Syntheses of copillar[5]arenes by co-oligomerization of different monomers.

Three copillar[5]arenes, pillar[5]arenes containing different repeating units, were successfully prepared by co-oligomerization of different monomers. It was demonstrated that the yields of pillararenes could be improved by using hydroquinone diethers with appropriate aliphatic chain lengths. Pseudorotaxane-type threaded structures were obtained in the solid state by the inclusion of an n-hexane molecule into the cavity of either a homopillar[5]arene, a pillar[5]arene containing only one repeating unit, or a copillar[5]arene.