1-(4-Chlorophenyl)-3-(2-thienylcarbonyl)thiourea

The title compound, C12H9ClN2OS2, exists in the thioamide form with an intramolecular N—H⋯O hydrogen bond across the thiourea and the carbonyl group. The dihedral angle between the rings is 10.36 (11)°. In the crystal structure, molecules are linked into chains by weak intermolecular C—H⋯Cl hydrogen-bonding interactions.


Related literature
For general background to the biological activity of thiourea derivatives, see: Xu et al. (2004); Gu et al. (2007). For related structures, see: Saeed et al. (2008Saeed et al. ( , 2009. For the cytotoxicity of anticancer drugs to normal cells in cancer therapy, see: Saeed et al. (2010).

Comment
Thiourea and its derivatives are an important class of organic compounds in which sulfur is the major ligand atom which plays an important role in coordination chemistry with transition metals. Thiourea and its derivatives have found extensive applications in the fields of medicine, agriculture and analytical chemistry. Thioureas are also known to exhibit a wide range of biological activities including anticancer (Saeed et al., 2010), antifungal (Saeed et al., 2008), antiviral, antibacterial, anti-tubercular, anti-thyroidal, herbicidal and insecticidal activities, organocatalyst (Gu et al., 2007) and as agrochemicals (Xu et al., 2004).

Experimental
A solution of 2-thiophenecarbonyl chloride (0.01 mol) in anhydrous acetone (80 ml) was added dropwise to a suspension of ammonium thiocyanate (0.01 mol) in anhydrous acetone (50 ml) and the reaction mixture was refluxed for 50 minutes. After cooling to room temperature, a solution of 4-chloroaniline (0.01 mol) in dry acetone (25 ml) was added and the resulting mixture refluxed for 2 h. The reaction mixture was poured into five times its volume of cold water, upon which the thiourea precipitated. The product was recrystallized from ethanol as white block crystals.

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.