A twin-axial[5]pseudorotaxane based on cucurbit[8]uril and a-cyclodextrin

A twin-axial hetero[5]pseudorotaxane was constructed based on 1-hexyl-4,4′-bipyridinium guest 1 and cucurbit[8]uril (CB[8]) and α-cyclodextrin (α-CD). In its structure, CB[8] included two bipyridinium units to realize the twin-axial mode, and the hexyl chain was threaded into the cavity of α-CD. The [5]pseudorotaxane contains two types of macrocyclic hosts while the single axial and twin axial modes co-exist in its structure. The transformation of [5]pseudorotaxane could be realized by the addition of acid and 2,6-dihydroxynaphthalene (HN).