A Diaminopillar[5]arene‐Based Macrobicyclic Molecule: Synthesis, Characterization and A Lock–Key Story.

A new macrobicyclic molecule (BC‐DAP5), consisting of a diaminopillar[5]arene cavity and a fused ring, was successfully constructed using a Grubbs metathesis reaction. Further studies indicated that BC‐DAP5 possessed a unique molecular behavior, showing a response to acid/base stimuli. In BC‐DAP5, protons (acid) acted as a lock, locking the fused ring out of the cavity (pillar[5]arene), and a base served as the key, making the fused ring switch in or out freely. Reversible control of the molecular behavior was achieved simply by adding acid and base alternately. A new macrobicyclic molecule, consisting of a diaminopillar[5]arene cavity and a fused ring, was successfully prepared through a Grubbs metathesis reaction. The molecule showed a unique molecular behavior, being responsive to acid/base stimuli. Reversible control of the molecular behavior was achieved simply by adding acid and base alternately. [ABSTRACT FROM AUTHOR]