2-Hydroxyimino-1-phenylethanone thiosemicarbazone monohydrate

In the title thiosemicarbazone derivative, C9H10N4OS·H2O, intramolecular N—H⋯N hydrogen bonds result in the formation of two nearly coplanar five- and six-membered rings, which are also almost coplanar with the adjacent phenyl ring. The oxime group has an E configuration and is involved in intermolecular O—H⋯O hydrogen bonding as a donor. In the crystal structure, intramolecular O—H⋯S and N—H⋯N and intermolecular O—H⋯O and N—H⋯S hydrogen bonds generate edge-fused R 2 2(8) and R 4 1(11) ring motifs. The hydrogen-bonded motifs are linked to each other to form a three-dimensional supramolecular network.

In the title thiosemicarbazone derivative, C 9 H 10 N 4 OSÁH 2 O, intramolecular N-HÁ Á ÁN hydrogen bonds result in the formation of two nearly coplanar five-and six-membered rings, which are also almost coplanar with the adjacent phenyl ring. The oxime group has an E configuration and is involved in intermolecular O-HÁ Á ÁO hydrogen bonding as a donor. In the crystal structure, intramolecular O-HÁ Á ÁS and N-HÁ Á ÁN and intermolecular O-HÁ Á ÁO and N-HÁ Á ÁS hydrogen bonds generate edge-fused R 2 2 (8) and R 4 1 (11) ring motifs. The hydrogen-bonded motifs are linked to each other to form a three-dimensional supramolecular network.

Comment
Thiosemicarbazones are derivatives of carbonyl compounds and they have a wide range of biological activities, depending on the parent aldehyde or ketone (Lukevics et al., 1995;Liberta & West, 1992). Some of the thiosemicarbazone derivatives have antitumour (Hagenbach & Gysin, 1952), antiviral (Jones et al., 1965), antileukaemic (Brockman & Thomson, 1956 and antimalarial (Klayman et al., 1979) activities. Thus, some of them have been used as drugs and have the ability to form complexes (Petering & van Giesen, 1966).
Oxime and dioxime derivatives are very important compounds in the chemical industry and medicine (Sevagapandian et al., 2000). They have a broad pharmacological activity spectrum, encompassing antibacterial, antidepressant and antifungal activities (Forman, 1964;Holan et al., 1984;Balsamo et al., 1990). The oxime (-C=N-OH) moiety is potentially ambidentate, with possibilities of coordination through nitrogen and/or oxygen atoms. It is a functional group that has not been extensively explored in crystal engineering. In the solid state, oximes are usually associated via O-H···N hydrogen bonds of length 2.8 Å.
Oxime groups possess stronger hydrogen-bonding capabilities than alcohols, phenols, and carboxylic acids (Marsman et al., 1999), in which intermolecular hydrogen bonding combines moderate strength and directionality (Karle et al., 1996) in linking molecules to form supramolecular structures; this has received considerable attention with respect to directional noncovalent intermolecular interactions (Etter et al., 1990).
In the crystal structure, intramolecular O-H···S and N-H···N and intermolecular O-H···O and N-H···S hydrogen bonds (Table 1) generate edge-fused R 2 2 (8) and R 4 1 (11) ring motifs (Fig. 2) (Bernstein et al., 1995). The hydrogen bonded motifs are linked to each other to form a three dimensional network (Fig. 3). The intra-and intermolecular hydrogen bonds seem to be effective in the stabilization of the crystal structure.

Experimental
The title compound was prepared according to the literature method (El-Shazly et al., 2005). 2-Isonitrosoacetophenone (149 mg, 1 mmol) was reacted with thiosemicarbazide (91 mg, 1 mmol) in ethanol-water mixture (1:1) by refluxing for 24 h. Then, a few drops of glacial acetic acid were added. The formed precipitate was filtered and recrystallized from ethanol to obtain yellow crystals (yield: 155 mg, 70%).   Fig. 1. The molecular structure of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

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 > 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.