1,3-Bis(3-phenylpropyl)-1H-benzimidazol-3-ium-2-carbodithioate

The title compound, C26H26N2S2, was synthesized from bis[1,3-bis(3-phenylpropyl)benzimidazolidine-2-ylidene] and CS2 in toluene. The molecular structure is composed of a benzimidazole ring system with two phenylpropyl substituents and a dithiocarboxylate group in the 2-position. The benzimidazole unit is essentially planar, with a maximum atomic deviation of 0.008 (2) Å, and makes dihedral angles of 72.72 (10) and 27.62 (12)°, with the two phenyl rings. The dihedral angle between the two phenyl rings is 55.98 (15)°. The molecular packing is stabilized by a C—H⋯S intermolecular hydrogen-bonding interaction and a C—H⋯π interaction between a benzene H atom and the phenyl ring of a neighbouring molecule.

The title compound, C 26 H 26 N 2 S 2 , was synthesized from bis[1,3-bis(3-phenylpropyl)benzimidazolidine-2-ylidene] and CS 2 in toluene. The molecular structure is composed of a benzimidazole ring system with two phenylpropyl substituents and a dithiocarboxylate group in the 2-position. The benzimidazole unit is essentially planar, with a maximum atomic deviation of 0.008 (2) Å , and makes dihedral angles of 72.72 (10) and 27.62 (12) , with the two phenyl rings. The dihedral angle between the two phenyl rings is 55.98 (15) . The molecular packing is stabilized by a C-HÁ Á ÁS intermolecular hydrogen-bonding interaction and a C-HÁ Á Á interaction between a benzene H atom and the phenyl ring of a neighbouring molecule.

Comment
Benzimidazole derivatives consistute an important class of heterocyclic compounds for their biological activities. They also are an important source for electron-rich olefin synthesis. Electron rich olefins are an important research subject for their versatile reactions. Since electron rich olefins are powerful nucleophilic compounds, they have been used as reducing agents, and are a source of carbine transation metal complexes and formylating agents for the proton active compounds (Hahn & Jahnke, 2008;Lappert, 2005). They are readily converted by carbon disulfide to red coloured stable dithioquaternary salts. (Winberg & Coffman,1965). Electron rich olefins have also been used as catalysts for cyloin type C-C coupling reactions.
The objective of this study was to elucidate the crystal structure of the title compound and to compare it with those of related benzimidazole derivatives reported previously (Akkurt et al., 2004;Öztürk et al., 2004;Akkurt et al., 2005).
The ORTEP diagram of the title molecule with numbering scheme is shown in Fig. 1. The molecular structure of the title compound is composed of a benzimidazole ring with two phenylpropyl substituents and a dithiocarboxylate group in the 2-position. In the title molecule the C-S bonds are nearly equal in length. The N1-C7 and N2-C7 bond lengths in the benzimidazole ring agree well with several related benzimidazole derivatives (Öztürk et al., 2003;Akkurt et al., 2004). The benzimidazole unit (N1/N2/C1-C7) is essentially, with a maximum deviation from the least-squares plane of 0.008 (2) Å for C6. The benzimidazole ring makes dihedral angles of 72.72 (10) and 27.62 (12)°, with the two phenyl rings (C12-C17) and (C21-C26), respectively. The dihedral angle between the two phenyl rings is 55.98 (15)°.

Refinement
H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93 and C-H = 0.97 Å, and with U iso (H) = 1.2U eq (C). Fig. 1. View of the title molecule, with the atom numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 30% probability level.