4-[4-(1H-Imidazol-4-yl)phenyl]-1H-imidazole

In the molecule of the title compound, C12H10N4, the two imidazole substituents are related by inversion symmetry and each forms a dihedral angle of 25.02 (8)° with the benzene ring. In the crystal, molecules are linked through N—H⋯N hydrogen bonds, forming cyclic units [graph-set R 4 4(28)], which generate a layered structure extending across (011).

In the molecule of the title compound, C 12 H 10 N 4 , the two imidazole substituents are related by inversion symmetry and each forms a dihedral angle of 25.02 (8) with the benzene ring. In the crystal, molecules are linked through N-HÁ Á ÁN hydrogen bonds, forming cyclic units [graph-set R 4 4 (28)], which generate a layered structure extending across (011).
Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL and local programs. Intense interest in the chemistry of metal-organic frameworks stems from their intriguing structural features and potential applications in catalysis, adsorption, luminescence, etc. The title compound C 12 H 10 N 4 was designed and synthesized to enable the construction of metal-organic frameworks because of its versatile coordination modes in respect to metal complexation. In the structure of this compound ( Fig. 1), the molecule has inversion symmetry with the two imidazole moieties rotated slightly out of the plane of the benzene ring [dihedral angle, 25.02 (8)°]. In the crystal, the molecules are linked through N-H···N hydrogen bonds (Table 1), forming inter-associated cyclic units [graph set R 4 4 (28)] which generate a two-dimensional layered structure extending across (011) (Fig. 2).

Experimental
The title compound was synthesized according to literature methods (Petersen, 1950;Huisman, 1997;Have, 1997). A single crystal suitable for the X-ray diffraction study was obtained serendipitously in an attempt to synthesize a La III complex. A mixture of 5-(4-(1H-imidazol-5-yl)phenyl)-1H-imidazole and lanthanum(III) nitrate hexahydrate in water was subjected to hydrothermal conditions at 85 °C for three days and then cooled to room temperature to give colorless crystals of the title compound.

Refinement
The hydrogen atom on the N atom was located in a difference-Fourier map and refined isotropically. The other H atoms were positioned with idealized geometry (C-H = 0.93 Å) and allowed to ride, with U iso (H) = 1.2 U eq (C).

Figure 2
The two-dimensional layered structure of the title compound viewed down a. 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.