N-(4-Chlorobutanoyl)-N′-[2-(trifluoromethyl)phenyl]thiourea

In the title compound, C12H12ClF3N2OS, the dihedral angle between the benzene ring and the thiourea fragment is 69.41 (5)°. The thiourea N—H atoms adopt an anti conformation, such that one of them forms an intramolecular N—H⋯O hydrogen bond, generating an S(6) ring. In the crystal, both N—H groups form inversion dimers, one via a pair of N—H⋯S hydrogen bonds and one via a pair of N—H⋯O hydrogen bonds. These lead to R 2 2(8) and R 2 2(12) loops, respectively. Weak C—H⋯Cl, C—H⋯F, C—H⋯S and π–π [centroid–centroid separation = 3.7098 (6)Å and slippage = 1.853 Å] interactions also occur.

In the title compound, C 12 H 12 ClF 3 N 2 OS, the dihedral angle between the benzene ring and the thiourea fragment is 69.41 (5) . The thiourea N-H atoms adopt an anti conformation, such that one of them forms an intramolecular N-HÁ Á ÁO hydrogen bond, generating an S(6) ring. In the crystal, both N-H groups form inversion dimers, one via a pair of N-HÁ Á ÁS hydrogen bonds and one via a pair of N-HÁ Á ÁO hydrogen bonds. These lead to R 2 2 (8) and R 2 2 (12) loops, respectively. Weak C-HÁ Á ÁCl, C-HÁ Á ÁF, C-HÁ Á ÁS and -[centroid-centroid separation = 3.7098 (6)Å and slippage = 1.853 Å ] interactions also occur.

Experimental
An equimolar amount of 2-(trifluoromethyl)aniline (1.14 g, 7.09 mmol) in 20 ml acetone was added drop-wise into a stirring acetone solution (75 ml) containing 4-chlorobutanoylchloride (1.00 g, 7.09 mmol) and ammonium thiocyanate (0.54 g, 7.09 mmol). The mixture was refluxed for 1 h. Then, the solution was filtered-off and left to evaporate at room temperature to yield colourless needles.

Figure 2
The crystal packing of the title compound. The H atoms not involved in the intermolecular interactions (dashed lines) have been omitted for clarity.

N-(4-Chlorobutanoyl)-N′-[2-(trifluoromethyl)phenyl]thiourea
Crystal data  (Cosier & Glazer, 1986) operating at 100.0 (1) K. Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 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 Cl1