(E)-2-[(1H-Imidazol-4-yl)methylidene]hydrazinecarbothioamide monohydrate

In the title compound, C5H7N5S·H2O, the main molecule is approximately planar, with a maximum deviation from the mean plane through the non-H atoms of 0.1478 (12) Å for the amine N atom. In the crystal, the components are connected via N—H⋯O, N—H⋯S and O—H⋯N hydrogen bonds, forming a three-dimensional network.

In the title compound, C 5 H 7 N 5 SÁH 2 O, the main molecule is approximately planar, with a maximum deviation from the mean plane through the non-H atoms of 0.1478 (12) Å for the amine N atom. In the crystal, the components are connected via N-HÁ Á ÁO, N-HÁ Á ÁS and O-HÁ Á ÁN hydrogen bonds, forming a three-dimensional network.

Experimental
Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1999); software used to prepare material for publication: WinGX publication routines (Farrugia, 2012) and CRYSCAL (T. Roisnel, local program). Our interest in thiosemicarbazone derivatives stems from their wide spectrum of biological activity (Finch et al., 2000;Alomar et al. 2013). As part of our study of thiosemicarbazone derivatives, we report herein the crystal structure of the title compound (I). The molecular structure of (I) is shown in Fig. 1. The molecule is approximately planar and the maximum deviation from the least squares plane through the 11 non-hydrogen atoms is -0.1478 (12) Å for N1. The bond angles suggest sp 2 hybridization for the C and N atoms which contributes to the planarity of the molecule. The crystal packing is stabilized by intermolecular N-H···O and N-H···S hydrogen bonds ( Fig. 2 and Table 1) forming a threedimensional network.

Experimental
All the chemicals were purchased from Merck and were used as received. An equimolar amount of thiosemicarbazide 10 mmol (0.91 g) and imidazolecarboxaldehyde 10 mmol (0.96 g) were dissolved in a mixture of ethanol and water (30 ml, 50%) and refluxed for 5 h in the presence of a catalytic amount of glacial acetic acid. Yellow crystals suitable for X-ray analysis were obtained after slow evaporation of the solution.

Refinement
H atoms bonded to C atoms were placed in calculated positions with C-H = 0.95 Å and refined in a riding-model approximation with U iso (H) = 1.2U eq (C). The H atoms bonded to O and N atoms were refined independently with fixed isotropic displacement parameters.

Figure 2
Part of the crystal structure with hydrogen bonds shown as dashed lines. Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.