2-(4,5-Dihydro-1H-imidazol-2-yl)pyridine

In the molecule of the title compound, C8H9N3, a new imidazoline derivative, the six- and five-membered rings are slightly twisted away from each other, forming a dihedral angle of 7.96 (15)°. In the crystal structure, neighbouring molecules are linked together by intermolecular N—H⋯N hydrogen bonds into extended one-dimensional chains along the a axis. The pyridine N atom is in close proximity to a carbon-bound H atom of the imidazoline ring, with an H⋯N distance of 2.70 Å, which is slightly shorter than the sum of the van der Waals radii of these atoms (2.75 Å). The crystal structure is further stabilized by intermolecular C—H⋯π and π–π interactions (centroid-to-centroid distance 3.853 Å).

In the molecule of the title compound, C 8 H 9 N 3 , a new imidazoline derivative, the six-and five-membered rings are slightly twisted away from each other, forming a dihedral angle of 7.96 (15) . In the crystal structure, neighbouring molecules are linked together by intermolecular N-HÁ Á ÁN hydrogen bonds into extended one-dimensional chains along the a axis. The pyridine N atom is in close proximity to a carbon-bound H atom of the imidazoline ring, with an HÁ Á ÁN distance of 2.70 Å , which is slightly shorter than the sum of the van der Waals radii of these atoms (2.75 Å ). The crystal structure is further stabilized by intermolecular C-HÁ Á Á and interactions (centroid-to-centroid distance 3.853 Å ).

Comment
Imidazoline derivatives are of great importance because they exhibit significant biological and pharmacological activities, such as antihypertensive (Blancafort, 1978), antihyperglycemic (Chan, 1993), antidepressant (Vizi, 1986), antihypercholesterolemic (Li et al., 1996) and anti-inflammatory (Ueno et al., 1995) properties. These compounds are also used as catalysts and synthetic intermediates in some organic reactions (Corey & Grogan, 1999). With regard to these important applications of imidazolines, we report here the crystal structure of the title compound.
In the title compound ( Fig. 1), bond lengths (Allen et al., 1987) and angles are within the normal ranges and are comparable with those in related structures (Stibrany et al., 2004;Kia et al., 2008Kia et al., , 2009a. The molecule is almost planar, with a maximum deviation from the mean plane of the molecule for atom N1: 0.106 (2) Å. The six-and five-membered rings are twisted from each other, forming a dihedral angle of 7.96 (15)°. Atom H1 of the imidazoline ring is in close proximity to atom N3 of the pyridine ring, with a distance of 2.70 Å [N3···H1], which is shorter than the sum of the van der Waals radii of these atoms (2.75 Å). In the crystal structure, neighbouring molecules are linked together by intermolecular N-H···N hydrogen bonds into one-dimensional extended chains along the a axis (Table 1, Fig. 2). The crystal structure is further stabilized by intermolecular C-H···π [Cg1 is the centroid of the N3/C4-C8 pyridine ring] and π-π interactions [Cg1···Cg2 = 3.853 Å and Cg2 is the centroid of the N1/C1/C2/N2/C3 ring].

Experimental
The synthetic method was based on previous work (Stibrany et al., 2004), except that 10 mmol of 2-cyanopyridine and 40 mmol of ethylenediamine were used. Single crystals suitable for X-ray diffraction were obtained by evaporation of a methanol solution at room temperature.

Refinement
The N-bound H atom was located in a Fourier difference map and refined freely ( Table 1). The other H atoms were positioned geometrically and refined with a riding approximation model; C-H = 0.95-0.99 Å and U iso (H) = 1.2U eq (C). Fig. 1. The molecular structure of the title compound, with atom labels. Displacement ellipsoids are drawn at the 50% probability level. H atoms are shown as spheres of arbitrary radius.

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K. 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.