(E)-4-{2-[(4-Chlorophenyl)iminomethyl]phenoxy}phthalonitrile

In the title compound, C21H12ClN3O, the phenoxy ring makes dihedral angles of 51.42 (5) and 65.01 (6)°, respectively, with the chlorophenyl and phthalonitrile rings. In the crystal structure, the molecules are interlinked through weak C—H⋯N and C—H⋯π contacts, and π–π stacking interactions via crystallographic inversion centres form a three-dimensional network. The distance between the centroids of the phthalonitrile rings is 3.9104 (11)Å, with a slippage between the rings of 1.626 Å and a perpendicular distance between the rings of 3.556 Å.

In the title compound, C 21 H 12 ClN 3 O, the phenoxy ring makes dihedral angles of 51.42 (5) and 65.01 (6) , respectively, with the chlorophenyl and phthalonitrile rings. In the crystal structure, the molecules are interlinked through weak C-HÁ Á ÁN and C-HÁ Á Á contacts, andstacking interactions via crystallographic inversion centres form a three-dimensional network. The distance between the centroids of the phthalonitrile rings is 3.9104 (11)Å , with a slippage between the rings of 1.626 Å and a perpendicular distance between the rings of 3.556 Å .

Experimental
The molecule is not planar, the dihedral angle between the phthalonitrile moiety and the ring B(C19 -C14) being 65.01 (6)°.
The unit cell of the structure of (I) (Fig. 2) shows an intermolecular π-π contact between the two symmetry related phthalonitrile rings of neighbouring molecules. The centre of gravity Cg1 of the ring C1-C6 has a perpendicular distance The distance between the ring centroids is 3.9104 (11) Å, with a slippage between the rings of 1.626 Å. Furthermore, the molecules are linked through weak intermolecular C-H···N contacts to form chains along the a axis (Fig. 2). These chains are connected via inversion related π-π interactions given above, and together with C-H···π contacts (Table 1) a three-dimensional network is formed. Cg3 is the centroid of the chlorophenyl ring C16 -C21.

Experimental
To a solution of Salicylaldehyde (0.5 g, 4.09 mmol) in DMF was added potasium carbonato (1.12 g, 8.18 mmol). The mixture was stirred for 30 min under N2. 4-Nitrophtalonitrile (0.71 g, 4.09 mmol) solution in DMF was added. The mixture was stirred for 48 h at 323 K under N2 and poured into ice-water (150 g). The product 2-(3,4-Dicyanophenoxy) benzaldehyde was filtered off and washed with water. The title compound (I) was prepared by reflux a mixture of a solution containing 2-(3,4-Dicyanophenoxy) benzaldehyde (0.5 g 2.016 mmol) in 20 ml e thanol and a solution containing 2-Chloroaniline (0.257 g 2.016 mmol) in 20 ml e thanol. The reaction mixture was stirred for 1 h under reflux. The crystals of the title compound were obtained from ethylalcohol by slow evaporation (yield % 51; m.p.409-411 K).

Refinement
The H atom bonded to C15 was refined freely. All other H atoms were placed in calculated positions and constrained to ride on their parent atoms, with C-H = 0.93-0.97 Å and U iso (H) = 1.2 U eq (C) or 1.5U eq (methyl C).
supplementary materials sup-2 Figures Fig. 1. The molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.