4-[(E)-(4-Ethoxyphenyl)iminomethyl]phenol

In the title compound, C15H15NO2, the dihedral angle between the benzene rings is 52.04 (5)° and the molecule has an E conformation about the central C=N bond. In the crystal, molecules are connected by O—H⋯N hydrogen bonds, forming zigzag chains along the b axis. The crystal packing also features weak C—H⋯O interactions.

The molecule of (1) (Fig. 1) has an E conformation about the central C=N bond and the C=N and C-N bond lengths of 1.2853 (45) and 1.4250 (14) Å agree well with the corresponding distances in other Schiff bases (Akkurt et al., 2008;Özek et al., 2010;Khalaji et al., 2008Khalaji et al., , 2009Fejfarová et al., 2010). The dihedral angle between the two benzene rings is 52.04 (5)°. The ethoxy group is almost coplanar with the adjacent ring [dihedral angle 3.51 (12)°]. The molecules are connected by intermolecular O-H···N hydrogen bonds, forming zigzag chains along the b axis (Fig. 2). The crystal structure is further stabilized by intermolecular C-H···O hydrogen bonds.

Experimental
To a stirring solution of the 4-hydroxybenzaldehyde (0.2 mmol, in 5 ml of methanol) was added 4-ethoxyaniline (0.2 mmol) in 10 ml of methanol and the mixture was stirred for 1 h in air at 323 K and was then left at room temperature for several days without disturbance yielding suitable crystals of 1 that subsequently were filtered off and washed with Et2O.

Refinement
The hydroxyl hydrogen atom was found in difference Fourier maps and its coordinates were refined. All other hydrogen atoms were calculated geometrically and refined as riding on their parent atoms. The methyl H atoms were allowed to rotate freely about the adjacent C-C bond. The displacement coefficients of hydrogen atoms U iso (H) were set to 1.5U eq (C, O) for the methyl-and hydroxyl-groups and to to 1.2U eq (C) for the CH-and CH2-groups.

Figure 2
Hydrogen-bonded chain propagating along the b axis. Hydrogen bonds are drawn as dashed lines.

Special details
Experimental. Absorption correction: CrysAlis PRO (Agilent, 2011). Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. Refinement. The refinement was carried out against all reflections. The conventional R-factor is always based on F. The goodness of fit as well as the weighted R-factor are based on F and F 2 for refinement carried out on F and F 2 , respectively. The threshold expression is used only for calculating R-factors etc. and it is not relevant to the choice of reflections for refinement. The program used for refinement, Jana2006, uses the weighting scheme based on the experimental expectations, see _refine_ls_weighting_details, that does not force S to be one. Therefore the values of S are usually larger than the ones from the SHELX program.