(Z)-2-(2-Oxoindolin-3-ylidene)-N-phenylhydrazinecarbothioamide

In the title compound, C15H12N4OS, the dihedral angle between the nine-membered indolin-2-one ring system and the phenyl ring is 2.72 (7)°. Intramolecular cyclic N—H⋯O and C—H⋯S hydrogen-bonding interactions [graph set S(6)] are present, as are weak N—H⋯N interactions [graph set S(5)]. In the crystal, molecules form centrosymmetric cyclic dimers through pairs of N—H⋯O hydrogen bonds [graph set R 2 2(8)] and these are extended by C—H⋯S interactions. The crystal structure also features weak C—H⋯π interactions.


Experimental
The Schiff base has been synthesized by refluxing the reaction mixture of a hot ethanolic solution (30 ml) of 4-phenyl-3thiosemicarbazide (0.01 mol) and a hot ethanolic solution (30 ml) of isatin (0.01 mol) for 2 h. The precipitate formed during reflux was filtered, washed with cold EtOH and recrystallized from hot EtOH. Yield (m.p.): 90% (510.2-511.6 K).
The yellow crystals were grown in acetone-dimethylformamide (3:1) by slow evaporation at room temperature.

Refinement
N-bound H atoms were located in a difference Fourier map and were refined freely; N-H = 0.87 (2) Å and 0.88 (2) Å.
The remaining H atoms were positioned geometrically and refined using a riding model, with C-H = 0.95 Å and U iso (H) = 1.2U eq (C).

Figure 1
The molecular structure of the title compound, with 50% probability displacement ellipsoids. Dashed lines indicate hydrogen bonds.

sup-3
Acta Cryst. (2012). E68, o962-o963 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.