Crystal structure of (E)-1-{[(3,5-dimethylphenyl)imino]methyl}naphthalen-2-ol

The title compound, C19H17NO, has an E conformation about the N=C bond. The molecule is relatively planar, with the benzene ring and naphthalene ring plane being inclined to one another by 4.28 (10)°. There is an intramolecular O—H⋯N hydrogen bond generating an S(6) ring motif. In the crystal, molecules are linked via C—H⋯O hydrogen bonds, forming chains propagating along [100]. Within the chains there are π–π interactions involving the benzene ring and the naphthalene ring system of an adjacent molecule [inter-centroid distance = 3.6405 (14) Å].


Related literature
For the diverse applications and biological activities of Schiff bases, see: Schiff (1864); Dutta & Das (1988); Chandra & Sangeetika (2004); Cozzi (2004). For the biological activity and optical properties of Schiff bases derived from 2-hydroxynapthaldehyde, see: Abdel-Rahman et al.  193 parameters H-atom parameters constrained Á max = 0.17 e Å À3 Á min = À0.14 e Å À3 Table 1 Hydrogen-bond geometry (Å , ). Schiff bases, known as anils, imines or azomethines, have recently received considerable attention due to their good performance in coordination chemistry, unique anti-bacterial, anti-cancer, and herbicidal applications (Schiff, 1864;Abdel-Rahman et al., 2013a,b,2014Dutta & Das,1988). Studies showed that the presence of a lone pair of electrons in an sp 2 hybridized orbital of the nitrogen atom of the azomethine group is of considerable chemical and biological importance (Chandra & Sangeetika, 2004;Cozzi, 2004). In continuation of our interest in the chemical, herbicidal and biological properties of Schiff bases we synthesized the title compound as a potential anti-bacterial agent.
The title compound, has an E conformation about the N1═C11 bond, as illustrated in Fig. 1. The molecule is relatively planar with the benzene ring (C12-C17) and the naphthalene plane (C1-C10) being inclined to one another by 4.31 (10) °. There is an intramolecular O-H···N hydrogen bond generating an S(6) ring motif (Table 1 and Fig. 1).
In the crystal, molecules are linked via C-H···O hydrogen bonds (Table 1)

S2. Synthesis and crystallization
The title compound was prepared by treating 3,5-dimethylaniline (0.38 ml, 3 mmol) in 30 ml of dry ethanol with 2-hydroxynapthaldehyde (0.52 g, 3 mmol) with vigorous stirring at 343 K for 2 h. The reaction mixture was then left to stand at room temperature for 30 min. The yellow crystals were collected and washed several times in ethanol.

S3. Refinement details
Crystal data, data collection and structure refinement details are summarized in

Figure 1
A view of the molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level. The intramolecular O-H···N hydrogen bond is shown as a dashed line (see Table 1 for details).

Figure 2
A view along the b axis of the crystal packing of the title compound. Hydrogen bonds are shown as dashed lines (see Table 1 for details). H atoms not involved in these interactions have been omitted for clarity. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.17 e Å −3 Δρ min = −0.14 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.