N-(2-Iodophenyl)benzenecarboximidamide

The title compound, C13H11IN2, crystallizes with two independent molecules (A and B) in the asymmetric unit. The two aromatic rings are inclined to one another by 73.3 (2)° in molecule A, and by 74.4 (1)° in molecule B. In molecule A, the iodophenyl and the phenyl rings are inlclined to the N=C—N plane by 88.0 (4) and 19.0 (4)°, respectively. In molecule B the corresponding angles are 85.0 (4) and 20.7 (4)°, respectively. In the crystal, the two molecules are not parallel but have a dihedral angle between the iodophenyl rings of 8.6 (1)°, and 44.5 (2)° between the phenyl rings. The A and B molecules are linked vvia N—H⋯N hydrogen bonds to form –A–B–A–B– chains propagating along direction [100].

The title compound, C 13 H 11 IN 2 , crystallizes with two independent molecules (A and B) in the asymmetric unit. The two aromatic rings are inclined to one another by 73.3 (2) in molecule A, and by 74.4 (1) in molecule B. In molecule A, the iodophenyl and the phenyl rings are inlclined to the N C-N plane by 88.0 (4) and 19.0 (4) , respectively. In molecule B the corresponding angles are 85.0 (4) and 20.7 (4) , respectively. In the crystal, the two molecules are not parallel but have a dihedral angle between the iodophenyl rings of 8.6 (1) , and 44.5 (2) between the phenyl rings. The A and B molecules are linked vvia N-HÁ Á ÁN hydrogen bonds to form -A-B-Bchains propagating along direction [100].

Comment
Benzamidines and their derivatives have attracted our attention because of their application in the synthesis of heterocyclic compounds (Attanasi et al. 2010, Bhosale et al. 2010, Deng & Mani et al. 20109, Wang et al. 2011, Ohta et al. 2010. We report here the crystal structure of the title compound (Fig. 1).
The asymmetric unit of the title compound contains two crystallographically independent molecules (A and B).
Concerning the carbon atoms, molecule A is made up from C1 to C13 and molecule B is made up from C14 to C26. In both molecules the bond lengths and angles are generally within normal ranges. The bond lengths N1-C7 (1.293 (4) Å) and N3-C20 (1.293 (3) Å) displays double bond character, while the distances N2-C20 1.350 (5) Å and N4-C20 1.352 (5) Å are indicative of C-N single bonds. The two molecules are not parallel so that torsion angles of 8.6 (1)° between the two iodo-phenyl groups and 44.5 (2)° between both phenyl substituents, respectively, are observed. In molecule A, the planar benzene ring (C8-C13) and the iodine-substituted benzene ring (C1-C6) form a dihedral angle of 73.3 (2)°. The NH 2 group is twisted away from the plane of the adjacent benzene ring with a dihedral angle between the N-C bond of the NH 2 group and the plane of the adjacent phenyl ring of 18.5 (1)°. The amidine plane and both benzene rings are not coplanar showing dihedral angles of the amidine plane (N1/C7/N2) with respect to the iodine-substituted benzene ring (C1-C6) and the second benzene ring (C8-C13) of 88.2 (2)° and 51.0 (1)°, respectively. In molecule B, the planar benzene ring (C21-C26) and the iodine-substituted benzene ring (C14-C19) form a dihedral angle of 74.4 (1)°. The NH 2 group also is twisted away from the plane of the adjacent benzene ring with a dihedral angle between the N-C bond of the NH 2 group and the plane of the adjacent phenyl ring of 20.7 (2)°. The amidine plane in molecule B and both benzene rings are not coplanar showing dihedral angles of the amidine plane (N3/C20/N4) with respect to the iodine-substituted benzene ring (C14-C19) and the second benzene ring (C21-C26) of 95.1 (3)° and 20.7 (2)°, respectively. In the crystal structure intramolecular N-H···N (N2-H2B···N3 and N4-H4B···N1) hydrogen bonds exist (Table 1).

Experimental
The title compound was produced according to a methodology already described in the literature (Ma et al. 2011, Cortes-Salva et al. 2011): A round bottom flask (100 mL in volume) was charged with NaH (60% in mineral oil) (360 mg, 15.0 mmol, 60%, 1.5 equiv). Under a stream of nitrogen, DMSO (10 mL) was added, and the resulting suspension was cooled with an ice-water bath prior to the addition of the 2-iodo-phenylamine (11.0 mmol, 1.1 equiv) and benzonitrile (10.0 mmol). The mixture was kept at 0 ° for 50 min and then stirred at room temperature until the starting material was consumed as monitored by TLC analysis. Ice-water (50 mL) was added while maintaining vigorous stirring. When the amidine precipitated upon addition of water, the solid was filtered off and dissolved in EtOAc (20 mL). The aqueous layer was extracted with EtOAc (3 × 20 mL). The extracts were combined and washed with water (2 × 50 mL). The organic layer was dried over Na 2 SO 4 , filtered, and concentrated under reduced pressure. 7.88-7.86 (m, 2H), 7.47-7.05 (m, 5H), 7.47-7.05 (m, 2H), 4.86 (s, 2H)). The title compound was recrystallized from CH 2 Cl 2 at room temperature to give the desired crystals suitable for single-crystal X-ray diffraction.

Refinement
All H atoms were positioned geometrically and constrained to ride on their parent atoms (N-H = 0.86 Å and U iso (H) = 1.2U eq (N); C-H = 0.93 and 0.97 Å for aromatic and methylene H atoms with U iso (H) = 1.2U eq (C), respectively.

Figure 1
View of the two symmetry independent molecules of the title compound showing the atom numbering scheme and thermal ellipsoids at the 50% probability level. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.94 e Å −3 Δρ min = −1.34 e Å −3 Special details 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. 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 > 2sigma(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 Rfactors based on ALL data will be even larger.