Functional Coordination Capsules Featuring Bent Anthracene Dimers

Abstract

This review describes our investigations into bent anthracene dimers as building blocks for various nanoarchitectures since 2008. Using these building blocks, we prepared novel polyaromatic capsules, bowls, and tubes through coordination and covalent bonds, hydrophobic effect, and π-stacking interactions. Among them, the coordinative capsule is formed by the quantitative self-assembly of metal ions and bispyridine ligands embedding the bent building block. The capsule possesses a spherical polyaromatic nanocavity, capable of binding various molecules in aqueous solutions. For example, reactive radical initiators and oligosulfurs are greatly stabilized in the cavity upon encapsulation. Biomolecules such as hydrophilic sucrose, hydrophobic androgens, and volatile monoterpenes are bound by the capsule with high selectivity. In addition, an analogous capsule, with a spheroidal cavity, displays unique binding properties toward bowl-shaped molecules. We are convinced that continued investigations will render the present capsules useful molecular nanotools for synthetic, material, and biological applications.