(E)-2-[1-(3-Chloro-4-fluorophenyl)ethylidene]hydrazinecarbothioamide

In the crystal of the title compound, C9H9ClFN3S, the molecules are interconnected by N—H⋯S and N—H⋯F hydrogen bonds. There are two different N—H⋯S hydrogen bond: the stronger one links molecules into infinite chains along the b axis with graph-set motif C(4), while the weaker N—H⋯S hydrogen bond combines with the previous one into an R 2 2(8) network. Moreover, the chains are linked into layers parallel to (102) by weak N—H⋯F hydrogen bonds, which form an R 2 2(22) ring motif. In addition, there are also weak π–π interactions between the benzene rings of adjacent molecules [centroid–centroid distance = 3.8997 (15) Å].

In the crystal of the title compound, C 9 H 9 ClFN 3 S, the molecules are interconnected by N-HÁ Á ÁS and N-HÁ Á ÁF hydrogen bonds. There are two different N-HÁ Á ÁS hydrogen bond: the stronger one links molecules into infinite chains along the b axis with graph-set motif C(4), while the weaker N-HÁ Á ÁS hydrogen bond combines with the previous one into an R 2 2 (8) network. Moreover, the chains are linked into layers parallel to (102) by weak N-HÁ Á ÁF hydrogen bonds, which form an R 2 2 (22) ring motif. In addition, there are also weakinteractions between the benzene rings of adjacent molecules [centroid-centroid distance = 3.8997 (15) Å ].
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FB2232).
Thiosemicarbazones constitute an important class of N, S donor ligands and have been investigated because of their chemistry and biological activities (Kasuga et al., 2001;Fonari et al., 2003;Kizilcikli et al., 2004;Amoedo et al., 2006;Mirsha et al., 2006;Kovala-Demertzi et al., 2007;Tarafder et al., 2008.) In order to search for new thiosemicarbazones, the title compound has been synthesized and its crystal structure is reported here.
In addition, there are also present weak π-electron-π-electron interactions between the benzene rings of the adjacent molecules (the centroid-the centroid distance equals to 3.8997 (15) Å; the symmetry code: 2 -x, 1 -y, -z). Moreover, there is also even a weaker π-electron-π-electron ring interaction between another benzene ring from the other side with the centroid-centroid distance equal to 4.3962 (15)Å (the symmetry code: 2 -x, -y, -z).

Experimental
The title compound was synthesized by the reaction of hydrazinecarbothioamide (1 mmol, 91.1 mg) with 1-(3-chloro-4fluoro-phenyl)-ethanone (1 mmol, 172.6 mg) in anhydrous ethanol (20 ml) under reflux conditions (353 K) for 6 h. The solvent was removed under reduced pressure and the solid product has been recrystallized from 10 ml of anhydrous ethanol.

Refinement
All the H atoms could be discerned in the difference electron density map. However, they were situated into the idealized positions and refined within the riding atom approximation. The used constraints: N primary/secondary amine -H primary/secondary amine =0.86; C aryl -H aryl = 0.93; C methyl -H methyl = 0.96 Å. U iso (H primary/secondary amine/aryl )=1.2 U eq (C primary/secondary supplementary materials sup-2 amine/aryl ); U iso (H methyl ) =1.5U eq (C methyl ). A rotating group model was used for the refinement of the positions of the methyl group. The minimal and the maximal residual electron densities were located at 0.85 and 0.70 Å from Cl1, respectively.
Figures Fig. 1. The title molecule with displacement ellipsoids drawn at the 30% 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.