6-Methylpyridine-2(1H)-thione

There are two unique molecules in the asymmetric unit of the title pyridinethione derivative, C6H7NS, each of which adopts the thione rather than the mercaptan form. The rings in both molecules are essentially planar, with maximum deviations from the least-squares planes through all non-H atoms of 0.021 (2) and 0.017 (2) Å. In the crystal structure, the molecules form centrosymmetric cyclic dimers through intermolecular N—H⋯S hydrogen bonds. Additional C—H(methyl)⋯S interactions generate a three-dimensional network.

There are two unique molecules in the asymmetric unit of the title pyridinethione derivative, C 6 H 7 NS, each of which adopts the thione rather than the mercaptan form. The rings in both molecules are essentially planar, with maximum deviations from the least-squares planes through all non-H atoms of 0.021 (2) and 0.017 (2) Å . In the crystal structure, the molecules form centrosymmetric cyclic dimers through intermolecular N-HÁ Á ÁS hydrogen bonds. Additional C-H(methyl)Á Á ÁS interactions generate a three-dimensional network.

Comment
Organic sulfur-containing compounds have been frequently encountered or used in chemical industry (Cui et al., 2009), life science (Saadat et al., 2004) and pharmacy (Qian et al., 2007). Some of them have found their applications in crystal engineering. 2-mercaptopyridine, its 6-methyl substituted and N-oxide derivatives have exhibited rich coordination motifs.
A perspective view of the title compound is shown in Fig. 1. The C-S bond lengths were 1.694 (3) and 1.700 (2) Å, shorter than those in the above-mentioned metal complexes (typically 1.740 Å). This clearly indicates that the neutral title compound in solid state exists as a pyridinethione, while in metal complexes it ligates to metal centers as a pyridinethiolate anion. As shown in Fig. 2, adjacent two molecules are linked by intermolecular N-H···S interactions, forming a cyclic dimer.

Refinement
H atoms bonded to C atoms were placed in geometrically calculated position and were refined using a riding model, the

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 > 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.