1-Methyl-1H-benzimidazole-2(3H)-thione

The title compound, C8H8N2S, was prepared by the condensation of N-methyl-1,2-phenylenediamine and carbon disulfide. The crystal structure is stabilized by a C—H⋯π interaction between a benzene H atom and the benzene ring of a neighbouring molecule, and by intermolecular N—H⋯S interactions.

The title compound, C 8 H 8 N 2 S, was prepared by the condensation of N-methyl-1,2-phenylenediamine and carbon disulfide. The crystal structure is stabilized by a C-HÁ Á Á interaction between a benzene H atom and the benzene ring of a neighbouring molecule, and by intermolecular N-HÁ Á ÁS interactions.

Structure Reports Online
The benzimidazole unit is essentially planar, with a mean deviation of 0.023 Å from the least-squares plane defined by the nine constituent atoms. The molecular packing ( Fig. 2) is stabilized by a C-H···π interaction between a benzene H atom and the benzene ring of neighbouring molecules, with a C3-H3···Cg i separation of 2.735 (3) Å ( Fig. 2 and Table 1; Cg is the C2-C7 benzene ring, symmetry code as in Fig. 2). Additionally, intermolecular N-H···S interactions in the structure were observed ( Fig. 2 and Table 1; symmetry code as in Fig. 2).

Experimental
Compound (I) was synthesized by the addition of carbondisulfide (0.79 ml, 13.02 mmol) to N-methyl-1,2-phenylenediamine (0.744 ml, 6.55 mmol) in methanol (20 ml). The resulting mixture was stirred for 24 h, at 0°C temperature, giving a clear light yellow solution. The solution was evaporated under reduced pressure to give a light yellow solid, which was recrystallized in methanol/peteroleum ether (9:1) to afford compound (I) (yield : 76%).

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
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 > 2sigma(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.