2-[4-(Trifluoromethyl)phenylsulfanyl]benzoic acid

In the title compound, C14H9F3O2S, the dihedral angle between the mean planes of the benzene rings is 88.7 (2)°. The carboxylic acid group is twisted by 13.6 (7)° from the mean plane of its attached aromatic ring. One of the F atoms of the trifluoromethyl group is disordered over two sites in a 0.61 (7):0.39 (7) ratio. In the crystal, inversion dimers linked by pairs of O—H⋯O hydrogen bonds generate R 2 2(8) loops. Weak C—H⋯F interactions are also observed.

In the title compound, C 14 H 9 F 3 O 2 S, the dihedral angle between the mean planes of the benzene rings is 88.7 (2) . The carboxylic acid group is twisted by 13.6 (7) from the mean plane of its attached aromatic ring. One of the F atoms of the trifluoromethyl group is disordered over two sites in a 0.61 (7):0.39 (7) ratio. In the crystal, inversion dimers linked by pairs of O-HÁ Á ÁO hydrogen bonds generate R 2 2 (8) loops. Weak C-HÁ Á ÁF interactions are also observed.
TSY thanks University of Mysore for research facilities and is also grateful to the Principal, Maharani's Science College for Women, Mysore, for giving permission to undertake research. JPJ acknowledges the NSF-MRI program (grant No. CHE-1039027) for funds to purchase the X-ray diffractometer.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB7150).

Comment
The title compound, (I), is a starting material for the synthesis of flupentixol, a well-documented neuroleptic (Young et al., 1976). The crystal structures of α-flupentixol (Post et al., 1975a) and β-flupentixol (Post et al., 1975b) have been reported. As part of our onging studies in this area (Siddegowda et al., 2011a,b), we now describe the crystal structure of (I).
The dihedral angle between the mean planes of the phenyl rings is 88.7 (2)°. The carboxylic acid group (C2/C1/O2/O1) is twisted by 13.6 (7)° from the mean plane of the adjacent benzene ring (C2-C7). Disorder was modeled over two sets of sites for one fluorine atom (F3), of the trifluoromethyl group with an occupancy ratio of 0.61 (7) : 0.39 (7). In the crystal, O-H···O hydrogen bonds (Table 1) link the molecules into dimers with R 2 2 [8] graph-set motifs (Fig. 2). Weak C -H···F interactions are also observed.

Experimental
The title compound was obtained as a gift sample from R. L. Fine chemicals, Bengaluru. It was dissolved in 15 ml of mixture of acetonitrile and dimethyl sulphoxide (1:2), stirred for 10 minutes at room temperature. After few days, irregular colourless crystals were formed by slow evaporation of the solvent mixture (m.p: 413-418 K).

Refinement
All of the H atoms were placed in their calculated positions and then refined using the riding model with Atom-H lengths of 0.93Å (CH) or 0.82Å (OH). Isotropic displacement parameters for these atoms were set to 1.2 (CH) or 1.5 (OH) times U eq of the parent atom. Disorder was modeled over two sets of sites for one fluorine atom (F3) in the trifluoromethyl group with an occupancy ratio of 0.61 (7) : 0.39 (7). Idealised tetrahderal OH refined as rotating group.