3-Ethylsulfinyl-2-(4-iodophenyl)-5-methyl-1-benzofuran

In the title compound, C17H15IO2S, the 4-iodophenyl ring makes a dihedral angle of 35.39 (8)° with the plane of the benzofuran fragment. In the crystal, molecules are linked by intermolecular C—H⋯O and C—H⋯π interactions, and an I⋯O contact [3.378 (2) Å]. The crystal structure also exhibits aromatic π–π interactions between the benzene rings of neighbouring molecules [centroid–centroid distance = 3.495 (3) Å].

Cg is the centroid of the C2-C7 benzene ring.
The benzofuran unit is essentially planar, with a mean deviation of 0.021 (2) Å from the least-squares plane defined by the nine constituent atoms. The dihedral angle formed by the benzofuran plane and the 4-iodophenyl ring is 35.39 (8)°. The crystal packing (Fig. 2) is stabilized by a weak intermolecular C-H···O hydrogen bond between the methylene H atom of the ethyl group and the oxygen of the S═O unit, with a C16-16B···O2 i (Table 1), and by an I···O halogen-bonding between the iodine and the oxygen of the S═O unit [I···O2 iii = 3.378 (2) Å; C12-I···O2 iii = 162.46 (7)°] (Politzer et al., 2007). The molecular packing (Fig. 3) is further stabilized by an intermolecular C-H···π interaction between the 4-iodophenyl H atom and the benzene ring of a neighbouring molecule, with a C11-H11···Cg ii (Table 1), and by an aromatic π-π interaction between the benzene rings of neighbouring molecules, with a Cg···Cg v distance of 3.495 (3) Å (Cg is the centroid of the C2-C7 benzene ring).

Experimental
77% 3-chloroperoxybenzoic acid (202 mg, 0.9 mmol) was added in small portions to a stirred solution of 3-ethylsulfanyl-2-(4-iodophenyl)-5-methyl-1-benzofurans (315 mg, 0.8 mmol) in dichloromethane (40 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, 1:2 v/v) to afford the title compound as a colorless solid [yield 79%, m.p. 431-432 K; 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, 0.96 Å for methylene and 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.

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 > 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 I 0.491732 (16)