3,5-Difluorophenyl phenyl sulfone

In the title compound, C12H8F2O2S, which is a precursor of functionalised poly(arylene ether sulfone) polymers, the dihedral angle between the aromatic ring planes is 84.43 (8)°. In the crystal structure, aromatic π–π stacking [centroid–centroid separations = 3.808 (3) and 3.867 (3) Å] helps to establish the packing. A short C—H⋯F contact also occurs.

In the title compound, C 12 H 8 F 2 O 2 S, which is a precursor of functionalised poly(arylene ether sulfone) polymers, the dihedral angle between the aromatic ring planes is 84.43 (8) . In the crystal structure, aromaticstacking [centroid-centroid separations = 3.808 (3) and 3.867 (3) Å ] helps to establish the packing. A short C-HÁ Á ÁF contact also occurs.
3,5-Difluorophenyl phenyl sulfone D. A. Grossie, E. Fossum, A. Elsen and T. Meyer Comment Poly(arylene ether sulfone)s, PAESs, are a class of tough, amorphous polymers that possess excellent thermo and oxidative stability as well as low dielectric constants (Salamon, 1999). Several of these systems have found commercial applications that require hydrolytic and thermal stability. Classically, PAESs are synthesized through nucleophilic aromatic substitution (NAS) reactions of 4-chloro (or fluoro-) phenyl sulfone (I) with various bisphenolates, a well known A~2~ + B~2~ polycondensation, to afford linear PAESs (Attwood et al., 1977, Johnson et al., 1967. In order to tailor the chemical and physical properties of PAESs, it is often desirable to introduce functional groups along or pendant to the backbone. To that end, a geometric isomer of (I), the title compound, (II), has been prepared and successfully polymerized, under NAS conditions, to generate PAESs carrying a pendant phenyl sulfonyl group (Kaiti et al., 2006). The pendant phenyl sulfonyl group provides a unique platform from which to access PAESs bearing a wide variety of functional groups. We now describe the crystal structure of (II) (Fig. 1).
The bond lengths within (I) are all within their expeted ranges of values. Bond angles within the molecule were also mostly observed as expected. The O1-S1-O2 angle is 120.39 (10)° and angles near 108° are seen for Ox-S1-Cy (with x = 1 or 2 and y = 1 or 7). The angle between C1-S1-C7 is 102.68 (10)°, which is smaller than would have been expected, based on prediction or comparison with similar structures in CSD.
Four molecules are present within the unit cell, in two columns in which the fluorine substituted rings are stacked in the c direction with a centroid-centroid separation of 3.867 (3)Å. Neighboring columns are interconnected via π-π interactions between the unsubstituted phenyl rings that lie parallel to each other, separated by 3.808 (3)Å. A short C-H···F contact (Table 1) interconnects the columns within the crystal.

Experimental
In a 250-ml round bottomed flask equipped with a stir bar, addition funnel, condenser, and gas inlet were placed 2.105 g (86.6 mmol) of Mg turnings and enough THF to cover the metal. A solution of 15.94 g (82.5 mmol) of 1-bromo-3,5-difluorobenzene and 50 ml of THF was added slowly to the stirred Mg at room temperature; upon complete addition, the reaction mixture was stirred and allowed to react for 4 h. The resulting solution of 3,5-difluorophenylmagnesium bromide was transferred to an addition funnel and added dropwise to a mixture of 16.01 g (90.8 mmol) of benzenesulfonyl chloride in 60 ml of THF at 273 K. The reaction mixture was stirred overnight. The reaction mixture was then diluted in 500 ml of ether and washed in a separatory funnel with dilute HCl, distilled water, 5% NaHCO 3 , and again with distilled H 2 O. The ether layer was dried over MgSO 4 , filtered, and then evaporated to dryness to afford a yellow solid which was recrystallized, first from ethanol/water and then from hexanes to yield colourless blocks of (I).
supplementary materials sup-2 Figures   Fig. 1. The molecular structure of (I) showing 50% displacement ellipsoids for the non-hydrogen atoms.  Rms deviation of fitted atoms = 0.0028

3,5-Difluorophenyl phenyl sulfone
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 > σ(F 2 ) is used only for calculating Rfactors(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.