Pillar[5]arene Derivatives Embedded with Aggregation-Induced Emission Luminogens and Their Fluorescence Regulation

Through McMurry coupling reaction, three meso-position functionalized pillar[5]arene derivatives (H-1, H-2, and H-3) have been successfully prepared by embedding aggregation-induced emission luminogens (AIEgens, diphenyldibenzofulvene (DPDBF) and tetraphenylethylene (TPE)) into the skeleton of supramolecular macrocycles. H-1, bearing [1₅ ]paracyclophane ([1₅ ]PCP) and DPDBF moiety, exhibits yellow emission and demonstrates obvious AIE effect. In order to further improve the host-guest properties of this type of structure, H-2 and H-3 are prepared by replacing the [1₅ ]PCP moiety with pillar[5]arene backbone, both of which show significant AIE effect and excellent host-guest complexation properties with pyrazine salt guest G-1 and 1,4-dicyanobutane G-2. Our findings indicate that G-1 can decrease the fluorescence intensity of the AIE macrocycles, while G-2 can increase their fluorescence intensity in solution.