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.