1,3-Bis[(1H-benzotriazol-1-yl)methyl]-2,3-dihydro-1H-benzimidazole

In the title compound, C21H18N8, the two (benzotriazol-1-yl)methyl groups are located in an anti position with respect to the benzimidazoline moiety. The dihedral angles between the benzotriazole ring systems and the central benzimidazoline moiety are 57.03 (4) and 81.01 (3)°. The crystal packing is stabilized by two C—H⋯π interactions.

In the title compound, C 21 H 18 N 8 , the two (benzotriazol-1yl)methyl groups are located in an anti position with respect to the benzimidazoline moiety. The dihedral angles between the benzotriazole ring systems and the central benzimidazoline moiety are 57.03 (4) and 81.01 (3) . The crystal packing is stabilized by two C-HÁ Á Á interactions.   Table 1 Hydrogen-bond geometry (Å , ).

Related literature
Cg2 is the centroid of the N3-N5/C9/C10 ring and Cg4 is the centroid of the C2-C7 ring.  (Rivera et al., 2004) which after reaction with benzotriazole yielded a white powder which was monitored by GC-MS, 1 H NMR, and 13 C NMR spectra. The spectra showed the existence of the three possible isomers: 1,3-bis(benzotriazol-1-yl-methyl)-2,3-dihydrobenzimidazole (I), 1-(benzotriazol-1-yl-methyl)-2-(benzotriazol-2-yl-methyl)-2,3-dihydrobenzimidazole and 1,3-bis(benzotriazol-2-yl-methyl)-2,3-dihydrobenzimidazole as expected due to the prototropic tautomerism of benzotriazole (Elguero et al., 2000). The crystal structure of before mentionated compounds has not been reported previously. So, efforts were made to crystallize all of the isomers obtained. However, only the title compound afforded single crystals suitable for structural determination and all attempts to get appropriate crystals of others isomers were unsuccessful. The crystal structure of the title compound revealed the existence of two benzotriazolyl groups in an anti conformation with respect to the benzimidazoline moiety. This conformation is comparable to other benzimidazoline derivatives (Wang et al., 2008 andKuhl et al., 2008). Whereas the title compound was found to exist in an

Experimental
The title compound was prepared according to the reported method (Rivera et al., 2004). A suitable single-crystal (mp. 449-451 K) of the product was formed by slow evaporation of an ethyl acetate solution at room temperature.

Refinement
All hydrogen atoms were discernible in difference Fourier maps and could be refined to reasonable geometry. According to common practice H atoms attached to C atoms were nevertheless kept in ideal positions during the refinement. The C-H distances were constrained to 0.96 Å. The isotropic atomic displacement parameters of hydrogen atoms were evaluated as 1.2*U eq of the parent atom.   Refinement. The refinement was carried out against all reflections. The conventional R-factor is always based on F. The goodness of fit as well as the weighted R-factor are based on F and F 2 for refinement carried out on F and F 2 , respectively. The threshold expression is used only for calculating R-factors etc. and it is not relevant to the choice of reflections for refinement.
The program used for refinement, Jana2006, uses the weighting scheme based on the experimental expectations, see _refine_ls_weighting_details, that does not force S to be one. Therefore the values of S are usually larger than the ones from the SHELX program.