4-Bromo-N-(di-n-propylcarbamothioyl)benzamide

The synthesis of the title compound, C14H19BrN2OS, involves the reaction of 4-bromobenzoyl chloride with potassium thiocyanate in acetone followed by condensation of the resulting 4-bromobenzoyl isothiocyanate with di-n-propylamine. Typical thiourea carbonyl and thiocarbonyl double bonds, as well as shortened C—N bonds, are observed in the title compound. The short C—N bond lengths in the centre of the molecule reveal the effects of resonance in this part of the molecule. The asymmetric unit of the title compound contains two crystallographically independent molecules, A and B. There is very little difference between the bond lengths and angles of these molecules. In molecule B, one di-n-propyl group is twisted in a −antiperiplanar conformation with C—C—C—H = −179.1 (3)° and the other adopts a −synclinal conformation with C—C—C—H = −56.7 (4)°; in molecule A the two di-n-propyl groups are twisted in + and −antiperiplanar conformations, with C—C—C—H = −179.9 (3) and 178.2 (3)°, respectively. In the crystal, the molecules are linked into dimeric pairs via pairs of N—H⋯S hydrogen bonds.

The synthesis of the title compound, C 14 H 19 BrN 2 OS, involves the reaction of 4-bromobenzoyl chloride with potassium thiocyanate in acetone followed by condensation of the resulting 4-bromobenzoyl isothiocyanate with di-n-propylamine. Typical thiourea carbonyl and thiocarbonyl double bonds, as well as shortened C-N bonds, are observed in the title compound. The short C-N bond lengths in the centre of the molecule reveal the effects of resonance in this part of the molecule. The asymmetric unit of the title compound contains two crystallographically independent molecules, A and B. There is very little difference between the bond lengths and angles of these molecules. In molecule B, one di-n-propyl group is twisted in a Àantiperiplanar conformation with C-C-C-H = À179.1 (3) and the other adopts a Àsynclinal conformation with C-C-C-H = À56.7 (4) ; in molecule A the two di-n-propyl groups are twisted in + and Àantiperiplanar conformations, with C-C-C-H = À179.9 (3) and 178.2 (3) , respectively. In the crystal, the molecules are linked into dimeric pairs via pairs of N-HÁ Á ÁS hydrogen bonds.  (2003b, 2006), and references therein. For general background, see: Koch (2001); El Aamrani et al. (1998Aamrani et al. ( , 1999; Arslan et al. (2006Arslan et al. ( , 2007a. For related compounds, see: Khawar Rauf et al. (2009a,b,c,d); Arslan et al. (2003aArslan et al. ( , 2004. For bond-length data, see: Allen et al. (1987).  Table 1 Hydrogen-bond geometry (Å , ).  (Koch, 2001;El Aamrani et al., 1998, 1999. The structures of thiourea derivatives and its metal complexes have been determined during the last years. The title compound derivative acts as a bidentate ligand coordinating through the S atom and the O atom.
The title compound, 4-bromo-N-(di-n-propylcarbamothioyl)benzamide, (I), is another example of our newly synthesized thiourea derivatives that contains both aryl and alkyl groups.
The molecular structure of the title compound is depicted in Fig. 1. The asymmetric unit of the title compound contains two crystallographically independent molecules A (atom numbering 1xx) and B (2xx). There is very little difference between the bond lengths and angles of these molecules.
The molecules of title compound are linked by paired N-H···S hydrogen bonds into centrosymmetric dimers. Details of the symmetry codes and hydrogen bonding are given in Table 1 and Fig. 2.

Experimental
The title compound was prepared with a procedure similar to that reported in the literature (Arslan et al., 2003b;Özer et al., 2009). A solution of 4-bromobenzoyl chloride (0.01 mol) in acetone (50 ml) was added dropwise to a suspension of potassium thiocyanate (0.01 mol) in acetone (30 ml) (Fig. 3). The reaction mixture was heated under reflux for 30 min, and then cooled to room temperature. A solution of di-n-propylamine (0.01 mol) in acetone (10 ml) was added and the resulting mixture was stirred for 2 h. Hydrochloric acid (0.1 N, 300 ml) was added to the solution, which was then filtered.
The solid product was washed with water and purifed by recrystallization from an ethanol-dichloromethane mixture (1:2

Refinement
H atoms were clearly identified in difference syntheses. H atoms attached to nitrogens were located from a difference Fourier map and refined freely. The rest H atoms refined at idealized positions riding on the C atoms with C-H = 0.95-0.99 Å, and U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2U eq (C) for other H atoms.
All CH 3 H atoms were allowed to rotate but not to tip. For C203 and C204 neither anisotropic refinement nor split model provided successful results, so an isotropic model was used that gave sensible geometries but some electron density residuals nearby. Fig. 1. The molecular structure of (I). Displacement ellipsoids are drawn at the 50% probability level.

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. 120.5 C212-C213-H21C 120.7 C114-C113-H11C 120.5 C214-C213-H21C 120.7 C109-C114-C113 120.2 (3) C209-C214-C213 120.1 (3) C109-C114-H11D 119.9 C209-C214-H21D 120.0