1-Mesitylmethyl-1Hbenzotriazole 3-oxide

In the title compound, C16H17N3O, the benzotriazole ring forms a dihedral angle of 77.25 (6)° with the phenyl ring. The benzotriazole ring is essentially planar with a maximum deviation of 0.012 (19) Å. Weak intermolecular C—H⋯O hydrogen bonds form R 2 2(10) motifs. The crystal packing is consolidated by π—π interactions with centroid–centroid distances of 3.5994 (12) Å together with very weak C—H⋯π interactions.

In the title compound, C 16 H 17 N 3 O, the benzotriazole ring forms a dihedral angle of 77.25 (6) with the phenyl ring. The benzotriazole ring is essentially planar with a maximum deviation of 0.012 (19) Å . Weak intermolecular C-HÁ Á ÁO hydrogen bonds form R 2 2 (10) motifs. The crystal packing is consolidated byinteractions with centroid-centroid distances of 3.5994 (12) Å together with very weak C-HÁ Á Á interactions.

Experimental
A mixture of mono(bromomethyl)mesitylene (0.213 g, 1 mmol) and sodium salt of 1-Hydroxybenzotriazole (0.157,1 mmol) in ethanol (20 ml) was heated at 333 K with stirring for 30 min. The compound formed was filtered off, and dried. The compound was dissolved in ethanol and chloroform (1: 1v/v) and allowed to undergo slow evaporation. Colourless block shaped crystals were obtained after a week.

Refinement
All the H atoms were positioned geometrically (C-H=0.95 Å (aromatic); C-H=0.98 (methyl) or C-H=0.99 Å (methylene) and refined using a riding model with, U iso (H)=1.2U equ (C, methylene) and 1.5U equ (C methyl ). A rotating group model was used for the methyl groups.

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. Symmetry codes: (i) −x+1, −y+1, −z; (ii) −x+1, y−1/2, −z+1/2; (iii) −x+2, y−1/2, −z+1/2.