2-[(1H-Benzimidazol-2-yl)sulfanyl]-1-phenylethanone

The title compound, C15H12N2OS, adopts a twisted V-shape, with the S atom as the pivot. The benzimidazole ring system [maximum deviation = 0.015 (1) Å] makes a dihedral angle of 78.56 (7)° with the phenyl ring. The O atom of the ketone group is close to coplanar with its adjacent ring [O—C—C—C torsion angle = 11.0 (2)°]. In the crystal, molecules are linked by N—H⋯N hydrogen bonds into an infinite chain along [001]. The crystal packing also features a C—H⋯π interaction.

The title compound, C 15 H 12 N 2 OS, adopts a twisted V-shape, with the S atom as the pivot. The benzimidazole ring system [maximum deviation = 0.015 (1) Å ] makes a dihedral angle of 78.56 (7) with the phenyl ring. The O atom of the ketone group is close to coplanar with its adjacent ring [O-C-C-C torsion angle = 11.0 (2) ]. In the crystal, molecules are linked by N-HÁ Á ÁN hydrogen bonds into an infinite chain along [001]. The crystal packing also features a C-HÁ Á Á interaction.
In the crystal (Fig. 2), molecules are linked by N2-H1N2···N1 hydrogen bond into an infinite chain along the c-axis.

Experimental
The title compound was prepared by the reaction of 1H-benzo[d]imidazole-2-thiol and 2-bromo-1-phenylethanone in ethanol in the presence of potassium hydroxide (D′Amico et al., 1964). Colourless needles were crystallised from ethanol solution.

Refinement
The atom H1N2 was located in a difference fourier map and refined freely [N2-H1N2 = 0.880 (19) Å]. The remaining H atoms were positioned geometrically [C-H = 0.93 and 0.97 Å] and refined using a riding model with U iso (H) = 1.2U eq (C).

Figure 2
The crystal packing of the title compound. The dashed lines represent the hydrogen bonds. For clarity sake, hydrogen atoms not involved in hydrogen bonding have been omitted.  (Cosier & Glazer, 1986) operating at 100.0 (1) K. 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.