2,2′-[(1E,1′E)-1,2-Phenylenebis(azanylylidene)bis(methanylylidene)]bis(4-bromophenol)

In the title compound, C20H14Br2N2O2, there are two intramolecular O—H...N hydrogen bonds forming S(6) ring motifs. The outer benzene rings are inclined to the central benzene ring by 39.09 (11) and 24.31 (11)°, and to one another by 37.12 (11)°. In the crystal, molecules are linked by a short Br...O contact [3.1307 (19) Å], forming zigzag chains propagating along the a-axis direction. The chains are linked by weak offset π–π interactions [intercentroid distance = 3.716 (1) Å], forming layers parallel to the ac plane

1,1′-{(1E,1′E)-[Octane-1,8-diylbis(azanylylidene)]bis(methanylylidene)}bis(naphthalen-2-ol) in the zwitterionic form

The title compound, C30H32O2N2, is formed from two units of ortho-hydroxynaphthaldehyde bridged with 1,8-diaminooctane. In the solid state, it exists as a double zwitterion. The N atoms are protonated and the C—O− bonds lengths are 1.265 (2) Å, with intramolecular N—H...O hydrogen bonds forming S(6) ring motifs. The molecule has twofold rotational symmetry, with the twofold axis bisecting the central –CH2—CH2– bond of the bridging octane chain. In the crystal, molecules are linked by N—H...O hydrogen bonds, forming chains propagating along the [-201] direction. The chains are linked via C—H...O hydrogen bonds, forming a supramolecular three-dimensional framework structure

Crystal structure of 1,1′-{(dodecane-1,12-diyl)bis[(azaniumylylidene)methanylylidene]}bis(naphthalen-2-olate)

The title compound, C34H40N2O2, exists in an extended conformation and has crystallographically imposed centrosymmetry. The crystal packing can be described as being composed of parallel layers stacked along [010]. The zwitterionic structure is stabilized by an intramolecular N—H...O hydrogen-bond interaction

1,1′-{(Hexane-1,6-diyl)bis[(azaniumylylidene)methanylylidene]}bis(naphthalen-2-olate)

The whole molecule of the title Schiff base compound, C28H28N2O2, is generated by inversion symmetry. It is formed from two units of ortho-hydroxynaphthaldehyde bridged with 1,6-diaminohexane. The N atoms are protonated and, thus, the structure is a bis-zwitterionic compound in the solid state. The zwitterion shows strong intramolecular N—H...O hydrogen bonds between the iminium N and the naphthalenolate O atoms