2-(4-Fluorophenyl)-5-iodo-7-methyl-3-phenylsulfinyl-1-benzofuran

In the title compound, C21H14FIO2S, the dihedral angles between the mean plane [r.m.s. deviation = 0.007 (1) Å] of the benzofuran fragment and the pendant 4-fluorophenyl and phenyl rings are 3.66 (7) and 82.37 (6)°, respectively. In the crystal, molecules are linked by pairs of C—H⋯I hydrogen bonds into centrosymmetric dimers, which are further packed into stacks along the b axis by C—H⋯O hydrogen bonds. In addition, the stacked molecules exhibit inversion-related S⋯O contacts [2.9627 (14) Å] involving the sulfinyl groups.

In the title compound, C 21 H 14 FIO 2 S, the dihedral angles between the mean plane [r.m.s. deviation = 0.007 (1) Å ] of the benzofuran fragment and the pendant 4-fluorophenyl and phenyl rings are 3.66 (7) and 82.37 (6) , respectively. In the crystal, molecules are linked by pairs of C-HÁ Á ÁI hydrogen bonds into centrosymmetric dimers, which are further packed into stacks along the b axis by C-HÁ Á ÁO hydrogen bonds. In addition, the stacked molecules exhibit inversion-related SÁ Á ÁO contacts [2.9627 (14) Å ] involving the sulfinyl groups.

Related literature
For background information and the crystal structures of related compounds, see: Choi et al. (2009Choi et al. ( , 2012. For details of sulfinyl-sulfinyl interactions, see: Choi et al. (2008) and for a review of carbonyl-carbonyl interactions, see: Allen et al.  Table 1 Hydrogen-bond geometry (Å , ).
In the title molecule ( Fig. 1), 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 angles between the mean plane of the benzofuran fragment and the pendant 4-fluorophenyl and phenyl rings are 3.66 (7) and 82.37 (6)°, respectively. In the crystal structure ( Fig. 2), molecules are linked by pairs of C-H···I hydrogen bonds into centrosymmetric dimers, which are further packed into stacks along the b axis by C-H···O hydrogen bonds (Table 1). In addition, the crystal packing ( Fig.   2) exhibits a sulfinyl-sulfinyl interaction (Choi et al., 2008) interpreted as similar to a type-II carbonyl-carbonyl interaction (Allen et al., 1998), with S1···O2 iii and O2..S1 iii distance of 2.9627 (14) Å .

Experimental
3-Chloroperoxybenzoic acid (77%, 179 mg, 0.8 mmol) was added in small portions to a stirred solution of 2-(4-fluorophenyl)-5-iodo-7-methyl-3-phenylsulfanyl-1-benzofuran (322 mg, 0.7 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, 2:1 v/v) to afford the title compound as a colorless solid [yield 70%, m.p. 473-474 K; R f = 0.74 (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 benzene at room temperature.

Refinement
All H atoms were positioned geometrically and refined using a riding model, with C-H = 0.95 Å for aryl and 0.98 Å for methyl H atoms. U iso (H) = 1.2U eq (C) for aryl and 1.5U eq (C) for methyl H atoms. The positions of methyl hydrogens were optimized rotationally.    where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.002 Δρ max = 0.37 e Å −3 Δρ min = −0.63 e Å −3 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.