3-(1H-Tetrazol-5-yl)benzoic acid

The title compound, C8H6N4O2, is a difunctional compound with a carboxylate and a tetrazole residue. In the crystal structure, molecules are linked into two-dimensional sheets by intermolecular N—H⋯O and O—H⋯N hydrogen bonds.

The title compound, C 8 H 6 N 4 O 2 , is a difunctional compound with a carboxylate and a tetrazole residue. In the crystal structure, molecules are linked into two-dimensional sheets by intermolecular N-HÁ Á ÁO and O-HÁ Á ÁN hydrogen bonds.

Comment
Tetrazoles have been extensively investigated in organic synthetic chemistry for several decades due to the fact that they have wide ranging applications in pharmaceuticals, especially explosives, photography, information recording systems, agriculture, and as precursors to a variety of heterocycles (Chen et al. 2007;Demko et al. 2001). They have also been used as a type of important multidentate ligands in coordination chemistry. Here, we report the crystal structure of a new tetrazole, 3-(1H-tetrazol-5-yl)benzoic acid.
The title compound, C 8 H 6 N 4 O 2 , is a difunctional compound with carboxylate and tetrazole groups. The C=O distance of the carboxylate is 1.216 (2) Å, which is much shorter than the C-O distance of 1.311 (2) Å. In the tetrazole group, the N=N distance is 1.288 (2) Å, and the N-N distances are 1.343 (2) and 1.358 (2) Å, respectively. The C-N distance is 1.333 (2) Å, being close to the C=N distance of 1.325 (2) Å, which is considered to have part double-bond character. In the crystalline state, the molecules are linked to two-dimensional hydrogen-bonding networks by intermolecular N-H···O and O-H···N hydrogen bonds. The N···O distance is 2.712 (2) Å, and the O···N distance is 2.666 (2) Å.

Experimental
A mixture of 3-cyanobenzoic acid (0.147 g, 1.0 mmol), Cd(NO 3 ) 2 .6H 2 O (0.345 g, 1 mmol) and water (8 ml) was was heated in a 15-ml Teflon-lined autoclave at 160 ° for 3 days, followed by slow cooling (5 ° h-1) to room temperature. The resulting mixture was washed with water and collected. Then, the obtained solids were put into 20 ml water, and 10% Na 2 S aqueous solution was droped to the suspension liquid until that no precipitation appeared. The solution was filtered and the filtrate was acidified with 50% HCl solution until the pH value was 1.0. White products were filtered, washed with water, then dried and collected in 76.2% yield (0.145 g) based on 3-cyanobenzoic acid. Colorless block shaped crystals were collected from the filtrate after the second filtration.

Refinement
H atoms bonded to N and O atoms were located in a difference map and were freely refined. Other H atoms were positioned geometrically and refined using a riding model with C-H = 0.93 Å and with U iso (H) = 1.2.    as those based on F, and R-factors based on ALL data will be even larger.