N-(2-Fluorophenyl)cinnamamide

The title compound, C15H12FNO, was prepared by the reaction of cinnamoyl chloride with 4-fluoroaniline and crystallizes with two molecules A and B in the asymmetric unit. The two unique molecules are closely similar and overlay with an r.m.s. deviation of 0.0819 Å. The fluorobenzene and phenyl rings are inclined to one another at 73.89 (7) and 79.46 (7)°, respectively, in molecules A and B. The amide C—N—C(O)—C portions of the molecules are planar (r.m.s. deviations = 0.035 and 0.028 Å) and are inclined at 45.51 (9) and 47.71 (9), respectively, to the fluorobenzene rings in molecules A and B. The 2-fluoroacetamide units and the benzene rings each adopt E configurations with respect to the C=C bonds. In the crystal structure, intermolecular N—H⋯O hydrogen bonds augmented by weak C—H⋯π interactions link molecules into rows in a head-to-tail fashion along a. Additional weak C—H⋯O contacts further stabilize the packing, forming a three-dimensional network stacked down a.

The title compound, C 15 H 12 FNO, was prepared by the reaction of cinnamoyl chloride with 4-fluoroaniline and crystallizes with two molecules A and B in the asymmetric unit. The two unique molecules are closely similar and overlay with an r.m.s. deviation of 0.0819 Å . The fluorobenzene and phenyl rings are inclined to one another at 73.89 (7) and 79.46 (7) , respectively, in molecules A and B. The amide C-N-C(O)-C portions of the molecules are planar (r.m.s. deviations = 0.035 and 0.028 Å ) and are inclined at 45.51 (9) and 47.71 (9), respectively, to the fluorobenzene rings in molecules A and B. The 2-fluoroacetamide units and the benzene rings each adopt E configurations with respect to the C C bonds. In the crystal structure, intermolecular N-HÁ Á ÁO hydrogen bonds augmented by weak C-HÁ Á Á interactions link molecules into rows in a head-to-tail fashion along a. Additional weak C-HÁ Á ÁO contacts further stabilize the packing, forming a three-dimensional network stacked down a.

Experimental
Cinnamoyl chloride (5.4 mmol) in CHCl 3 was treated with 4-fluoroaniline (21.6 mmol) under a nitrogen atmosphere at reflux for 2 h. Upon cooling, the reaction mixture was diluted with CHCl 3 and washed consecutively with aqueous 1 M HCl and saturated aq NaHCO 3 . The organic layer was dried over anhydrous magnesium sulfate and concentrated under reduced pressure. Crystallization of the residue from CHCl 3 afforded the title compound (87%) as colourless needles: Anal. calcd.

Refinement
The H atoms bound to N1A and N1B were located in a difference map and refined isotropically. All other H-atoms were positioned geometrically and refined using a riding model with d(C-H) = 0.95 Å, U iso = 1.2U eq (C). Fig. 1. The asymmetric unit of (I) with displacement ellipsoids for the non-hydrogen atoms drawn at the 50% probability level.

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.