3-Fluoro-4-(4-hydroxyphenoxy)benzonitrile

The title compound, C13H8FNO2, was synthesized from 3,4-difluorobenzonitrile and hydroquinone. The dihedral angle between the two aromatic rings is 70.9 (2)°. In the crystal structure, molecules are linked by O—H⋯N hydrogen bonds, forming zigzag chains.

As it is expected substituents at both aromatic rings are coplanar with repect to the aromatic planes. The dihedral angle between the two planes is 70.66°. The molecule is bent with a C6-O1-C7 angle of 118.0 (2)°. The crystal structure is

Experimental
A DMSO (10 ml) solution of hydroquinone (0.0012 mol) and NaOH (0.0024 mol) was stirred at room temperature for 5 h. Then the mixture was heated to 80°C and 3,4-difluorobenzonitrile (0.001 mol) was added dropwise and stirred for 10 h.
Then the mixture was washed with water (30 ml) and extracted with ethyl acetate (three times). The organic solvent was removed under reduced pressure and the resulting crude product was purified by silica gel chromatography (pentane: ethyl acetate mixtures, yield 86%). Single crystals were obtained by slow evaporation of ethyl acetate at room temperature.

Refinement
In the absence of significant anomalous dispersion effects, Friedel pairs were averaged. H atoms were placed in calculated positions with C-H = 0.98 Å (sp), C-H = 0.97 Å (sp 2 ), C-H = 0.93 Å (aromatic). All H atoms were included in the final cycles of refinement using a riding model, with U iso (H)=1.2U eq of the respective carrier atoms.   supplementary materials sup-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 > 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.