1-Methyl-4-(1-methyl-1H-benzimidazol-2-yl)pyridinium iodide

The cation of the title compound, C14H14N3 +·I−, is non-planar, the dihedral angle between the benzimidazole and the 1-methylpyridinium planes being 37.4 (2)°. The crystal structure is stabilized by weak π–π stacking interactions, the centroid–centroid distances between 1-methylimidazole and benzimidazole planes being 3.678 (4) Å.

The cation of the title compound, C 14 H 14 N 3 + ÁI À , is non-planar, the dihedral angle between the benzimidazole and the 1methylpyridinium planes being 37.4 (2) . The crystal structure is stabilized by weakstacking interactions, the centroidcentroid distances between 1-methylimidazole and benzimidazole planes being 3.678 (4) Å .

Related literature
Imidazole and its derivatives are a very important kind of heterocyclic compounds with N-donor atoms, therefore they can be excellent organic ligands to generate various complexes (Huang et al., 2004). Owing to its biological activities such as antimicrobial, antifungal (Pawar et al., 2004), anticancer (Demirayak et al., 2002, and so on, benzimidazoles have also received much attention. The construction of new member of this family is an important direction in the development of modern coordination chemistry and biological chemistry. We report here the synthesis and crystal structure of the title compound. The molecular structure is shown in Fig. 1. The cation of (I) is non-planar, the dihedral angle between the benzimidazolyl plane and the N-methylpyridinium plane is 37.4 (2)°. The crystal structure is stabilized by π-π [Cg1: N2-C7-N3-C13-C8; Cg2(i): C8/C13, code symmetry: (i) -x+2, -y+1, -z] stacking interaction, the distance centroid-centroid between these planes is 3.678 (4) Å. The crystal packing also exhibits a weak intermolecular C-H···I interaction.

Experimental
Metallic sodium (0.25 g, 10.8 mmol) was dissolved in the stirred anhydrous ethanol(10 ml) under an atmosphere of nitrogen.
Then added 2-(4-pyridinyl)-1H-benzimidazole (1.95 g, 10 mmol), dry actone (150 ml) and methyl iodide(1.24 ml, 20 mmol) in the above solution. The reaction mixture was refluxed for 24 h. When the reaction stopped and the mixture were cooled to room temperature, the solution were removed under decompression. Then the residue recrystallized from water twice to obtain the single crystals (3.0 g, 8.66 mmol).

Refinement
All H atoms were fixed geometrically and were treated as riding on their parent C atoms, with C-H distances in the range of 0.93-0.96 Å, and with U iso (H) = 1.2U eq (parent atom), or U iso (H) = 1.5U eq (C methyl ). Fig. 1. The asymmetric unit of the title compound with atom labels. Displacement ellipsoids were drawn at the 30% probability level.

Special details
Geometry. Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) Rms deviation of fitted atoms = 0.0100 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 Rfactors(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.