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]

Abstract

The title compounds, C27H20Br2N6O4·2H2O, (I), and C30H28N6O4·[+ 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—CH2—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 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 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 Owater—H...O and Owater—H...N hydrogen bonds, forming chains along [001], and enclosing an R42(8) and two R12(5) ring motifs. The chains are linked by N—H...Npyridine 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...Npyridine 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.

Keywords

• crystal structure
• isonicotinoyl
• hydrazide
• pyridine
• amide
• hydrogen bonding
• Hirshfeld surface analysis
• supramolecular framework