(E)-2-[(2-Ethylphenyl)iminiomethyl]-6-hydroxyphenolate

The molecule of the title compound, C15H15NO2, crystallizes in a zwitterionic form, and displays an E configuration about the C=N bond. The dihedral angle between the two aromatic rings is 5.59 (6)°. An intramolecular N—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal structure, pairs of molecules are linked into centrosymmetric R 2 2(10) dimers by pairs of O—H⋯O hydrogen bonds. Aromatic π–π interactions are observed between the benzene rings of adjacent dimers [centroid–centroid distance = 3.4808 (7) Å].

The molecule of the title compound, C 15 H 15 NO 2 , crystallizes in a zwitterionic form, and displays an E configuration about the C N bond. The dihedral angle between the two aromatic rings is 5.59 (6) . An intramolecular N-HÁ Á ÁO hydrogen bond generates an S(6) ring motif. In the crystal structure, pairs of molecules are linked into centrosymmetric R 2 2 (10) dimers by pairs of O-HÁ Á ÁO hydrogen bonds. Aromaticinteractions are observed between the benzene rings of adjacent dimers [centroid-centroid distance = 3.4808 (7) Å ].
Recently, the synthesis, structure and properties of Schiff base complexes have stimulated much more interest for their noteworthy contributions in pharmaceutical and medicinal activities (Sriram et al., 2006;Hao, 2009;Bedia et al., 2006).

Refinement
Atom H1 was located in a difference map and refined freely. The remaining H atoms were placed in calculated positions and constrained to ride on their parents atoms, with C-H = 0.93-0.97 Å , O-H = 0.82 Å, N-H = 0.92 Å and U iso (H) = 1.2U eq (C) and 1.5U eq (O,C methyl ). Fig. 1. The molecular structure of the title compound, with the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

Special details
Experimental. 196 frames, detector distance = 80 mm The beam size = 0.8 mm.
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 > σ(F 2 ) is used only for calculating Rfactors(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.