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.含偶氮苯（azobenzene）的客体分子的反式构型可与柱[6]芳烃（pillar[6]arene）形成络合物；由于柱[6]芳烃与柱[5]芳烃（pillar[5]arene）的空腔尺寸存在差异，该客体无法与柱[5]芳烃形成络合物。该含偶氮苯客体与柱[6]芳烃所形成的主客体复合物（host–guest complex）的自发聚集行为，可通过紫外线（UV）与可见光照射实现可逆光控，从而在无规聚集体与囊泡状聚集体（vesicle-like aggregates）之间实现切换。这种基于柱[6]芳烃的光响应主客体识别基元（photoresponsive host–guest recognition motif）可在有机溶剂中正常工作，是当前广泛应用的环糊精（cyclodextrin）/偶氮苯识别基元的优良补充。