N′-Diphenyl­methyl­ene-2-hydroxy­benzohydrazide

The title compound, C20H16N2O2, was synthesized by the reaction of 2-hydroxy­benzohydrazide with diphenyl­methanone. The dihedral angle between the phenyl rings is 76.28 (11)°. The amino H atom is involved in an intra­molecular N—H⋯O hydrogen bond. In the crystal structure, the hydr­oxy groups and carbonyl O atoms form inter­molecular O—H⋯O hydrogen bonds, which link the mol­ecules into chains running along the b axis

1-(2-Chloro­benzyl­idene)-2-(2,4-dinitro­phen­yl)hydrazine

In the title compound, C13H9ClN4O4, there are two crystallographically independent mol­ecules in the asymmetric unit, which have very similar conformations. The C=N—N angles in each independent mol­ecule are 115.0 (2) and 116.6 (2)°, which are significantly smaller than the ideal value of 120° expected for sp 2-hybridized N atoms. This is probably a consequence of repulsion between the nitro­gen lone pairs and the adjacent N—N bonds. Two bifurcated intra­molecular N—H⋯O hydrogen bonds help to establish the mol­ecular conformation and consolidate the crystal packing

2-(1H-1,2,3-Benzotriazol-1-yl)-N′-(2-chloro­benzyl­idene)acetohydrazide

In the title compound, C15H12ClN5O, the mean planes of the benzotriazole and chloro­phenyl fragments form a dihedral angle of 70.8 (1)°. In the crystal, mol­ecules are linked into infinite chains along the a axis by N—H⋯O hydrogen bonds. Weak inter­molecular C—H⋯N hydrogen bonds further link these chains into layers parallel to the ab plane. The crystal studied was a racemic twin