Self-Assembly of Pentaphenol Adducts: Formation of 3D Network and Ladder-type Supramolecular Structures in the Solid State

The interplay of strong and weak hydrogen bonds has been used to produce self-assembled architectures by the
complexation of pentaphenol 1 with the diaza compounds such as pyrazine (pyz), 4,4‘-bipyridine (bpy), trans-1,2-bis(4-pyridyl)ethylene (bpy-ethe), and 1,2-bis(4-pyridyl)ethane (bpy-etha). In all cases, the primary recognition patterns involve O−H···N and
O−H···O hydrogen bonds. The crystal structure of complex 1·pyz involves ladder structures stabilized by π···π stacking between
the benzene rings of 1 and pyz. Interpenetrating ladder architectures were observed in the crystal lattice of complex 1·bpy. A
network of cyclic cavities and ladder structures dominated the solid lattice of complexes 1·bpy-ethe and 1·bpy-etha. Both complexes
are isomorphous; they crystallize as dihydrates and also have the same space group, P1̄. In the complex 1·bpy-ethe, the existence
of C−H···π interactions involving the double bond of the ethene moiety provides additional stabilization to the three-dimensional
(3D) network structure. The formation of various supramolecular motifs from the complexes can be attributed to the 3D structure
of molecule 1 and the flexibility of the linking aza molecules in the crystal lattice.