Bis(4-ethoxyphenyl) sulfoxide

In the title compound, C16H18O3S, the dihedral angle between the benzene rings is 82.7 (2)°. The O atom of the sulfoxide group is disordered over two orientations with refined occupancy factors of 0.563 (3):0.437 (3). In the crystal, molecules are linked by intermolecular C—H⋯O hydrogen bonds, forming chains along the b axis.

In the title compound, C 16 H 18 O 3 S, the dihedral angle between the benzene rings is 82.7 (2) . The O atom of the sulfoxide group is disordered over two orientations with refined occupancy factors of 0.563 (3):0.437 (3). In the crystal, molecules are linked by intermolecular C-HÁ Á ÁO hydrogen bonds, forming chains along the b axis.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: RZ2577).
1979; Fillion & Fishlock, 2005;Nishimoto et al., 2008). Thiocarbonylbenzenes may be prepared by Friedel-Crafts acylation of benzene derivatives with thiocarbonyl chloride in the presence of anhydrous aluminium chloride. Thus, in order to investigate the potentiality of the method, the title compound was prepared by Friedel-Crafts acylation of phenetol, an electron-rich benzene derivative.
The S=O bond length is shorter than those found in previously reported arylsulfoxides (Casarini et al., 2004;Noland & Kedrowski, 2000). The oxygen atom of the sulfoxide group is disordered over two orientations with site occupancies of 0.563 (3) and 0.437 (3) for the major and minor components, repectively. In the crystal structure, molecules are linkied by intermolecular C-H···O hydrogen bonds (Table 1) to form chains along the b axis.

Experimental
A round-bottomed flask was charged with 1.19 g (10 mmol) of freshly distilled thionyl chloride, 2.44 g (20 mmol) of phenetol and 20 ml of dried dichloromethane, and the mixture was stirred on an ice-water bath followed by addition of 2.67 g (20 mmol) of anhydrous aluminium chloride in a portionwise manner. The resulting mixture was stirred at room temperature overnight and poured into 200 ml of ice-water. The mixture thus formed was exacted with three 50-ml portions of dichloromethane, and the combined exacts were washed with saturated brine, dried over sodium sulfate and evaporated on a rotary evaporator to afford the crude title compound. Pure title compound was obtained by column chromatography.
Crystals suitable for X-ray diffraction were obtained through slow evaporation of a ethyl acetate/petroleum ether (1:10 v/v) solution.