Crystal structure of (Z)-2-(5-fluoro-2-oxoindolin-3-ylidene)hydrazinecarbothioamide

In the title compound, C9H7FN4OS, the molecules are almost planar, with an r.m.s. deviation of 0.047 (3) Å from the mean plane defined by the non-H atoms and a maximum deviation of 0.123 (2) Å for the amine N atom. The torsion angle for the N—N—C—S unit is 176.57 (19)°. In the crystal, molecules are linked into inversion dimers via pairs of N—H⋯F hydrogen bonds and, additionally, through N—H⋯O and N—H⋯S hydrogen bonds, building a two-dimensional hydrogen-bond network parallel to the (103) plane. An intramolecular N—H⋯O interaction is also observed.


S2. Synthesis and crystallization
Starting materials were commercially available and were used without further purification. The synthesis was adapted from a procedure reported previously (Freund & Schander, 1902). The hydrochloric acid catalyzed reaction of 5fluorisatin (8,83 mmol) and thiosemicarbazide (8,83 mmol) in ethanol (50 ml) was refluxed for 6 h. After cooling and filtering, the title compound was obtained. Crystals suitable for X-ray diffraction of title compound were obtained in ethanol by the slow evaporation of the solvent.

S3. Refinement
All aromatic H atoms were positioned with idealized geometry and were refined isotropic with U iso (H) = 1.2 U eq (C) using a riding model with C-H = 0.93 Å. The other H atoms were located in difference map but were positioned with idealized geometry and refined isotropic with U iso (H) = 1.2 U eq (N) using a riding model with N-H = 0.86 Å.

Figure 1
The molecular structure of the title compound with labeling and displacement ellipsoids drawn at the 40% probability level. H atoms are drawn isotropically.

Figure 2
A view, down the c axis, of the packing of the title compound showing the two dimensional hydrogen-bond network.

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.