1-(4-Chlorophenyl)-3-(2,4-dichlorobenzoyl)thiourea

The title compound, C14H9Cl3N2OS, has bond lengths and angles which are quite typical for thiourea compounds of this class. The molecule exists in the solid state in its thione form with typical thiourea C=S and C=O bond lengths, as well as shortened C—N bonds. An intramolecular N—H⋯O hydrogen bond stabilizes the molecular conformation. Intermolecular N—H⋯S hydrogen bonds link the molecules to form centrosymmetric dimers.

The title compound, C 14 H 9 Cl 3 N 2 OS, has bond lengths and angles which are quite typical for thiourea compounds of this class. The molecule exists in the solid state in its thione form with typical thiourea C S and C O bond lengths, as well as shortened C-N bonds. An intramolecular N-HÁ Á ÁO hydrogen bond stabilizes the molecular conformation. Intermolecular N-HÁ Á ÁS hydrogen bonds link the molecules to form centrosymmetric dimers.
The N,N-dialkyl-N-aroylthioureas have been effectively used for the extraction of Ni, Pd and Pt metals (Koch, 2001).
Aliphatic and acylthioureas are well known for their fungicidal, antiviral, pesticidal and plant-growth regulating activities (Upadlgaya & Srivastava, 1982;Wegner et al., 1986). Symmetrical and unsymmetrical thioureas have shown antifungal activity against the plant pathogens Pyricularia oryzae and Drechslera oryzae (Krishnamurthy et al., 1999). We are interested in the synthesis of these thioureas as intermediates in the synthesis of novel guanidines and heterocyclic compounds for the systematic study of bioactivity and complexation behaviour and we present here the crystal structure of the title compound. The title compound ( Fig. 1) shows the typical thiourea C═S and C═O double bonds as well as shortened C-N bond lengths. The thiocarbonyl and carbonyl groups are almost coplanar, as reflected by the torsion angles C2-N1-C1-O1 = 9.0 (2)° and N2-C2-N1-C1 = 5.5 (2)°. This is associated with the expected typical thiourea intramolecular N-H···O hydrogen bond (Table). The dihedral angle formed by the two benzene ring planes is 9.35 (9)°. Bond lengths and angles can be regarded as typical for N,N'-disubstituted thiourea compounds as found in the Cambridge Structural Database ver. 5.28 (Allen, 2002) and Khawar Rauf et al., 2006aRauf et al., ,b,c, 2007. Intermolecular N-H···S hydrogen bonds (Table, Fig. 2), link the molecules to dimers. The Cl atoms are not involved in any type of hydrogen bonds.

Experimental
Freshly prepared 2,4-dichlorobenzoyl isothiocyanate (2.3 g, 10 mmol) was stirred in acetone (40 ml) for 20 min. Neat 4-chloroaniline (1.3 g, 10 mmol) was then added and the resulting mixture was stirred for 1.5 h. The reaction mixture was then poured into acidified (pH 4) water and stirred well. The solid product was separated and washed with deionized water and purified by recrystallization from methanol-1,1-dichloromethane (1:10 v/v) to give fine crystals of title compound, with an overall yield of 90%. Full spectroscopic and physical characterization will be reported elsewhere.

Refinement
H atoms were located in a difference map, but those bonded to C were refined with fixed individual displacement parameters U iso (H) = 1.2U eq (C) using a riding model with C-H = 0.95 Å. The H atoms bonded to N were refined freely.