Methyl 3-(pyridin-4-ylmethylidene)dithiocarbazate

There are two independent molecules in the asymmetric unit of the title molecule, C8H9N3S2, both of which exhibit an E conformation with the pyridine ring and dithiocarbazate fragment located on opposite sides of the C=N bond. The pyridine ring and dithiocarbazate group are approximately coplanar, with dihedral angles of 4.74 (1) and 8.77 (1)° between their planes in the two molecules. In the crystal, molecules are linked to each other via N—H⋯N hydrogen bonds, forming zigzag chains parallel to [10-1].


Comment
The derivatives of the title compound, (I), are often used as coordinating ligands in the metal complexes (Wu et al., 2001;Fun et al. 2001). Herewith, in this study, we report the crystal structure of the title compound (I). The dithiocarbazate moiety shows an E configuration about the C(6A)-N(2A) and N(3A)-C(7A) bonds.Through planar as whole, the molecules comprise two planar fragments, namely the pyridine moiety and dithiocarbazate moiety with dihedral angles The value for the C=S bond of two molecules is almost same with corresponding C=S bond of related compounds. Also, the pairs of centrosymmetrically related molecules are linked into dimers by pairs of N(1A)···H(3B) and N(1B)···H(3A) hydrogen bonds.

Experimental
A hot solution of S-Methyldithiocarbazate(0.488 mg, 4 mmol) in ethanol (30 mL) was mixed with a 4-formylpyridine (0.535 mg, 5 mmol) in ethanol 10 mL and the reaction mixture was reflux. After one hour, precipitated was appeared.

Refinement
All hydrogen atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with C -H = 0.93 Å and U iso (H) = 1.2 U eq .  The molecular structure of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms have been omitted.

Figure 2
The H-bond diagram of the title molecule (I).  A packing diagram.

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