1,5-Bis(2-oxoindolin-3-ylidene)thiocarbonohydrazide tetrahydrofuran monosolvate

In the thiocarbonohydrazide molecule of the title compound, C17H12N6O2S·C4H8O, the terminal indolin-2-one ring systems make a dihedral angle of 20.13 (6)° with each other. Two intramolecular N—H⋯O hydrogen bonds are present, each of which generates an S(6) ring. In the crystal, N—H⋯O hydrogen bonds lead to a molecular chain running along the b axis. The tetrahydrofuran solvent molecule is disordered over two orientations in a 0.561 (11):0.439 (11) ratio.

In the thiocarbonohydrazide molecule of the title compound, C 17 H 12 N 6 O 2 SÁC 4 H 8 O, the terminal indolin-2-one ring systems make a dihedral angle of 20.13 (6) with each other. Two intramolecular N-HÁ Á ÁO hydrogen bonds are present, each of which generates an S(6) ring. In the crystal, N-HÁ Á ÁO hydrogen bonds lead to a molecular chain running along the b axis. The tetrahydrofuran solvent molecule is disordered over two orientations in a 0.561 (11):0.439 (11) ratio.
Å for atom C14. The configurations around the C-N bonds, stabilized by intramolecular N-H···O hydrogen bonding (Table 1), are same as those observed in the N-methylisatin analogous. The hydrazone molecule is co-crystallized with one molecule of THF which suffers from disorder. The crystal packing contains chains along the b axis formed by intermolecular N6-H6···O1 hydrogen bonds (Table 1 and Fig. 2). The THF molecules are N-H···O bonded to the chain.

Experimental
The Schiff base was prepared as described previously (Bacchi et al., 2005) and grown as X-ray quality crystals from a THF solution at room temperature.

Refinement
C-bound hydrogen atoms were placed at the calculated positions and refined in riding mode with C-H distances of 0.93 Å. The amino hydrogen atoms were located in a difference Fourier map and refined with N-H distance restraints of 0.86 (2) Å. For all the hydrogen atoms U iso (H) were set to 1.2 U eq (carrier atoms). The tetrahydrofuran molecule was found to be disordered over two positions, the site occupancy factor for the major component refined to 0.561 (11). The geometrical parameters of the two disordered components were kept similar by using the SAME command in

1,5-Bis(2-oxoindolin-3-ylidene)thiocarbonohydrazide tetrahydrofuran monosolvate
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.