5-Bromo-3-ethylsulfinyl-2-(4-fluorophenyl)-1-benzofuran

In the title compound, C16H12BrFO2S, the 4-fluorophenyl ring is rotated out of the benzofuran plane, as indicated by the dihedral angle of 5.94 (5)°. The crystal structure exhibits aromatic π–π interactions between the benzene ring and the 4-fluorophenyl ring of an adjacent molecule [centroid–centroid distance = 3.632 (2) Å], and a Br⋯O halogen bond with a Br⋯O distance of 3.101 (1) Å.

In the title compound, C 16 H 12 BrFO 2 S, the 4-fluorophenyl ring is rotated out of the benzofuran plane, as indicated by the dihedral angle of 5.94 (5) . The crystal structure exhibits aromaticinteractions between the benzene ring and the 4-fluorophenyl ring of an adjacent molecule [centroidcentroid distance = 3.632 (2) Å ], and a BrÁ Á ÁO halogen bond with a BrÁ Á ÁO distance of 3.101 (1) Å .

Experimental
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SI2236).
The benzofuran unit is essentially planar, with a mean deviation of 0.007 (1) Å from the least-squares plane defined by the nine constituent atoms. The dihedral angle formed by the plane of the benzofuran and the 4-fluorophenyl ring is 5.94 (5)°. The crystal packing ( Fig. 2) is stabilized by aromatic π-π interactions between the benzene ring and the 4-fluorophenyl ring of an adjacent molecule. The Cg1-Cg2 i distance is 3.632 (2) Å (Cg1 and Cg2 are the centroids of the C2-C7 benzene ring and the C9-C14 4-fluorophenyl ring, respectively). The crystal packing (Fig. 2) is further stabilized by a Br···O halogen bond between the bromine and the oxygen of the S═O unit [Br···O2 ii = 3.101 (1) Å; C-Br···O2 = 168.51 (6)°] (Politzer et al., 2007).

Experimental
77% 3-Chloroperoxybenzoic acid (208 mg, 0.93 mmol) was added in small portions to a stirred solution of 5-bromo-3ethylsulfanyl-2-(4-fluorophenyl)-1-benzofuran (298 mg, 0.85 mmol) in dichloromethane (30 mL) at 273 K. After being stirred at room temperature for 3h, the mixture was washed with saturated sodium bicarbonate solution and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated in vacuum. The residue was purified by column chromatography (hexane-ethyl acetate, 2:1 v/v) to afford the title compound as a colorless solid [yield 83%, m.p. 428-429 K; R f = 0.58 (hexane-ethyl acetate, 2:1 v/v)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a solution of the title compound in tetrahydrofuran at room temperature.

Refinement
All H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93 Å for aryl, 0.97 Å for methylene, and 0.96 Å for methyl H atoms. U iso (H) = 1.2U eq (C) for all H atoms.

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.