4-(2-Hydroxybenzylideneamino)benzonitrile

The molecule of the title compound, C14H10N2O, is nearly planar. There is a strong intramolecular O—H⋯N hydrogen bond between the imine and hydroxy groups. The configuration with respect to the C=N double bond is anti (1E).

The molecule of the title compound, C 14 H 10 N 2 O, is nearly planar. There is a strong intramolecular O-HÁ Á ÁN hydrogen bond between the imine and hydroxy groups. The configuration with respect to the C N double bond is anti (1E).

Comment
The Schiff base compounds have received considerable attention for several decades, primarily due to their importance in the development of coordination chemistry related to magnetism (Weber et al., 2007), catalysis (Chen et al., 2008) and biological process (May et al.,2004). Recently, we have reported a Schiff base compound (Xu et al., 2008). As an extention of our work on the structural characterization of Schiff base compounds, the title compound has been synthesized.
The molecule of the title compound is nearly planar, the two aromatic rings are only twisted by a dihedral angle 3.28 (18) ° ( Fig. 1), As expected, the molecule displays a trans configuration about the central C7=N1 imine double bond. Bond lengths and bond angles in the compound are within normal ranges (Allen et al., 1987). The C7=N1 bond length of 1.280 (4) Å indicates a high degree of double-bond character comparable with the corresponding bond lengths in other Schiff bases (1.280 (2) Å; Elmah et al., 1999).
A strong O-H···N intramolecular hydrogen-bond interaction is observed in the molecular structure (Table 1 ) as also found in previous reports (Xu et al., 2008;Cheng et al., 2006Cheng et al., , 2005.

Experimental
All chemicals were obtained from commercial sources and used without further purification except for salicylaldehyde which is distilled under reduced pressure before use. 4-aminobenzonitrile (1.18 g, 10 mmol) and salicylaldehyde (1.22 g, 10 mmol) were dissolved in ethanol (20 ml). The mixture was heated to reflux for 4 h, then cooled to room temperature overnight then large amounts of a yellow precipitate were formed. Yellow crystals were obtained by recrystallization from ethyl alcohol(yield: 81%  117.4, 118.6, 118.7, 119.4, 122.1, 132.8, 133.5, 134.3, 152.4, 161.2, 165.0.
Esi-MS: calcd for C 14 H 9 N 2 O -H m/z 221.24, found 221.34. Suitable single crystals of the title compound were obtained after one week by slow evaporation from an ethyl alcohol solution.

Refinement
All H atoms attached to C atoms and O atom were fixed geometrically and treated as riding with C-H = 0.93 °H (C) and O-H= 0.82 (1)Å with U iso (H) = 1.2U eq (C) or U iso (H) = 1.5U eq (O).  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.