(E)-N'-(4-Hy-droxy-benzyl-idene)-3-nitro-benzohydrazide.

The mol-ecule of the title compound, C(14)H(11)N(3)O(4), assumes an E conformation about the C=N double bond. The benzene rings form a dihedral angle of 3.9 (2)°. The crystal structure is stabilized by N-H⋯O, O-H⋯N, O-H⋯O and C-H⋯O hydrogen bonds, forming layers parallel to (101). In addition, intra-layer π-π stacking inter-actions [centroid-centroid distance = 3.635 (2) Å] are observed.

2-Fluoro-N'-[(2-hydroxynaphthalen-1-yl)methylidene]benzohydrazide.

In the title mol-ecule, C(18)H(13)FN(2)O(2), the hy-droxy group is involved in an intra-molecular O-H⋯N hydrogen bond. The naphthyl ring system and the benzene ring form a dihedral angle of 31.0 (2)°. In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into chains propagating in [101].

2-Bromo-4-chloro-6-(cyclo-hexyl-imino-meth-yl)phenol.

The title compound, C(13)H(15)BrClNO, was prepared by the condensation of equimolar quanti-ties of 3-bromo-5-chloro-salicyl-aldehyde with cyclo-hexyl-amine in methanol. There is an intra-molecular O-H⋯N hydrogen bond in the mol-ecule. The cyclo-hexyl ring adopts a chair conformation.

N'-[(2-Methoxynaphthalen-1-yl)methyl-idene]-4-methyl-benzohydrazide.

In the title compound, C(20)H(18)N(2)O(2), the mean planes of the naphthyl system and the benzene ring form a dihedral angle of 88.48 (10)°. In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into C(4) chains, which propagate along the b-axis direction.