5-Hydroxy-2-nitrobenzaldehyde thiosemicarbazone (HNBATSC)

The asymmetric unit of the title compound, C8H8N4O3S, consists of two independent molecules. Each molecule is approximately planar with dihedral angles of 8.71 (3) and 1.50 (2)° between the aromatic ring and the thiosemicarbazide moiety while the NO2 group makes dihedral angles of 29.27 (3) and 17.78 (3)° with the benzene ring. In the crystal, the molecules are linked by N—H⋯S, O—H⋯O and N—H⋯O hydrogen bonds, forming two-dimensional networks parallel to (100).

The asymmetric unit of the title compound, C 8 H 8 N 4 O 3 S, consists of two independent molecules. Each molecule is approximately planar with dihedral angles of 8.71 (3) and 1.50 (2) between the aromatic ring and the thiosemicarbazide moiety while the NO 2 group makes dihedral angles of 29.27 (3) and 17.78 (3) with the benzene ring. In the crystal, the molecules are linked by N-HÁ Á ÁS, O-HÁ Á ÁO and N-HÁ Á ÁO hydrogen bonds, forming two-dimensional networks parallel to (100).
We reported here the synthesis and structural characterization of a Schiff base, 5-hydroxy-2-nitrobenzaldehydethiosemicarbazone ( Fig. 1). Due to the presence of potential hydrogen donor sites in the molecule, supramolecular hydrogen bonding interactions in the domain of thiosemicarbazones are observed. Intermolecular N-H···S interactions through R 2 2 (8) synthons result in the formation of 1D chains (Fig. 2). These 1D chains, with the aid of O-H···O interactions, form 2D corrugated sheets (Fig.3).

Experimental
5-Hydroxy-2-nitrobenzaldehydethiosemicarbazone (0.33 g, 2 mmol) and thiosemicarbazide (0.18 g, 2 mmol) were separately dissolved in 20 ml of ethanol and subsequently they were mixed. The resulting mixture (40 ml) was refluxed for 5 hrs. The precipitate, formed during this time, was filtered and washed with a small amount of ethanol. The purity of the product HNBATSC was checked by TLC. Finally HNBATSC was dissolved in acetonitrile and then slowly it was evaporated for the removal of acetonitrile to obtain white crystals.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 1.

Figure 1
ORTEP view of one of the independent molecules of the title compound. Thermal ellipsoids are at the 50% probability level.  Combination of O-H···O and N-H···S interactions leading to the formation of two-dimensional corrugated sheet. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.28 e Å −3 Δρ min = −0.33 e Å −3 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq S1 0.47754 (18