Synthesis and analysis of hydroxyl substituted triptycene adducts: the competitive recognition between the hydroxyl substituted triptycenes with 4, 4 '-bipyridine and solvent molecules

A series of hydroxyl substituted triptycene adducts 1a-1b and 2a-2c were obtained, and their X-ray crystal structural studies showed that the synthesis of the adduct 1b was independent on the stoichiometries between 2,7-dihydroxytriptycene and 4,4'-bipyridine to a certain extent, while different stoichiometries between 2,7,14-trihydroxytriptycene and 4,4'-bipyridine in acetone resulted in different adducts 2b and 2c, respectively. In these adducts, the multiple non-covalent interactions including the competitive O-H center dot center dot center dot O and O-H center dot center dot center dot N hydrogen bonds between the hydroxyl substituted triptycenes with bipyridine and solvent molecules play important roles in controlling the formation of superstructures. The results presented here may be useful for the design and construction of new supramolecular materials based on polyhydroxy substituted triptycene scaffold.