10-(1,2,2-Trichlorovinyl)-10H-phenothiazine 5,5-dioxide

The title compound, C14H8Cl3NO2S, forms a dimeric structure by intermolecular Cl⋯O=S interactions. The dimers make a two-dimensional array parallel to (101) by other Cl⋯O=S interactions. The two-dimensional network is found to be kept unchanged, although the trichlorovinyl group is disordered (relative occupancies 0.65:0.35).

However, Cl···O=S interactions in heterocycles such as thiophenes and phenothiazines have been reported only in two cases (Douglas et al., 1993;Jovanovic et al., 1986). This is the first report of Cl···O=S interactions in phenothiazine 5,5dioxide compounds.
The dimers make a two-dimensional array on the (101) (Bandera et al., 2007;Choi et al., 2008)). Remarkable contacts cannot be observed between the arrays. The two-dimensional network is found to be kept unchanged, although the trichlorovinyl group is disordered.

Experimental
The title compound was prepared according to a reported procedure (Okuno et al., 2006). The single crystals with sufficient quality for X-ray analysis were obtained by concentration of a dichloromethane solution.

Refinement
The occupancies of disordered trichlorovinyl groups were determined to 0.65 for A and 0.35 for B as both disordered forms have similar thermal parameters. All H atoms were placed at ideal positions and were treated as riding on their parent C atoms. U iso (H) values of the H atoms were set at 1.2U eq (parent atom).

Figure 1
The asymmetric unit of the title compound with atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres. Disordered atoms are discriminated with A/B notation, and the minor disordered form is drawn as open bonds.  A view of the two-dimensional array on the (101) plane. Hydrogen atoms are omitted for clarity. The Cl···O=S interactions are shown as dashed lines. [Symmetry codes: (i) x + 1/2, -y + 1/2, z -1/2; (ii) -x, -y, -z + 1; (iii) -x + 1/2, y -1/2, -z + 1/2]. Special details Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F 2 . R-factor (gt) are based on F. The threshold expression of F 2 > 2.0 σ(F 2 ) is used only for calculating R-factor (gt).