“Rim‐Differentiated” Pillararenes

A “rim‐differentiated” pillar[6]arene (RD‐P[6]) was obtained successfully, with the assistance of a dimeric silver trifluoroacetate template, among eight different constitutional isomers in a direct and regioselective manner. The solid‐state conformation of this macrocycle could switch from the 1,3,5‐alternate to a truly rim‐differentiated one upon guest inclusion. This highly symmetric RD‐P[6] not only hosts metal‐containing molecules inside its cavity, but also can form a pillar[6]arene‐C60 adduct through co‐crystallization on account of donor‐acceptor interactions. The development of synthetic strategies to desymmetrize pillararenes offers new opportunities for engineering complex molecular architectures and organic electronic materials.Dedicated to Sir Fraser Stoddart on the occasion of his 80th birthday