A Macrocyclic Arene Derived from Pagoda[4]arene: Cavity Reshaping, Complexation with Neutral Guests, and CPL Property

A new type of macrocyclic arene P4-2D-A was conveniently synthesized by a one-step reaction from pagoda[4]arene. P4-2D-A existed as a fixed conformation with fluorescence emission arising from the π system of the anthracene unit. Moreover, P4-2D-A had a barrel-shaped, electron-rich cavity, as evidenced by electrostatic-potential maps, which enabled it to encapsulate different neutral linear guests in both solution and the solid state. Interestingly, as the alkyl chain lengthened and the terminal group became more electron withdrawing, association constants increased substantially, reflecting the deep cavity and multiple intermolecular interactions provided by P4-2D-A. Furthermore, P4-2D-A displayed stable planar chirality, and chiral HPLC afforded a clean resolution of the enantiomers. They displayed mirror-image CD signals and CPL property, suggesting potential application in chiral luminescent materials.