2-(3-Nitrophenyl)-4,5-diphenyl-1H-imidazol-3-ium chloride

The title compound, C21H16N3O2 +·Cl−, contains two organic cations with similar conformation and two chloride ions in the asymmetric unit. The imidazole and benzene rings are twisted with respect to each other [dihedral angles of 24.05 (16), 24.31 (16) and 50.38 (13) in one cation and 27.70 (15), 25.07 (16) and 45.86 (14)° in the other]. The crystal packing is stabilized by N—H⋯Cl hydrogen bonds, forming an infinite one-dimensional chain parallel to the c axis.


2-
Imidazole derivatives have found wide range of applications in coordination chemistry because of their multiple coordination modes as ligands to metal ions and for the construction of novel metal-organic frameworks (Huang, et al. 2008;Fu, et al. 2008;Dai & Fu 2008). We report here the crystal structure of the title compound, di-2-(3'-nitrophenyl)-4,5-diphenyl- The title compound contains two organic cation with similar conformation and two Clions in the asymmetric unit (

Experimental
Under nitrogen protection, benzil (20 mmol), 3-nitrobenzaldehyde (20 mmol) and amine acetate (50 mmol) were added in a flask. The mixture was stirred at 110 °C for 20 h in the solution of HAC (60 ml). The resulting solution was poured into ice water (200 ml), white solid was obtained after adding NaOH (6 mol/L) till PH=7, then filtered and washed with distilled water. The crude product was recrystallized with the solution of ethanol (150 ml) and hydrochloric acid (5 ml) to yield colorless block-like crystals, suitable for X-ray analysis.

Refinement
All H atoms attached to C and N atoms were fixed geometrically and treated as riding with C-H = 0.93 Å (aromatic) and N-H = 0.86 Å with U iso (H) =1.2Ueq(C or N).

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