3-Ethylsulfinyl-2-(4-fluorophenyl)-5-iodo-1-benzofuran

In the title compound, C16H12FIO2S, the 4-fluorophenyl ring is rotated slightly out of the benzofuran plane, as indicated by the dihedral angle of 4.48 (5)°. In the crystal structure, pairs of I⋯O halogen bonds [I⋯O = 3.123 (1) Å] link the molecules into centrosymmetric dimers. These dimers are further linked via aromatic π–π interactions between the benzene and 4-fluorophenyl rings of neighbouring molecules [centroid–centroid distance = 3.620 (3) Å].

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: DS2026).

Experimental
77% 3-Chloroperoxybenzoic acid (202 mg, 0.9 mmol) was added in small portions to a stirred solution of 3-ethylsulfanyl-2-(4-fluorophenyl)-5-iodo-1-benzofuran (358 mg, 0.9 mmol) in dichloromethane (30 mL) at 273 K. After being stirred at room temperature for 4h, the mixture was washed with saturated sodium bicarbonate solution and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated at reduced pressure. The residue was purified by column chromatography (hexane-ethyl acetate, 1:1 v/v) to afford the title compound as a colorless solid [yield 80%, m.p. 446-447 K; R f = 0.51 (hexane-ethyl acetate, 1:1 v/v)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a solution of the title compound in chloroform at room temperature.

Refinement
All H atoms were positioned geometrically and refined using a riding model, with C-H = 0.95 Å for aryl, 0.98 Å for methylene, and 0.00 Å for methyl H atoms. U iso (H)= 1.2U eq (C) for aryl and methylene H atoms, and 1.5U eq (C) for methyl H atoms.
supplementary materials sup-2 Figures 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 spheres 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 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.