The crystal structures and Hirshfeld surface analysis of N′,N′′′-((1E,1′E)-{[methyl­enebis(­oxy)]bis­(6-bromo-3,1-phenyl­ene)}bis­(methan­ylyl­idene))bis­(isonicotinohydrazide) dihydrate and N′,N′′′-((1E,1′E)-{[butane-1,4-diylbis(­oxy)]bis­(2,1-phenyl­ene)}bis­(methan­ylyl­idene))bis­(isonicotino­hydrazide) [+ solvent]

The title compounds, C(27)H(20)Br(2)N(6)O(4)·2H(2)O, (I), and C(30)H(28)N(6)O(4)·[+ solvent], (II), both crystallize with one half-mol­ecule in the asymmetric unit. The whole mol­ecule of (I) is generated by twofold rotation symmetry, with the twofold rotation axis bis­ecting the C atom of the –O—CH(2)—O– bridge. This results in a folded or U-shaped conformation of the mol­ecule. The whole mol­ecule of (II) is generated by inversion symmetry, with the central CH(2)—CH(2) bond of the –O—(CH(2))(4)—O– bridge being located about a center of inversion. This results in a step-like conformation of the mol­ecule. 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 mol­ecules link the organic mol­ecules via O(water)—H⋯O and O(water)—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⋯N(pyridine) hydrogen bonds, forming a supra­molecular framework. There are also a number of C—H⋯O hydrogen bonds, and C—H⋯π and offset π–π inter­actions [inter­planar distance = 3.294 (1) Å] present reinforcing the framework. In the crystal of (II), mol­ecules are linked by N—H⋯N(pyridine) hydrogen bonds, forming a supra­molecular framework. Here too there are also a number of C—H⋯O hydrogen bonds present, and a C—H⋯π inter­action, 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.