1-(2-Cyanoethyl)-1H-imidazole-4,5-dicarbonitrile

In the title tricyanonitrile compound, C8H5N5, the N-substituted cyanoethyl group is offset to the imidazole ring [dihedral angle = 75.41 (15)°].

Some of the reasons are for this are that the N atom plays an important role in the formation of metal complexes (Fujita et al., 1994), and that imidazole complexes show conjugate acid-base properties and good complexation coordination performance in the solid state. Some examples of imidazole complexes have been reported (Martin & Edsall, 1958). Here we report on a new imidazole compound, the polycyano-substituted imidazole, the title compound C 8 H 5 N 5 .

Experimental
A mixture of 4,5-dicyanoimidazole (1.18 g, 10 mmol) and powdered potassium hydroxide (100 mg) (as a catalyst) in acrylonitrile (20 ml) was heated at 130 °C for 3 hr in a sealed tube, after which the solution was evaporated to dryness.
The crude product obtained was recrystallized twice from acetone to give a pure blue product. Yield: 89.7%. Anal: Calcd.

Refinement
All H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms [C-H = 0.93 Å (aromatic) and 0.97 Å (methylene)], with U iso (H) = 1.2U eq (C).

Special details
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.