4-Iodobenzohydrazide

In the structure of the title compound, C7H7IN2O, the hydrazide group is inclined at 13.3 (3)° with respect to the benzene ring. The structure is stabilized by intermolecular N—H⋯N and N—H⋯O hydrogen bonds involving the hydrazide group, resulting in six- and ten-membered rings with R 2 2(6) and R 2 2(10) graph-set notations, respectively.

In the structure of the title compound, C 7 H 7 IN 2 O, the hydrazide group is inclined at 13.3 (3) with respect to the benzene ring. The structure is stabilized by intermolecular N-HÁ Á ÁN and N-HÁ Á ÁO hydrogen bonds involving the hydrazide group, resulting in six-and ten-membered rings with R 2 2 (6) and R 2 2 (10) graph-set notations, respectively.

Comment
The title compound and its oxovanadium(IV) complex were investigated for their α-glucosidase inhibitory and urease activities. Free hydrazide ligand was found to be inactive, whereas its oxovanadium(IV) complex was found to be a potent inhibitor of α-glucosidase (Ashiq, Ara et al., 2008) and urease (Ara et al., 2007). Continuing our studies on the enzyme inhibition behavior of the title compound, (I), and to investigate the change in its activity due to complexation with vanadium center, we have synthesized (I) and report its crystal structure in this paper. The structures of benzhydrazide (Kallel et al., 1992), para-chloro (Saraogi et al., 2002) and para-bromo (Ashiq, Jamal et al., 2008) analogues of (I) have already been reported.
The molecule of the title compound ( Fig. 1) is far from planar as is evident from the dihedral angle of 13.3 (3)° between the mean-planes of the phenyl ring (C1-C6) and the hydrazide moiety (N1/N2/O1/C7). The bond distances and bond angles in (I) are similar to the corersponding distances and angles reported in the structures quoted above. The molecules of (I) are involved in two types of hydrogen bonds involving hydrazide moiety. On one hand, the molecules lying about inversion centers form six membered rings via N1-H1A···N2 i hydrogen bonding. On the other hand, the molecules related by c-glide form ten membered rings via N2-H2A···O1 ii ; detail of the hydrogen bonding have been presented in Table 1 and depicted in Fig. 2. The six and ten membered rings represent R 2 2 (6) and R 2 2 (10) graph set patterns, respectively (Bernstein et al., 1994).

Experimental
All reagent-grade chemicals were obtained from Aldrich and Sigma Chemical companies and were used without further purification. To a solution of ethyl-4-iodobenzoate (5.5 g, 20 mmol) in 75 ml ethanol, hydrazine hydrate (5.0 ml, 100 mmol) was added. The mixture was refluxed for 5 h and a solid was obtained upon removal of the solvent by rotary evaporation.

Refinement
H-atoms bonded to N-atoms were located from a difference map and were included in the refinement at those positions (using DFIX command with N-H = 0.86 (1) Å) while the aryl H-atoms were positioned geometrically in a riding mode, with C-H = 0.93 Å; for all H-atoms, U iso = 1.2 times U eq of the parent atoms.

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 > 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.