N,N-Diethyl-N′-phenylacetylthiourea

The title thiourea molecule, C13H18N2OS, adopts a folded conformation due to the steric hindrance of the two ethyl groups and the acetyl group. In the crystal structure, the acetyl O atom is not involved in hydrogen bonding, but intermolecular N—H⋯S hydrogen bonds link the molecules into centrosymmetric dimers.

The title thiourea molecule, C 13 H 18 N 2 OS, adopts a folded conformation due to the steric hindrance of the two ethyl groups and the acetyl group. In the crystal structure, the acetyl O atom is not involved in hydrogen bonding, but intermolecular N-HÁ Á ÁS hydrogen bonds link the molecules into centrosymmetric dimers.
Financial support of this work by the Foundation of Northwest University for Nationalities are acknowledged.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: CV2467).

Comment
Thiourea and its derivatives attract special attention in recent years because of their broad applications, such as anion recognition, nonlinear optical material, catalysis etc., and also due to high bioactivity and good coordination ability (Choi et al., 2008;Kushwaha et al., 2008;Jones et al. 2008;Su et al., 2006). For a long time, we have being interested in the influence of non-covalent interactions related to the substituted groups on the conformations of thiourea derivatives as well as their coordination abilities. Thiourea derivatives with different substituted groups coordinate different transition metal ions providing various structures. One of the key influence factors in coordination reactions is non-covalent interaction.
However, the central ion also plays and important role. Triangle conformation is commonly observed in the coordination compound of benzoylthiourea with Cu(I) (Xian et al., 2004). However, Cu 6 cluster structure was also obtained (Su et al., 2005). Herewith we present the crystal structure of the title compound, (I).
The conformation and the packing diagram of (I) are shown in Figures 1 and 2, respectively. It can be seen that the title compound has a folded conformation which is similar to the structure we obtained before (CCDC No. 699688). The dihedral angle between the benzene ring and the plane O1/ N1/C7/C8 is 69.12 (6)°, and the dihedral angle between the benzene ring and the plane S1/C9/N1/N2 is 67.19 (6)°. Apparently, stereo-hindrance effect of two ethyl groups and acetyl group is the main influence factor to the folded conformation. Because of the absence of hydrogen atom on N2, the acetyl oxygen atom does not take part in hydrogen bonding interactions. This is different from the other carbonylthiourea derivatives (Su et al., 2006;Xian, 2008), in which the carbonyl oxygen atom often forms a six-membered hydrogen bonding ring. However, thiocarbonyl sulfur atom is involved in an intermolecular N-H···S hydrogen bond (Table 1), linking two molecules into centrosymmetric dimer, that was eralier observed in related structures (Su, 2007;Xian, 2008).

Experimental
All reagents and organic solvents were of analytical reagent grade and commercially available. Phenylacetyl chloride (1.55 g) was treated with ammonium thiocyanate (1.20 g) in CH 2 Cl 2 under solid-liquid phase transfer catalysis conditions, using 3% polyethylene glycol-400 as catalyst, to give the corresponding phenylacetyl isothiocyanate, which was reacted with diethylamine (0.73 g) to give the title compound. The solid was separated from the liquid phase by filtration, washed with CH 2 Cl 2 and then dried in air. Colorless single crystals suitable for X-ray analysis were obtained after one week by slow evaporation of an chloroform solution. The infrared spectrum was recorded in the range of 4000-400 cm -1 on a Nicolet

Refinement
All H atoms were placed in calculated positions (C-H = 0.93-0.97 Å, N-H = 0.86 Å) and refined using the riding model approximation, with U iso (H) = 1.2 or 1.5 U eq of the parent atom. Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 40% probability level.  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 Rfactors(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.