3-[(E)-(4-Chlorobenzylidene)amino]-1-phenylthiourea

In the title compound, C14H12ClN3S, the dihedral angle between the terminal benzene rings is 56.6 (2)°; the benzene rings lie to the same side of the molecule. The major twist in the molecule occurs around the Car—N bond (ar is aromatic) [C—N—C—C = 49.9 (5)°]. The configuration about the N=C bond [1.271 (4) Å] is E. The amine H atoms lie on opposite sides of the molecule with one forming an intramolecular N—H⋯N(imine) hydrogen bond and an S(5) ring. In the crystal, centrosymmetric dimers are formed via {⋯HNC=S}2 synthons.

In the title compound, C 14 H 12 ClN 3 S, the dihedral angle between the terminal benzene rings is 56.6 (2) ; the benzene rings lie to the same side of the molecule. The major twist in the molecule occurs around the C ar -N bond (ar is aromatic) [C-N-C-C = 49.9 (5) ]. The configuration about the N C bond [1.271 (4) Å ] is E. The amine H atoms lie on opposite sides of the molecule with one forming an intramolecular N-HÁ Á ÁN(imine) hydrogen bond and an S(5) ring. In the crystal, centrosymmetric dimers are formed via {Á Á ÁHNC S} 2 synthons.

Comment
The title compound, (I), was investigated in continuation of structural studies of substituted thiosemicarbazone molecules (Kayed et al., 2008). The configuration about the N3═C8 bond [1.271 (4) Å] in (I), Fig. 1, is E. The C1-benzene ring is twisted out of the plane of the thiourea moiety as seen in the value of the C7-N1-C1-C2 torsion angle of 49.9 (5)°; the dihedral angle between the C7,N1,N2,S1 [r.m.s. = 0.0155 Å] and C1-C6 planes is 51.06 (13) °. By contrast, the C9-benzene ring is co-planar with the imine moiety, with N3-C8-C9-C10 being -6.3 (5) °. The dihedral angle formed between the benzene rings is 56.6 (2) °. The amine groups lie on opposite sides of the molecule allowing for the formation of an intramolecular N1-H1n···N3 hydrogen bond, Table 1. The result is that the benzene rings lie to the same side of the molecule. Overall the conformation of the molecule is a twisted U-shape. The geometric parameters in and the overall conformation of (I) match very closely those found in the unsubstituted parent compound (Cunha et al., 2007).
The major feature of the crystal packing is the formation of centrosymmetric dimers via N-H···S hydrogen bonds, Table   1 and Fig. 2.

Refinement
Carbon-bound H-atoms were placed in calculated positions (C-H 0.93 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 atoms were refined with the distance restraint Fig. 1. The molecular structure of of (I) showing displacement ellipsoids at the 50% probability level.

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The 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 > 2σ(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.