3-Ethylsulfanyl-2-(4-fluorophenyl)-5-phenyl-1-benzofuran

In the title compound, C22H17FOS, the crystal studied was an inversion twin with a 0.42 (18):0.58 (18) domain ratio. The 4-fluorophenyl ring is rotated out of the benzofuran plane, making a dihedral angle of 17.82 (6)°, and the dihedral angle between the 5-phenyl ring and the benzofuran plane is 29.45 (7)°.

In the title compound, C 22 H 17 FOS, the crystal studied was an inversion twin with a 0.42 (18):0.58 (18) domain ratio. The 4-fluorophenyl ring is rotated out of the benzofuran plane, making a dihedral angle of 17.82 (6) , and the dihedral angle between the 5-phenyl ring and the benzofuran plane is 29.45 (7) .
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: NG2718).  (Akgul & Anil, 2003;Soekamto et al., 2003;von Reuss & König, 2004). As a part of our continuing studies of the effect of side chain substituents on the solid state structures of 2,5-diaryl-1-benzofuran analogues (Choi et al., 2006, we report the crystal structure of the title compound (Fig. 1).
The title compound crystallizes as the monoclinic space P21. The crystal studied was an inversion twin with a 0.42 (18) : 0.58 (18) domain ratio. The benzofuran unit is essentially planar, with a mean deviation of 0.019 (1) Å from the least-squares plane defined by the nine constituent atoms. The 4-fluorophenyl ring is rotated out of the benzofuran plane, with a dihedral angle of 17.82 (6)°. The dihedral angle between the phenyl ring and the benzofuran plane is 29.45 (7)°.

Experimental
Zinc chloride (273 mg, 2.0 mmol) was added to a stirred solution of 4-phenylphenol (340 mg, 2.0 mmol) and 2-chloro-2-ethylsulfanyl-4'-fluoroacetophenone (465 mg, 2.0 mmol) in dichloromethane (25 ml) at room temperature, and stirring was continued at the same temperature for 40 min. The reaction was quenched by the addition of water and the organic layer separated, dried over magnesium sulfate, filtered and concentrated in vacuum. The residue was purified by column chromatography (carbon tetrachloride) to afford the title compound as a colorless solid [yield 66 %, m.p. 393-394 K; R f = 0.76 (carbon tetrachloride)]. Single crystals suitable for X-ray diffraction were prepared by evaporation of a solution of the title compound in acetone at room temperature.

Refinement
The reported Flack parameter was obtained by TWIN/BASF procedure in SHELXL (Sheldrick, 2008). All H atoms were geometrically positioned and refined using a riding model, with C-H = 0.95 Å for aryl, 0.99 Å for methylene, and 0.98 Å for methyl H atoms. U iso (H) = 1.2U eq (C) for all H atoms. Fig. 1. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 50 % probability level. H atoms are presented as a small cycles of arbitrary radius.

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 supplementary materials sup-3 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 > 2sigma(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 S 0.50045 (5)