{(E)-4-Hy­droxy-N′-[phen­yl(pyridin-2-yl-κN)methyl­idene]benzohydrazide-κ²N′,O}bis­(nitrato-κ²O,O′)copper(II)

In the title compound, [Cu(NO₃)₂(C₁₉H₁₅N₃O₂)], the coordination geometry around the Cu^II ion can be described as distorted square-pyramidal, with two N atoms and one O atom from an (E)-4-hy­droxy-N′-[phen­yl(pyridin-2-yl)methyl­ene]benzohydrazide ligand and one nitrate O atom in the basal plane and one nitrate O atom at the apical site. The other two nitrate O atoms also bind to the Cu atom with long Cu—O distances [2.607 (4) and 2.853 (5) Å]. The crystal packing is stabilized by inter­molecular N—H...O and O—H...O hydrogen bonds.

2-[((E)-2-{2-[(E)-2-Hy­droxy­benzyl­idene]hydrazinecarbon­yl}hydrazinyl­idene)meth­yl]phenol

The mol­ecule of the title compound, C₁₅H₁₄N₄O₃, is completed by the application of crystallographic twofold symmetry, with the carbonyl group lying on the rotation axis. The mol­ecule is close to planar: the greatest deviation of a torsion angle from 0° is 7.3 (2)° about the bond linking the phenol ring to the rest of the mol­ecule. An intra­molecular O—H...N(imine) hydrogen bond is formed in each half of the mol­ecule. The carbonyl O atom is anti with respect to the amine H atoms and this allows for the formation of N—H...O(hydrox­yl) hydrogen bonds in the crystal, which results in supra­molecular layers lying parallel to (100).

(E)-4-{2-[(2-Hy­droxy­naphthalen-1-yl)methyl­idene]hydrazinecarbon­yl}pyridinium nitrate

The title compound, C₁₇H₁₄N₃O₂⁺·NO₃⁻, is an aroylhydrazone-based material consisting of a 4-(hydrazinecarbon­yl)pyridinium cation and a nitrate anion. In the cation, the dihedral angle between the benzene ring and the naphthalene ring system is 2.20 (7)°. In the cation, the configuration about the C=N bond is E. There is an intra­molecular O—H...N hydrogen bond in the cation, and the supra­molecular structure is stabilized by inter­molecular N—H...O hydrogen bonds and weak C—H...O contacts between the cation and the nitrate anion.

N′-[(2Z)-4-Oxo-4-phenyl­but-2-en-2-yl]pyridine-4-carbohydrazide

There are significant twists in the title compound, C₁₆H₁₅N₃O₂, as seen in the dihedral angle between the benzene and adjacent but-2-enal group [29.26 (4)°] and between the pyridine ring and amide group [24.79 (6)°]. A twist is also evident around the hydrazine bond [the C—N—N—C torsion angle is −138.25 (13)°]. The conformation about the ethene bond is Z. An intra­molecular N—H...O hydrogen bond involving the benzoyl O atom and leading to an S(6) motif is formed. Significant delocalization of π-electron density is found in this part of the mol­ecule. In the crystal, helical supra­molecular chains aligned along the b axis and mediated by N—H...O hydrogen bonds are formed.

N′-[(E)-2-Hy­droxy-5-iodo­benzyl­idene]furan-2-carbohydrazide monohydrate

The organic mol­ecule of the title monohydrate, C₁₂H₉IN₂O₃·H₂O, features a disordered furyl ring with the major component [site occupancy = 0.575 (18)] having the carbonyl O and furyl O atoms syn, and the other conformation having these atoms anti. The mol­ecule is slightly twisted with the dihedral angle between the benzene and furyl rings being 10.3 (6)° (major component). An intra­molecular O—H...N(imine) hydrogen bond is formed. In the crystal, the water mol­ecule accepts a hydrogen bond from an amine H atom, and forms two O—H...O(carbon­yl) hydrogen bonds, thereby linking three different carbohydrazide mol­ecules. The result is a supra­molecular layer parallel to (001). The closest contacts between layers are of the type I...I, at a distance of 3.6986 (6) Å.

(E)-2-(2-Hy­droxy-5-iodo­benzyl­idene)hydrazinecarboxamide

In the title mol­ecule, C₈H₈IN₃O₂, there is an intra­molecular O—H...N hydrogen bond between the hy­droxy group and the imine N atom, which generates an S(6) ring. In the crystal, the carbonyl O atom accepts two different N—H...O hydrogen bonds, which connect mol­ecules with two R₂²(8) motifs.

(E,E)-N′-{4-[(2-Benzoyl­hydrazin-1-yl­idene)meth­yl]benzyl­idene}benzo­hydrazide

In the title compound, C₂₂H₁₈N₄O₂, the mol­ecules lie across an inversion centre. The dihedral angle between the mean planes of the central and terminal benzene rings is 66.03 (2)°. The mol­ecule displays trans and anti conformations about the C=N and N—N bonds, respectively. In the crystal, N—H...O hydrogen bonds, with the O atoms of C=O groups acting as acceptors, link the mol­ecules into a chain along [101].

(E)-4-Hy­droxy-N′-(2-hy­droxy-5-iodo­benzyl­idene)benzohydrazide methanol monosolvate

In the title compound, C₁₄H₁₁IN₂O₃·CH₄O, the dihedral angle between the benzene rings is 33.2 (3)°. The mol­ecule displays trans and anti conformations about the C=N and N—N bonds, respectively. There is an intra­molecular O—H...N(azomethine) hydrogen bond. Inter­molecular N—H...O and O—H...O hydrogen bonds consolidate mol­ecules into a three-dimensional architecture.