N-(4-Chlorophenyl)-2,2-diphenylacetamide

In the title compound, C20H16ClNO, an S(6) ring motif is formed via an intramolecular C—H⋯O hydrogen bond. The chloro-substituted benzene ring is almost perpendicular to the benzene rings, forming dihedral angles of 87.33 (9) and 88.69 (9)°. The dihedral angle between the benzene rings is 87.17 (9)°. In the crystal, molecules are linked into chains parallel to the c axis by intermolecular N—H⋯O hydrogen bonds. The crystal packing also features weak C—H⋯π interactions involving the chloro-substituted ring.

In the title compound, C 20 H 16 ClNO, an S(6) ring motif is formed via an intramolecular C-HÁ Á ÁO hydrogen bond. The chloro-substituted benzene ring is almost perpendicular to the benzene rings, forming dihedral angles of 87.33 (9) and 88.69 (9) . The dihedral angle between the benzene rings is 87.17 (9) . In the crystal, molecules are linked into chains parallel to the c axis by intermolecular N-HÁ Á ÁO hydrogen bonds. The crystal packing also features weak C-HÁ Á Á interactions involving the chloro-substituted ring.

Comment
In continuation of our work on the synthesis of amides (Fun et al., 2012a,b,c) we report herein the crystal structure of the title compound.

Experimental
Diphenylacetic acid (0.212 g, 1 mmol), 4-chloroaniline (0.127 g, 1 mmol) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (1.0 g, 0.01 mol) were dissolved in dichloromethane (20 ml). The mixture was stirred in presence of triethylamine at 273 K for about 3 h. The contents were poured into 100 ml of ice-cold aqueous hydrochloric acid with stirring, which was extracted thrice with dichloromethane. The organic layer was washed with saturated NaHCO 3 solution and brine solution, dried and concentrated under reduced pressure to give the title compound. Single crystals were grown from N,N-dimethylformamide by the slow evaporation method. M.p.: 463-465 K.

Refinement
The N-bound H atom was located in a difference Fourier map and was refined freely [N-H = 0.84 (2) Å]. The remaining H atoms were located geometrically and refined using a riding model with U iso (H) = 1.2 U eq (C) [C-H = 0.95 Å].

Computing details
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009   The crystal packing of the title compound, viewed along the a axis. H atoms not involved in the intermolecular interactions (dashed lines) have been omitted for clarity.  (Cosier & Glazer, 1986) operating at 100.0 (1) K. 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.