N'-[(E)-2-Hy-droxy-5-meth-oxy-benzyl-idene]pyridine-4-carbohydrazide monohydrate

The crystal structures and Hirshfeld surface analysis of N',N'''-((1E,1'E)-{[methyl-enebis(-oxy)]bis-(6-bromo-3,1-phenyl-ene)}bis-(methan-ylyl-idene))bis-(isonicotinohydrazide) dihydrate and N',N'''-((1E,1'E)-{[butane-1,4-diylbis(-oxy)]bis-(2,1-phenyl-ene)}bis-(methan-ylyl-idene))bis-(isonicotino-hydrazide) [+ solvent]

The title compounds, C27H20Br2N6O4·2H2O, (I), and C30H28N6O4·[+ solvent], (II), both crystallize with one half-mol-ecule in the asymmetric unit. The whole mol-ecule of (I) is generated by twofold rotation symmetry, with the twofold rotation axis bis-ecting the C atom of the -O-CH2-O- bridge. This results in a folded or U-shaped conformation of the mol-ecule. The whole mol-ecule of (II) is generated by inversion symmetry, with the central CH2-CH2 bond of the -O-(CH2)4-O- bridge being located about a center of inversion. This results in a step-like conformation of the mol-ecule. The central C(=O)N-N=C regions of the isonicotinohydrazide moieties in both compounds are planar and the configuration about the imine C=N bonds is E. In compound (I), the benzene and pyridine rings are inclined to each other by 37.60 (6)°. The two symmetry-related pyridine rings are inclined to each other by 74.24 (6)°, and the two symmetry-related benzene rings by 7.69 (6)°. In compound (II), the benzene and pyridine rings are inclined to each other by 25.56 (11)°. The symmetry-related pyridine rings are parallel, as are the two symmetry-related benzene rings. In the crystal of (I), a pair of water mol-ecules link the organic mol-ecules via Owater-H⋯O and Owater-H⋯N hydrogen bonds, forming chains along [001], and enclosing an R 4 2(8) and two R 1 2(5) ring motifs. The chains are linked by N-H⋯Npyridine hydrogen bonds, forming a supra-molecular framework. There are also a number of C-H⋯O hydrogen bonds, and C-H⋯π and offset π-π inter-actions [inter-planar distance = 3.294 (1) Å] present reinforcing the framework. In the crystal of (II), mol-ecules are linked by N-H⋯Npyridine hydrogen bonds, forming a supra-molecular framework. Here too there are also a number of C-H⋯O hydrogen bonds present, and a C-H⋯π inter-action, reinforcing the framework. For compound (II), a region of disordered electron density was corrected for using the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9-18] routine in PLATON. Their formula mass and unit-cell characteristics were not taken into account during refinement.

N'-[(E)-3-Bromo-5-chloro-2-hy-droxy-benzyl-idene]furan-2-carbohydrazide

In the title compound, C12H8BrClN2O3, the furan ring makes a dihedral angle of 17.2 (2)° with the six-membered ring. An intra-molecular O-H⋯N hydrogen bond stabilizes the mol-ecular conformation. In the crystal, N-H⋯O hydrogen bonds connect the mol-ecules into chains running along the c-axis direction. The crystal packing is additionally stabilized by C-H⋯O inter-actions into a three-dimensional supramolecular architecture.

N′-{(E)-[5-(Hydroxymethyl)furan-2-yl]methylidene}pyridine-4-carbohydrazide dihydrate

In the title compound, C₁₂H₁₁N₃O₃·2H₂O, the dihedral angle formed by the planes of the pyridine and the furan rings of the organic carbohydrazide mol­ecule is 4.66 (7)°. In the crystal, these mol­ecules form stacks along the b-axis direction, neighbouring mol­ecules within each stack being related by inversion and the shortest distance between the centroids of the pyridine and furan rings being 3.714 (1) Å. Mol­ecules from neighboring stacks are linked by pairs of N—H⋯O hydrogen bonds. The water mol­ecules fill the channels between the stacks being linked by O—H⋯O hydrogen bonds into helices along [010]. Besides this, water mol­ecules are involved in O—H⋯N and O—H⋯O hydrogen bonds with the carbohydrazide mol­ecules, thus forming a three-dimensional network, augmented by weak C—H⋯O interactions.