1-(1-Benzyl-1H-benzimidazol-2-yl)ethanone

In the title compound, C16H14N2O, the benzimidazole ring system is essentially planar. The planes of the benzene rings make a dihedral angle of 85.92 (8)°. In the crystal, neighbouring molecule are connected into paris along the c axis by weak C—H⋯O interactions and the connected pairs are expanded through C—H⋯N hydrogen bonds and C—H⋯π interactions along the b axis.

In the title compound, C 16 H 14 N 2 O, the benzimidazole ring system is essentially planar. The planes of the benzene rings make a dihedral angle of 85.92 (8) . In the crystal, neighbouring molecule are connected into paris along the c axis by weak C-HÁ Á ÁO interactions and the connected pairs are expanded through C-HÁ Á ÁN hydrogen bonds and C-HÁ Á Á interactions along the b axis.  Table 1 Hydrogen-bond geometry (Å , ).

Related literature
Cg1 and Cg2 are the centroids of the C4-C9 and C20-C25 rings, respectively.

1-(1-Benzyl-1H-benzimidazol-2-yl)ethanone
Chuan-Jing Zhang, Xiu-Zhen Xu, Ning Yang, Ren-Ying Zhao and Yan-Qing Ge Comment Synthesis of nitrogen-containing heterocyclic compounds has been a subject of great interest due to the wide applications in the agrochemical and pharmaceutical fields (Ge et al.;2009, 2011. Some benzoimidazole derivatives which belong to this category exhibit interesting biological properties, such as anti-bacterial, anti-inflammatory, anti-fungal and antitumor. The title benzoimidazole(I) (Fig. 1) was synthesized in order to study its biological properties. (I) was screened for anticancer activities and found to be inactive.
We report here the crystal structure of the title compound. In the molecular structure, the 90 degree angle on alpha shows the benzene ring and the imidazole are in the same plane and the two benzene ring makes dihedral angle of 85.92 (8)°. Moreover, there exist inermolecular weak C-H···O and C-H···N hydrogen bonding, also the intermolecular face-to-face C-H···π stacking interaction.

Experimental
A mixture of 1-(1H-benzo[d]imidazol-2-yl)ethanone(0.02 mol), (chloromethyl)benzene (0.024 mol) and potassium carbonate (0.024 mol) in acetonitrile (100 ml) was heated to reflux for 5 h. The solvent was removed under reduced pressure and the product was isolated by column chromatography on silica gel (yield 85%). Crystals of (I) suitable for Xray diffraction were obtained by allowing a refluxed solution of the product in ethyl acetate (0.10 M) to cool slowly to room temperature (without temperature control) and allowing the solvent to evaporate for 12 h.

Refinement
All H atoms were placed in geometrically calculated positions and refined using a riding model with C-H = 0.97 Å (for CH 2 groups) and 0.93 Å (for aromatic protons), their isotropic displacement parameters were set to 1.2 times the equivalent displacement parameter of their parent atoms.  The molecular structure of (I), showing displacement ellipsoids drawn at the 50% probability level.

1-(1-Benzyl-1H-benzimidazol-2-yl)ethanone
Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 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.