5-(4-Chlorobenzyl)-1H-tetrazole

In the title compound, C8H7ClN4, the phenyl and tetrazole rings are inclined at a dihedral angle of 67.52 (6)°. In the crystal, molecules are linked by an N—H⋯N hydrogen bond into a chain structure along [010]. π–π interactions with centroid–centroid distances of 3.526 (1) Å between adjacent tetrazole rings further link the chains, forming a ribbon structure.

In the title compound, C 8 H 7 ClN 4 , the phenyl and tetrazole rings are inclined at a dihedral angle of 67.52 (6) . In the crystal, molecules are linked by an N-HÁ Á ÁN hydrogen bond into a chain structure along [010].interactions with centroid-centroid distances of 3.526 (1) Å between adjacent tetrazole rings further link the chains, forming a ribbon structure.

Comment
The tetrazole has attracted considerable interesting owing to their structural characterization in coordination chemistry and the extensively application in medicinal chemistry and materials science (Zhao et al. 2008;Kitagawa et al. 2004). Here, we report the synthesis and crystal structure of the title compound.
As shown in fig.1, the benzenyl plane and tetrazole rings form a dihedral angle about 67.52 (6) ° (Fig. 1). In the crystal packing, the molecules are linked by N-H···N hydrogen bonds into a chain structure alone [010] (Fig. 2, Table 1). The π-π interactions with distances of 3.526 (1) Å (center to center) between the adjacent tetrazole rings further link them to form ribbon structure (Fig. 3).
Then, it was cooled to room temperature and the mixture was filtered. The solvent was evaporated and the residue was poured into cold water (30 ml) to give the title compound (4.32 g, 55.5 %). The crystals suitable for X-ray diffraction were obtained from 10 mL mixed solution of ethanol and water (1:1).

Refinement
The anormal reflection data (-12 3 3) have been omitted during the refinement.H atoms bound to C atoms were placed in calculated positions and treated as riding on their parent atoms, with C-H = 0.93 Å (aromatic); C-H = 0.97 Å (methylene), and with U iso (H) = 1.2U eq (C). N-bounded H atom was found from Fourier map and was refined restrainedly with N-H = 0.90 Å. Fig. 1. The molecular structure of the title compound, showing displacement ellipsoids at the 50% probability level for non-H 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 > 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.