2-[(E)-(Naphthalen-2-ylimino)methyl]-4-(trifluoromethoxy)phenol

In the title compound, C18H12F3NO2, the planes of the benzene ring and the naphthalene system form a dihedral angle of 47.21 (3)°. The hydroxy group is involved in an intramolecular O—H⋯N hydrogen bond. In the crystal, weak C—H⋯O and C—H⋯F interactions link the molecules related by translations along the c and a axes, respectively, into sheets.

In the title compound, C 18 H 12 F 3 NO 2 , the planes of the benzene ring and the naphthalene system form a dihedral angle of 47.21 (3) . The hydroxy group is involved in an intramolecular O-HÁ Á ÁN hydrogen bond. In the crystal, weak C-HÁ Á ÁO and C-HÁ Á ÁF interactions link the molecules related by translations along the c and a axes, respectively, into sheets.   Table 1 Hydrogen-bond geometry (Å , ). There are two types of intramolecular hydrogen bonds in Schiff bases, which may be stabilized in keto-amine (N-H···O hydrogen bond) or phenol-imine (N···H-O hydrogen bond) tautomeric forms (Hadjoudis et al., 1987). Herewith we present the title compound (I), which exhibits the phenol-imine tautomeric form ( The molecules are linked into sheets by a combination of C-H···O and C-H···F interactions ( Table 1). The atom C10 in the reference molecule at (x, y, z) acts as a hydrogen-bond donor, via H10, to atom O1 in the molecule at (x, y, z + 1), so forming a C(8) chain running parallel to the [001] direction. Similarly, atom C5 in the molecule at (x, y, z) acts as a hydrogen-bond donor, via H5, to atom F2 in the molecule at (x + 1, y, z), so forming a C(14) chain running parallel to the [100] direction. The combination of the C(8) and C(14) chains generates a chain edge-fused R 5 5 (36) rings running parallel to the ac plane ( Fig.2)

Experimental
The title compound, (I), was prepared by reflux a mixture of a solution containing 2-hydroxy-5-(trifluoromethoxy)benzaldehyde (0.045 g 0.23 mmol) in 20 ml e thanol and a solution containing 2-Naphthyamine (0.033 g 0.23 mmol) in 20 ml e thanol. The reaction mixture was stirred for 1 hunder reflux. The crystals of (I) suitable for X-ray analysis were obtained from ethylalcohol by slow evaporation (yield % 68; m.p.369-371 K).

Refinement
The H1 atom was located in a difference map, and isotropically refined with restraint of O-H=0.82 (2) Å. All other H atoms were placed in calculated positions and constrained to ride on their parents atoms, with C-H=0.93 Å and U iso (H)=1.2U eq (C).  (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figure 1
The molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability. Dashed line denotes hydrogen bond.

Figure 2
A portion of the crystal packing showing hydrogen bonds as dashed lines.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 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.