N,N′-Bis[2,6-bis(1-methylethyl)phenyl]pyridine-4-carboximidamide toluene hemisolvate

A new member of the bulky N,N′-bis(2,6-diisopropylphenyl)arylamidine family is reported herein: the N,N′-bis(2,6-diisopropylphenyl)-4-pyridylamidine is a symmetrically N,N′-disubstituted arylamidine containing a 4-pyridyl substituent on the carbon atom of the N–C–N linkage and bulky 2,6-diisopropylphenyl groups on the nitrogen atoms.

In the title compound, the pyridyl ring is tilted with respect to the central N-C-N bridge at an angle of 35.9 (1) , while the bulky substituted aryl rings 1 and 2 (see scheme) are tilted by 65.2 (1) and 53.1 (1) , respectively.

Supramolecular features
In the crystal structure of 1, two different types of conventional intermolecular hydogen bonds (Table 1 and Fig. 3) (Desiraju & Steiner, 2001) can be identified, linking the discrete molecules in infinite chains along the a and c axes. A relatively strong N-H Á Á ÁN interaction exists between the amidine H1 proton and the N3 pyridyl ring atom of an adja- Intramolecular hydrogen-bonding pattern in 1. Co-crystallized solvent is omitted for clarity.

Figure 1
The molecular structure of 1, with displacement ellipsoids drawn at 50% probability level: main amidine moiety and co-crystallized toluene solvent (H atoms removed for clarity). Table 1 Hydrogen-bond geometry (Å , ). In the crystal packing, the chains of main amidine moieties (along the a axis) alternate with layers of co-crystallized toluene molecules, but no real attractive interactions were identified between the main amidine and the toluene.
Cg (py) is the centroid of the pyridyl ring. Cg (ring 2) is the centroid of the C19-C24 aryl ring.

Special details
Experimental. X-ray crystallographic data for I were collected from a single-crystal sample, which was mounted on a loop fiber. Data were collected using a Bruker Platform diffractometer, equipped with a Bruker SMART 4 K Charged-Coupled Device (CCD) Area Detector using the program APEX2 and a Nonius FR591 rotating anode equiped with a Montel 200 optics. The crystal-to-detector distance was 5.0 cm, and the data collection was carried out in 512 x 512 pixel mode. The initial unit-cell parameters were determined by a least-squares fit of the angular settings of strong reflections, collected by a 10.0 degree scan in 33 frames over four different parts of the reciprocal space (132 frames total). One complete sphere of data was collected, to better than 0.80Å resolution. 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (