1-[2-(2,5-Dichlorobenzyloxy)-2-phenylethyl]-1H-benzotriazole

In the title molecule, C21H17Cl2N3O, the benzotriazole ring is oriented at dihedral angles of 48.72 (6) and 62.94 (5)°, respectively, to the phenyl and benzene rings and the dihedral angle between the phenyl and benzene rings is 88.95 (6)°. In the crystal, weak C—H⋯N hydrogen bonds link the molecules into chains. π–π contacts between the triazole and benzene rings [centroid–centroid distance = 3.678 (1) Å] and a weak C—H⋯π interaction are also observed.

In the molecule of the title compound ( Fig. 1), the bond lengths and angles are generally within normal ranges. The planar benzotriazole ring [B (N1-N3/C9-C14)] is oriented with respect to the phenyl [A (C2-C7)] and benzene [C (C16-C21)] rings at dihedral angles of A/B = 48.72 (6) and B/C = 62.94 (5) °. The dihedral angle between phenyl and benzene rings is A/C = 88.95 (6)°. Atom C8 is -0.017 (2) Å away from the plane of the benzotriazole ring and atom C1 is 0.069 (2) Å away from the plane of the phenyl ring, while atoms O1 and C15 are -0.052 (1) and 0.010 (2) Å away from the plane of the benzene ring.
Adding methanol (5 ml) reaction was stopped. After evaporation of the solvent, dichloromethane was added to the reaction mixture and extracted with water. Then, the organic phase was separated, dried, filtered and evaporated. The precipitate formed was purified by column chromatography using chloroform and crystallized from iso-propanol to obtain colorless crystals suitable for X-ray analysis (yield; 231 mg, 69%).

Refinement
H atoms were positioned geometrically with C-H = 0.98, 0.93 and 0.97 Å for methine, aromatic and methylene H, respectively, and constrained to ride on their parent atoms, with U iso (H) = 1.2U eq (C). Fig. 1. The molecular structure of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

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.