2-[(E)-(2,4-Dichlorobenzylidene)amino]isoindoline-1,3-dione

In the title compound, C15H8Cl2N2O2, the molecule adopts an E configuration about the central C=N double bond. The isoindoline ring is essentially planar, with a maximum deviation of 0.019 (2) Å. The dihedral angle between the isoindoline ring and the dichloro-substituted benzene ring is 6.54 (9)°. An intramolecular C—H⋯O hydrogen bond occurs. A short Cl⋯Cl contact of 3.4027 (9) Å is present in the crystal structure. The crystal packing is further stabilized by weak C—H⋯π interactions.

In the title compound, C 15 H 8 Cl 2 N 2 O 2 , the molecule adopts an E configuration about the central C N double bond. The isoindoline ring is essentially planar, with a maximum deviation of 0.019 (2) Å . The dihedral angle between the isoindoline ring and the dichloro-substituted benzene ring is 6.54 (9) . An intramolecular C-HÁ Á ÁO hydrogen bond occurs. A short ClÁ Á ÁCl contact of 3.4027 (9) Å is present in the crystal structure. The crystal packing is further stabilized by weak C-HÁ Á Á interactions.

D-HÁ
In the title compound ( Fig. 1), the molecule adopts an E configuration about the central C7═N1 double bond. The isoindoline ring is essentially planar, with a maximum deviation of 0.019 (2) Å for atom C8. The dihedral angle between the isoindoline ring and the dichloro-substituted phenyl ring is 6.54 (9)°. An intramolecular C-H···O hydrogen bond which generates an S(6) ring motif and a short Cl···Cl contact of 3.4027 (9) Å are present in the crystal structure. The crystal packing ( Fig. 2) is further stabilized by a weak C-H···π (Table 1) interactions involving the C1-C6 ring.

Experimental
A mixture of 2-amino-1,3-isoindolinedione (6.15 mmol, 1.0 g) and 2,4-dichloro benzaldehyde (6.15 mmol, 1.08 g) was dissolved in an appropriate amount of ethanol-glacial acetic acid (2:1 v/v). The mixture was refluxed on water-bath for 0.5 hr to give a white colour precipitate. The solution was cooled at room temperature, filtered off, washed with ethanol and dried. The isolated product was recrystallized from chloroform-methanol (1:1 v/v)to get the new Schiff base in 80% yield.

Refinement
All hydrogen atoms were positioned geometrically [C-H = 0.93 Å] and were refined using a riding model, with U iso (H) = 1.2 U eq (C). Fig. 1. The asymmetric unit of the title compound, showing 30% probability displacement ellipsoids. The intramolecular C-H···O hydrogen bond is shown as a dashed line.

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 supplementary materials sup-3 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 R-factors based on ALL data will be even larger.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )