6-Nitro-1,3-benzothiazole-2(3H)-thione

In the title molecule, C7H4N2O2S2, the nitro group is twisted by 5.5 (1)° from the plane of the attached benzene ring. In the crystal, N—H⋯S hydrogen bonds link pairs of molecules into inversion dimers, which are linked by weak C—H⋯O interactions into sheets parallel to (101). The crystal packing exhibits short intermolecular S⋯O contacts of 3.054 (4) Å and π–π interactions of 3.588 (5) Å between the centroids of the five- and six-membered rings of neighbouring molecules.

In the title molecule, C 7 H 4 N 2 O 2 S 2 , the nitro group is twisted by 5.5 (1) from the plane of the attached benzene ring. In the crystal, N-HÁ Á ÁS hydrogen bonds link pairs of molecules into inversion dimers, which are linked by weak C-HÁ Á ÁO interactions into sheets parallel to (101). The crystal packing exhibits short intermolecular SÁ Á ÁO contacts of 3.054 (4) Å andinteractions of 3.588 (5) Å between the centroids of the five-and six-membered rings of neighbouring molecules.
In (I) (Fig.1), the nitro group is twisted at 5.5 (1)° from the plane of the attached benzene ring. Intermolecular N-H···S hydrogen bonds (Table 1) link two molecules into centrosymmetric dimer, and weak C-H···O interactions (Table 1) link further these dimers into sheets parallel to (101). The hydrogen bond N-H···S is similar to that reported for 2-mercaptobenzothiazole (Chesick & Donohue, 1971). The crystal packing (Fig. 2) exhibits short intermolecular S···O contacts of 3.054 (4) Å and π-π interactions proved by short distance of 3.588 (5) Å between the centroids of the five-and sixmembered rings from the neighbouring molecules.

Experimental
A mixture of AgCl (0.2 mmol) and bis(diphenylphosphino)methane (0.2 mmol) in MeOH and CH 2 Cl 2 (10 mL, v/v = 1:1) was stirred for 3 h. The insoluble residues were removed by filtration. The filtrate was then evaporated slowly at room temperature for a week to yield colourless crystalline product.
The title compound was prepared by dissolving 0.0587 g colourless product mentioned above in MeOH and CH 2 Cl 2 (10 mL, v/v = 3:7), adding 2-mercapto-6-nitrobenzothiazole (0.2 mmol) into the solution, stirring for 4 h. Subsequent slow evaporation of the yellow filtrate resulted in the formation of yellow crystals.

Refinement
All H atoms were geometrically positioned [C-H 0.93 Å; N-H 0.86 Å], and included in the final refinement in the riding model approximation, with U iso (H) = 1.2 U eq of the parent atom.

Figure 2
A portion of the crystal packing viewed approximately along the a axis. Dashed lines indicate short N···S and O···S contacts. H atoms omitted for clarity. 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 R-factors(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.