Pillararenes: Versatile Synthetic Receptors for Supramolecular Chemistry

In 2008 we reported a new class of macrocyclic hosts that we named "pillararenes". To date, pillar[5]arenes and pillar[6]arenes, containing five and six repeating units, respectively, have been synthesized. Pillar[5]arenes and pillar[6]arenes can accommodate 10 and 12 substituent groups, respectively. The position-selective versatile functionalization of these substituents enables the preparation of various supramolecular assemblies. Here we discuss the synthesis and selective functionalization of pillararenes. We also discuss the use of the various pillararene derivatives as components of supramolecular assemblies such as sensors, a self-inclusion complex, supramolecular dimers, polymers, an alternating polymer consisting of pillar[5]arene and pillar[ 6]arene units, systems in which pillararene shuttles along an axle, rotaxanes, polyrotaxanes, and pillar[5]arene-based bulk-materials, as well as colloidal assembly of pillararenes, biomedical applications, and hybridization with inorganic materials.