N-(3-Chloro-4-fluorophenyl)-2,2-diphenylacetamide

In the title compound, C20H15ClFNO, the dihedral angles between the mean planes of the acetamide group and the chlorofluoro-substituted benzene ring and the two phenyl rings are 10.8 (8), 81.9 (7) and 85.8 (5)°, respectively. The crystal packing is stabilized by N—H⋯O hydrogen bonds and weak C—H⋯O intermolecular interactions, forming infinite chains along the c axis.

In the title compound, C 20 H 15 ClFNO, the dihedral angles between the mean planes of the acetamide group and the chlorofluoro-substituted benzene ring and the two phenyl rings are 10.8 (8), 81.9 (7) and 85.8 (5) , respectively. The crystal packing is stabilized by N-HÁ Á ÁO hydrogen bonds and weak C-HÁ Á ÁO intermolecular interactions, forming infinite chains along the c axis.

Experimental
Diphenylacetyl chloride (0.230 g, 1 mmol) and 3-chloro-4-fluoroaniline (0.145 g, 1 mmol) were dissolved in dichloromethane (20 mL). The mixture was stirred in the presence of triethylamine at 273 K for about 3 h (Fig. 1). The contents were poured into 100 ml of ice-cold aqueous hydrochloric acid with stirring, which was extracted three times with dichloromethane. The organic layer was washed with saturated NaHCO 3 and brine solutions, dried and concentrated under reduced pressure to give the title compound. Single crystals were grown from toluene by the slow evaporation method (M.P.: 427 K).

Refinement
The N-H atom bonded to N1 was located in the diference Fourier map and refined isotropically with N-H distance constrained to 0.86 (2) Å. All C-bound H atoms were placed in their calculated positions and included in the refinement in the riding model approximation with C-H lengths of 0.95 Å for aromatic and 1.00 Å for methyne H atoms and temperature factors set to 1.2 times U eq of the parent atom. 1668 Friedel pairs were measured.

Special details
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 Rfactors(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