrogen bond generates an S(6) ring. In the crystal, molecules are linked by weak C—H⋯O hydrogen bonds, forming C(7) chains which propagate along [010], but no Cl⋯Cl short contacts are observed.


S1. Comment
The crystal structure determination of 3-chloro-N-(2-nitrophenyl)benzamide (I), is part of a study on benzanilides carried out in our research group, and it was obtained from the reaction between 3-chlorobenzoic acid and 2-nitroaniline -2). In this interaction, the C-H in the molecule at (x,y,z) acts as a hydrogen-bond donor to O1 atom of the carbonyl group at (-x+1,+y-1/2,-z+3/2). These interactions generate C(7) chains of molecules along [010]. Other intra N-H···O and N-H···N are observed (see Table 1, Nardelli, 1995). The shorest Cl···Cl contact distance in this structure is 3.943 (3) Å.

S2. Experimental
The title molecule was synthesized taking 0.200 g (1.270 mmol) of 3-chlorobenzoic acid and it was placed under reflux with 2 mL of thionyl chloride for two hours. After this time an equimolar amount of o-nitroaniline, dissolved in 10 mL of acetonitrile and allowed to reflux at constant stirring for 3 hours was added. The final solution was left to slow evaporation to obtain yellow crystals. [m.p. 399 (1)K].

S3. Refinement
All Hm atoms were positioned in geometrically idealized positions, C-H = 0.95 Å, and were refined using a ridingmodel approximation with U iso (H) constrained to 1.2 times U eq of the respective parent atom. H1N atom was found from the Fourier maps and its coordinates were refined freely.

Figure 1
The molecular structure of (I) with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as spheres of arbitrary radius.

Figure 2
Part of the crystal structure of (I), showing the formation of C(7) chains along [010] [Symmetry code: (i) -x + 1, y -1/2,z + 3/2]. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.78 e Å −3 Δρ min = −0.49 e Å −3 Special details Experimental. IR spectra was recorded on a FT-IR SHIMADZU IR-Affinity-1 spectrophotometer. IR (KBr), cm -1 , 3348 (amide N-H); 1684 (amide, C=O); 1499 and 1342 (-NO 2 ) Absorption correction: CrysAlisPro, Agilent Technologies, Version 1.171.34.46 (release 25-11-2010 CrysAlis171 .NET) (compiled Nov 25 2010,17:55:46) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. 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 > 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.