4-(1H-Tetrazol-5-yl)benzene-1,3-diol

In the title compound, C7H6N4O2, rings are almost coplanar, the dihedral angle between them being 8.45 (13)°. An intramolecular N—H⋯O hydrogen bond occurs. In the crystal, the molecules are linked by O—H⋯N and N—H⋯O hydrogen bonds into a three-dimensional network.


4-(1H-Tetrazol-5-yl)benzene-1,3-diol Youngjo Kim Comment
The similar structure of the title compound with two tetrazolylbenzenediol molecules per asymmetric unit together with three water molecules was reported in the literature (Gallardo et al., 1995). In this compound, the two tetrazolylbenzendiol are linked through a hydrogen-bonded network to water molecules, forming layers extending along the face of the unit cell (Gallardo et al., 1995). Herein, we report the related X-ray structure of the title compound (I) with eight tetrazolylbenzenediol molecules in unit cell and only one molecule in the asymmetric unit without any solvents. The title compound (I) could be isolated in more than 80% yield via the previously reported method (Meyer et al., 1998). Like the structure of related compound (Gallardo et al., 1995), the phenyl ring and the tetrazole ring of each molecule in the asymmetric unit are coplanar ( Fig. 1), with the dihedral angle between the benzene and tetrazole rings of 8.45 (13)°. They are connected by a network of intermolecular hydrogen bonds (Fig. 2).

Experimental
The title compound could be synthesized by the previously reported method (Meyer et al., 1998). Crystal of the title compound suitable for X-ray analysis were grown in ethanol by slow evaporation.

Refinement
All H atoms were placed in geometrically calculated positions and refined using a riding model with C-H = 0.93, O-H = 0.82 and N-H = 0.89 with U iso (H) = 1.2Ueq(C), U iso (H) = 1.5Ueq(O) and U iso (H) = 1.4Ueq(N).

4-(1H-Tetrazol-5-yl)benzene-1,3-diol
Crystal data 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 N1 0.86210 (12