( E )-N 0-[ ( 2-Hydroxynaphthalen-1-yl )-methylidene ] nicotinohydrazide

In the molecule of the title compound, C17H13N3O2, the naphthyl ring system and the pyridine ring form a dihedral angle of 12.2 (3) . An intramolecular O—H N hydrogen bond generates a six-membered ring with an S(6) ring motif. This also contributes to the relative overall near planarity of the molecule [r.m.s. deviation of all 22 non-H atoms = 0.107 (5) Å]. In the crystal, molecules are linked through intermolecular N—H N hydrogen bonds, forming chains along the a axis.

In the molecule of the title compound, C 17 H 13 N 3 O 2 , the naphthyl ring system and the pyridine ring form a dihedral angle of 12.2 (3) . An intramolecular O-HÁ Á ÁN hydrogen bond generates a six-membered ring with an S(6) ring motif. This also contributes to the relative overall near planarity of the molecule [r.m.s. deviation of all 22 non-H atoms = 0.107 (5) Å ]. In the crystal, molecules are linked through intermolecular N-HÁ Á ÁN hydrogen bonds, forming chains along the a axis.

Comment
Considerable attention has been focused on hydrazones and their medicinal applications (Hillmer et al., 2010;Zhu et al., 2009). A study of the crystal structures of such compounds is of particular interest (Khaledi et al., 2009). As a continuation of our work on the preparation and structure of such compounds (Liu & You, 2010;Liu & Wang, 2010), we report herein the crystal structure of the title compound, a new hydrazone.
The molecular structure of the title compound is shown in Fig. 1. The dihedral angle between the C1-C10 naphthyl ring and the C13-C17/N3 pyridine ring is 12.2 (3) °. An intramolecular O1-H1···N1 hydrogen bond forms a six-membered ring, with an S(6) ring motif [ Fig. 1] and contributes to the overall planarity of the molecule (Bernstein et al., 1995). All the bond lengths are comparable to those observed in related structures (Xu et al., 2009;Shafiq et al., 2009) and those we reported previously. In the crystal structure, molecules are linked through intermolecular N2-H2···N3 hydrogen bonds (Table 1), to form chains along the a axis (Fig. 2).

Experimental
The title compound was prepared by the condensation reaction of 2-hydroxy-1-naphthaldehyde (1.0 mmol, 0.172 g) and nicotinohydrazide (1.0 mmol, 0.137 g) in methanol (50 ml) at ambient temperature. Colourless block-shaped single crystals suitable for X-ray structural determination were obtained by slow evaporation of the solution for a few days.

Refinement
H2 was located from a difference Fourier map and refined isotropically, with the N-H distance restrained to 0.90 (1) Å.
The remaining H atoms were positioned geometrically and constrained to ride on their parent atoms, with C-H distances of 0.93 Å, O-H distance of 0.82 Å, and with U iso (H) = 1.2U eq (C) and 1.5U eq (O). In the absence of significant anomalous dispersion effects, 1294 Friedel pairs were averaged. Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 30% probability level. Hydrogen atoms are shown as spheres of arbitrary radius and the intramolecular hydrogen bond is drawn as a dashed line.

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.
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 > 2sigma(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.