2-Amino-N-(2-benzyloxy-3-methoxybenzylidene)aniline

The title compound, C21H20N2O2, a Schiff base ligand, contains two independent molecules (A and B) in the asymmetric unit, with similar conformations. In molecule A, the central benzene ring forms dihedral angles of 30.79 (13) and 23.56 (13)°, respectively, with the amino and benzyl benzene rings, while in molecule B these angles are 32.30 (13) and 13.13 (12)°. The molecular structure is stabilized by intramolecular N—H⋯N and C—H⋯O hydrogen bonds. The crystal structure is stabilized by N—H⋯N hydrogen bonds and N—H⋯π and C—H⋯π interactions.

The crystal packing of the title compound is controlled by N-H···N hydrogen bonds, and N-H···π and C-H···π interactions (Table 1).
Single crystals suitable for X-ray diffraction were obtained by slow evaporation of a hexane solution at room temperature.

Refinement
Amino H atoms were located in a difference map and their positional parameters were refined with N-H distances restrained to 0.90 (1)Å. C-bound H atoms were positioned geometrically and refined using a riding model with C-H = 0.95 Å for aromatic and methyine H, 0.99 Å for methylene H, and 0.98 Å for methyl H atoms. The U iso values were constrained to be 1.5U eq of the carrier atom for methyl H atoms and 1.2U eq for the remaining H atoms. A rotating group model was used for the methyl groups. The highest peak is located at 0.60 Å from H7A and the deepest hole is located at 0.71 Å from N2A. Fig. 1. The asymmetric unit of the title compound. Displacement ellipsoids are drawn at the 30% probability level. Intramolecular interactions are shown as dashed lines.

Data collection
Bruker SMART APEXII CCD area-detector diffractometer 7737 independent reflections

Special details
Experimental. The low-temperature data was collected with the Oxford Cyrosystem Cobra low-temperature attachment.
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 R-factors based on ALL data will be even larger.