Self-Assembly of Tetraphenol and Its Complexes with Aromatic Diamines:  Novel Interpenetrating and Noninterpenetrating Organic Assemblies

The solid-state self-assembly of tetraphenol 1 and its complexes with 4,4‘-bipyridine (bpy), trans-1,2-bis(4-pyridyl)ethylene (bpy-ethe), and 1,2-bis(4-pyridyl)ethane (bpy-etha) is reported. Forces such as O−H···N, O−H···O and weak interactions prevalent in the structures promote the formation of interpenetrating and noninterpenetrating supramolecular assemblies. The crystal structure of tetraphenol 1 is characterized by the formation of hydrogen-bonded eight-membered cyclic structures. A diamondoid network was observed in the crystal lattice of 1·bpy with tetraphenol as the node and 4,4‘-bipyridine as the spacer. The resulting superadamantane framework is filled via self-clathration to give an 8-fold interpenetrating network. 1·bpy-ethe self-assembled into a stepladder-type arrangement with the bpy-ethe linkers forming the rungs of the ladder. In the lattice of complex 1·bpy-etha, ladder-type and cyclic structures organized adjacent to each other and the water molecules present inside the lattice stabilized the assembly through hydrogen bonding. No interpenetrating networks were observed in the lattices of 1·bpy-ethe and 1·bpy-etha. The C₃ symmetry of tetraphenol 1, orientation of the -OH groups, and the rigidity or the flexibility of the linking aza compounds together with the interplay of hydrogen bonds and packing forces facilitate the formation of stable supramolecular architectures.