(E)-2-[1-(1-Benzothiophen-3-yl)ethylidene]hydrazinecarbothioamide methanol hemisolvate

The asymmetric unit of the title compound, C11H11N3S2·0.5CH4O, contains four thiosemicarbazone molecules and two methanol solvent molecules. Each hydrazinecarbothioamide molecule adopts an E configuration with respect to the C=N double bond and is stabilized by an intramolecular N—H⋯N hydrogen bond, resulting in an S(5) ring motif. In the crystal structure, an extensive network of N—H⋯O, N—H⋯N, O—H⋯S and N—H⋯S hydrogen bonds and weak C—H⋯O, C—H⋯N and C—H⋯S contacts together with an S⋯S [3.5958 (14) Å] and a C—H⋯π interaction form a three-dimensional network.

The asymmetric unit of the title compound, C 11 H 11 N 3 S 2 Á-0.5CH 4 O, contains four thiosemicarbazone molecules and two methanol solvent molecules. Each hydrazinecarbothioamide molecule adopts an E configuration with respect to the C N double bond and is stabilized by an intramolecular N-HÁ Á ÁN hydrogen bond, resulting in an S(5) ring motif. In the crystal structure, an extensive network of N-HÁ Á ÁO, N-HÁ Á ÁN, O-HÁ Á ÁS and N-HÁ Á ÁS hydrogen bonds and weak C-HÁ Á ÁO, C-HÁ Á ÁN and C-HÁ Á ÁS contacts together with an SÁ Á ÁS [3.5958 (14) Å ] and a C-HÁ Á Á interaction form a threedimensional network.
The asymmetric unit of (I) contains four molecules, labeled A-D (Figs 1-4) and two methanol solvate molecules, with the complete assemblage shown in Fig. 5. Each molecule adopts an E configuration with respect to the C=N bond and bond distances and angles are normal (Allen et al., 1987). Intramolecular N3-H···N1 hydrogen bonds (Table 1) form between each of the the NH 2 groups and the imine N atoms generating S(5) ring motifs (Bernstein et al., 1995). These contribute to the planarity of the molecules.

Experimental
A 1:1 mixture of 2-acetylbenzothiophene and thiosemicarbazide was heated under reflux in ethanol for 2 h. The solid product which separated upon cooling was filtered and recrystallized from a 1:1 mixture of acetonitrile and methanol to afford colourless, blocks of (I) in 68% yield (m.p. 483-485 K).

Refinement
The C-bound H atoms were placed geometrically (C-H = 0.95-0.98Å) and refined as riding with U iso =1.2U eq (C) of 1.5U eq (methyl C).
The N-bound H atoms were located in a difference map and refined with a distance restraint of N-H = 0.84 (1) Å, and with U iso (H) = 1.2U eq (N) (carrier).
The highest residual electron density peak is 0.07 Å from O2S and the deepest hole is 0.04Å from C2S suggesting the possibility of unresolved disorder in this methanol solvate molecule. Fig. 1. The structure of molecule A in (I) showing 50% probability displacement ellipsoids for the non-H atoms. The intramolecular N-H···N hydrogen bond is drawn as a dashed line.       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 Rfactors(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.