N'-(2,6-Difluoro-benzyl-idene)pyridine-4-carbohydrazide

N'-[(E)-4-Hy-droxy-benzyl-idene]-2-(naph-tha-len-2-yl-oxy)acetohydrazide

The asymmetric unit of the title compound, C₁₉H₁₆N₂O₃, contains two independent mol­ecules in which the dihedral angles between the naphthalene ring system and the benzene ring are 10.0 (1) and 35.3 (1)°. In the crystal, mol­ecules are linked by N—H⋯O and O—H⋯O hydrogen bonds, forming a two-dimensional framework parallel to (001). Weak C—H⋯O and C—H⋯N hydrogen bonds complete a three-dimensional network.

N'-[(E)-3-Chloro-2-fluoro-benzyl-idene]-6-methyl-nicotinohydrazide monohydrate

The title compound, C₁₄H₁₁ClFN₃O·H₂O, exists in an E conformation with respect to the N=C bond. The pyridine ring forms a dihedral angle of 5.00 (9)° with the benzene ring. In the crystal, the ketone O atom accepts one O—H⋯O and one C—H⋯O hydrogen bond, the water O atom accepts one N—H⋯O and two C—H⋯O hydrogen bonds and the pyridine N atom accepts one O—H⋯N hydrogen bond, forming layers parallel to the ab plane.

N'-[(E)-4-Bromo-benzyl-idene]-1-benzofuran-2-carbohydrazide monohydrate

The title compound, C₁₆H₁₁BrN₂O₂·H₂O, exists in a trans conformation with respect to the N=C bond [1.2815 (14) Å] and the benzofuran ring system forms a dihedral angle of 2.96 (5)° with the benzene ring. In the crystal, the ketone O atom accepts two O—H⋯O and one C—H⋯O hydrogen bond, and the water O atom accepts an N—H⋯O inter­action. Together, these lead to infinite layers lying parallel to (100).