5-[(E)-(5-Bromo-2-hydroxybenzylidene)amino]-1,3,4-thiadiazole-2(3H)-thione

In the title molecule, C9H6BrN3OS2, the dihedral angle between the benzene ring and the five-membered ring is 5.5 (3)°. An intramolecular O—H⋯N hydrogen bond forms an S(6) ring motif. In the crystal, N—H⋯S hydrogen bonds link molecules into centrosymmetric dimers creating R 2 2(8) ring motifs. In addition, there are intermolecular S⋯S [3.430 (2) Å] contacts. The crystal used was a non-merohedral twin with a ratio of 0.113 (3):0.887 (3) for the components.

In the title molecule, C 9 H 6 BrN 3 OS 2 , the dihedral angle between the benzene ring and the five-membered ring is 5.5 (3) . An intramolecular O-HÁ Á ÁN hydrogen bond forms an S(6) ring motif. In the crystal, N-HÁ Á ÁS hydrogen bonds link molecules into centrosymmetric dimers creating R 2 2 (8) ring motifs. In addition, there are intermolecular SÁ Á ÁS

Comment
The biological versatility of compounds incorporating a thiadiazole ring is well known (Kumar et al., 1988;Yadav et al., 1989). In continuation of our work on the crystal structure of thione-Schiff base ligands (Kargar et al., 2011), we have determined the crystal structure of the title compound.
The asymmetric unit of the title compound is shown in Fig. 1. The bond lengths (Allen et al., 1987) and angles are within the normal ranges and are comparable to related structures (Kargar et al., 2011;Zhang, 2003).

Experimental
The title compound was synthesized by adding 5-bromo-salicylaldehyde (1 mmol) to a solution of 5-aminothiophene-2-thiol (1 mmol) in ethanol (30 ml). The mixture was refluxed with stirring for half an hour. The resultant solution was filtered.
Yellow single crystals of the title compound suitable for X-ray structure determination were recrystallized from ethanol by slow evaporation of the solvent at room temperature over several days.

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 > 2sigma(F 2 ) is used only for calculating R-factors(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq