(Z)-2-(5-Chloro-2-oxoindolin-3-ylidene)-N-methylhydrazinecarbothioamide

In the title compound, C10H9ClN4OS, an intramolecular N—H⋯O hydrogen-bonding interaction and an N—H⋯N interaction generate ring motifs [graph sets S(6) and S(5), respectively]. In the crystal, molecules form a chain through N—H⋯O hydrogen bonds, and these are extended by N—H⋯S hydrogen-bonding interactions into an infinite three-dimensional network. The crystal structure also exhibits weak C—H⋯π interactions.

In the crystal the molecules form chain substructures through intermolecular N1-H1N1···O1 hydrogen bonds and these are extended by N4-H1N4···S1 hydrogen-bonding interactions into an infinite a three-dimensional network (Table 1,  ring. For symmetry code (iii), see Table 1.

Experimental
The Schiff base has been synthesized by refluxing the reaction mixture of a hot ethanolic solution (30 ml) of 5-methyl-3thiosemicarbazide (0.01 mol) and a hot ethanolic solution (30 ml) of 5-chloroisatin (0.01 mol) for 2 hr. The precipitate formed during reflux was filtered, washed with cold ethanol and recrystallized from hot ethanol. Yield (m.p.): 85% (568.4-569.0 K). The yellow crystals were grown in ethylacetate-DMF (3:1) by slow evaporation at room temperature.

Refinement
Nitrogen bound H atoms were located in a difference Fourier map and were refined freely. The remaining H atoms were positioned geometrically and refined using a riding model with C-H = 0.95 Å (aromatic ring) and C-H = 0.98 Å (methyl group) with U iso (H) = 1.2U eq (aromatic C) and U iso (H) = 1.5U eq (methyl C). The highest residual electron density peak (0.41 eÅ -3 ) is located at 0.73 Å from Cl1 and the deepest hole (-0.32 eÅ -3 ) is located at 0.59 Å from Sl.

Figure 1
The molecular structure and the atom-numbering scheme of the title compound, with 50% probability displacement ellipsoids.

Figure 2
The crystal packing of the title compound viewed down the a axis. Hydrogen bonds are shown as dashed lines. 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.