Pillar[6]arene-Based Photoresponsive Host–Guest Complexation

The trans form of an azobenzene-containing
guest
can complex with a pillar[6]­arene, while it cannot complex with pillar[5]­arenes
due to the different cavity sizes of the pillar[6]­arene and the pillar[5]­arenes.
The spontaneous aggregation of its host–guest complex with
the pillar[6]­arene can be reversibly photocontrolled by irradiation
with UV and visible light, leading to a switch between irregular aggregates
and vesicle-like aggregates. This new pillar[6]­arene-based photoresponsive
host–guest recognition motif can work in organic solvents and
is a good supplement to the existing widely used cyclodextrin/azobenzene
recognition motif.