3-(1H-Imidazol-1-yl)propanenitrile

The title compound, C6H7N3, has an ethylene group connecting an imidazole ring and a –CN group. These groups are in a staggered conformation. The shortest intermolecular contact is found between the imidazole N atom and a –CH2– group of a neighboring molecule.

The title compound, C 6 H 7 N 3 , has an ethylene group connecting an imidazole ring and a -CN group. These groups are in a staggered conformation. The shortest intermolecular contact is found between the imidazole N atom and a -CH 2group of a neighboring molecule.

Comment
Ionic Liquids (ILs) are more and more attracting remarkable attention as new solvents and reaction media for organic and inorganic synthesis and catalysis in order to replace volatile organic solvents (Wasserscheid & Keim, 2000). Imidazolium based ILs have emerged as leading candidates since they have very low vapor pressures, are moisture and air stable, and are highly solvating for both molecular and ionic species. Furthermore, ILs are finding use in separation processes (Visser et al., 2001), in battery applications (Scheers et al., 2008), as electrolytes in solar cells (Wang et al., 2003), or as part of metal catalysts and magnetic liquids (Lombardo et al., 2007;Hayashi et al., 2006;Kozlova et al., 2009a;Kozlova et al., 2009b).
In this context we present the molecular and single-crystal structure of 3-(1H-imidazol-1-yl)propanenitrile, an important precursor of nitrile functionalized ILs. Although all other sources report this compound to be a liquid at room temperature, there is one single indication in the literature that it is a solid melting at 33-35 °C (Sawa & Okamura, 1969). A freshly distilled sample crystallizes spontaneously within days, forming big block-shaped colourless crystals, which are barely deliquescent and melting at 37 °C.
All the bond lengths are within the expected ranges. The molecular structure of the title compound is shown in Figure 1.
The C6-N3 bond length of 1.141 (1) Å indicates the triple-bond nitrile character. This nitrile group is connected through an ethylene group with the planar imidazolyl ring. The ethylene group has a staggered conformation with an N1-C4-C5-C6 torsion angle of -65.43 (9)°.
In the crystal the molecules are arranged in rows, such that this weak hydrogen bond is oriented approximately parallel to the crystallographic c direction. Due to the c glide plane, every second row, stacked along a is shifted by c/2. The packing diagram, Figure 3, shows this assembly. The positions of the hydrogen atoms were located from a difference Fourier map and refined isotropically. Fig. 1. Molecular structure of 3-(1H-imidazol-1-yl)propanenitrile with atom labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.   Geometric parameters (Å, °)