N-Phenyl-2-(1,2,3,4-tetrahydronaphthalen-1-ylidene)hydrazinecarbothioamide

The conformation of the title molecule, C17H17N3S, is stabilized by an intramolecular N—H⋯N hydrogen bond involving the azometinic group. The dihedral angle between the two aromatic rings is 36.49 (06)°. The non-aromatic ring of the tetralone substituent adopts a sofa conformation. In the crystal, molecules are linked by pairs of N—H⋯S hydrogen bonds related via centres of symmetry, forming dimers.

The conformation of the title molecule, C 17 H 17 N 3 S, is stabilized by an intramolecular N-HÁ Á ÁN hydrogen bond involving the azometinic group. The dihedral angle between the two aromatic rings is 36.49 (06) . The non-aromatic ring of the tetralone substituent adopts a sofa conformation. In the crystal, molecules are linked by pairs of N-HÁ Á ÁS hydrogen bonds related via centres of symmetry, forming dimers.

Comment
Thiosemicarbazone derivatives have a wide range of pharmacological properties. For example, ketonethiosemicarbazones show pharmacological activity against melanogenesis in melanoma B16 cells (Thanigaimalai et al., 2011). As part of our study on synthesis of thiosemicarbazone compounds, we report herein the crystal structure of a derivative of 2-(1,2,3,4-Tetrahydronaphthalen-1-ylidene)hydrazinecarbothioamide (Oliveira et al., 2012). The title compound (Figure 1), in which the molecular structure matches the asymmetric unit, is not planar and the dihedral angle between the two aromatic rings  Table 1).

Experimental
Starting materials were commercially available and were used without further purification. The tetralone-thiosemicarbazone derivative synthesis was adapted from a procedure reported previously (Freund & Schander, 1902). The hydrochloric acid catalyzed reaction of tetralone (8,83 mmol) and 4-phenylthiosemicarbazide (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 the title compound were obtained in tethahydrofuran by the slow evaporation of solvent.

Refinement
All H atoms were located in difference map but were positioned with idealized geometry and were refined using a riding model with U iso (H) = 1.2 U eq (C and N) with C-H = 0.95 Å for aromatic, C-H = 0.99 Å for methylene and N-H = 0.88 Å for N-H H atoms.  The molecular structure of the title compound with labeling and displacement ellipsoids drawn at the 50% probability level, with intramolecular hydrogen bonding shown as dashed line.

Figure 2
Crystal structure of the title compound with inter-and intramolecular hydrogen bonding shown as dashed lines.

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.