1-Benzoyl-3,3-dibutylthiourea

The title molecule, C16H24N2OS, is twisted about the central N(H)—C bond with a C—N(H)—C—N torsion angle of −62.67 (15)°. The carbonyl group is twisted out of the plane of the benzene ring, forming a C—C—C=O torsion angle of −25.06 (17)°. In the crystal, molecules related by centres of symmetry are linked by pairs of intermolecular N—H⋯S hydrogen bonds, forming eight-membered {⋯HNCS}2 synthons. These are further connected by weak via C—H⋯O contacts, forming a two-dimensional array in the bc plane.

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010). NG thanks the NITT for a Fellowship. The authors also thank the University of Malaya for support of the crystallographic facility.  (Binzet et al., 2009;Lipowska et al., 1996). These species are also considered as versatile and attractive ligands due to their coordination ability to a wide range of metal centres, either as neutral ligands, or as mono-or di-anions (Henderson et al., 2002;Hallale et al., 2005). Their coordination complexes can also exhibit useful properties. As an example of a recent application, ruthenium(III) complexes containing these ligands have recently been used as catalysts for oxidation of alcohols to carbonyl compounds (Gunasekaran & Karvembu, 2010). In continuation of structural studies of these molecules (Gunasekaran et al., 2010a;Gunasekaran et al., 2010b), (I), the crystal structure of the title compound was carried out.
In (I), the molecule is twisted about the central N1-C8 bond as reflected in the value of the C7-N1-C8-S1 torsion angle of 119.81 (11) ° and C7-N1-C8--N2 of -62.67 (15) ° (see Fig. 1). The carbonyl group is twisted out of the plane of the benzene ring to which it is attached [the C2-C1-C7-O1 dihedral angle = -25.06 (17) °], and the butyl groups lie on opposite sides of the mean plane formed by the N 2 S atoms.
The most prominent intermolecular interactions are of the type N-H···S, occurring between centrosymmetrically related molecules to form an eight-membered {···HNCS} 2 synthon, Table 1. The dimeric aggregates are linked into a 2-D array via C-H···O contacts, Fig. 2 and Table 1. The layers thus formed stack along the a axis, Fig. 3.

Experimental
A solution of benzoyl chloride (0.7029 g, 5 mmol) in acetone (50 ml) was added drop wise to a suspension of potassium thiocyanate (0.4859 g, 5 mmol) in anhydrous acetone (50 ml). The reaction mixture was heated under reflux for 45 min and then cooled to room temperature. A solution of dibutyl amine (0.6462 g, 5 mmol) in acetone (30 ml) was added and the resulting mixture was stirred for 2 h. Hydrochloric acid (0.1 N, 300 ml) was added and the resulting white solid was filtered, washed with water and dried in vacuo. Single crystals of (I) for X-ray diffraction were grown at room temperature from its acetone solution. M. pt. 358-360 K; Yield 76%. FT-IR (KBr) ν(N-H) 3174, ν(C═O) 1688, ν(C═S) 1243 cm -1 .

Refinement
Carbon-bound H-atoms were placed in calculated positions (C-H 0.95 to 0.99 Å) and were included in the refinement in the riding model approximation, with U iso (H) set to 1.2 to 1.5U equiv (C). The N-bound H-atom was located in a difference Fourier map, and was refined with a distance restraint of N-H 0.86±0.01 Å; the U iso value was freely refined.