Concise Synthesis of Molecular Hyperboloids by Oligomeric Macrocyclization of Octagonal Molecules

Molecular hyperboloids were designed and synthesized. The synthesis was achieved by development of oligomeric macrocyclization of an octagonal molecule with a saddle shape. The saddle-shaped molecule, that is, [8]cyclo-meta-phenylene ([8]CMP), was decorated with two linkers for the oligomeric macrocyclization and was synthetically assembled by Ni-mediated Yamamoto coupling. Three congeners of the molecular hyperboloids (2mer-4mer) were obtained, and 2mer and 3mer were subjected to X-ray crystallographic analysis. Crystal structures revealed nanometer-sized hyperboloidal structures with 96 pi and 144 pi electrons, which also possessed nanopores on the curved molecular structures. Structures of [8]CMP cores of the molecular hyperboloids were compared with those of saddle-shaped phenine [8]circulene with a negative Gauss curvature to confirm their structural resemblance, which suggests further explorations of expanded networks of molecular hyperboloids.

Automated summary

Molecular hyperboloids with nanometer-sized structures and nanopores were successfully synthesized using oligomeric macrocyclization of [8]CMP molecule with two linkers. X-ray crystallographic analysis confirmed the structures of the obtained hyperboloids and revealed their resemblance to saddle-shaped phenine. This study suggests potential for exploring expanded networks of molecular hyperboloids.