N′-Cyclohexylidene-2-hydroxybenzohydrazide

In the title molecule, C13H16N2O2, the cyclohexylidene ring adopts a chair conformation. The intramolecular N—H⋯O hydrogen bond influences the molecular conformation: the benzene ring and the mean plane of the central C(O)NHN fragment form a dihedral angle of 4.9 (1) Å. In the crystal, intermolecular O—H⋯O hydrogen bonds link the molecules into chains propagated along [001].

In the title molecule, C 13 H 16 N 2 O 2 , the cyclohexylidene ring adopts a chair conformation. The intramolecular N-HÁ Á ÁO hydrogen bond influences the molecular conformation: the benzene ring and the mean plane of the central C(O)NHN fragment form a dihedral angle of 4.9 (1) Å . In the crystal, intermolecular O-HÁ Á ÁO hydrogen bonds link the molecules into chains propagated along [001].

Experimental
Salicyloyl hydrazide (5 mmol) and cyclohexanone (5 mmol),20 ml e nthanol were mixed in 50 ml flash. After stirring 30 min at 353 K, the mixture then cooling slowly to room temperature and affording the title compound, then recrystallized from ethanol, affording the title compound as a red crystalline solid. Elemental analysis: calculated for C 13 H 16 N 2 O 2 : C 67.22, H 6.94, N 12.06%; found: C 67.29, H 6.85, N 12.24%.

Refinement
All H atoms were placed in geometrically idealized positions (N-H 0.86 Å, O-H 0.82 Å and C-H=0.93-0.97 Å) and treated as riding on their parent atoms, with U iso (H) = 1.2-1.5U eq of the parent atom. In the absence of any significant anomalous scatterers in the molecule, 330 Friedel pairs were merged before the final refinement. Fig. 1. The molecular structure of (I) with the atomic numbering scheme and 30% probability displacement ellipsoids.

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-supplementary materials sup-3 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.