Host-guest binding motifs based on hyperbranched polymers.

Host-guest chemistry involves the binding of a substrate molecule (guest) to a receptor molecule (host). Various molecules, including crown ethers, cryptands, cyclophanes, calixarenes, cyclodextrins, and so on, have been used as molecular hosts. However, only limited small molecules or simple ions can be encapsulated in these hosts. Fortunately, as a class of unique host molecules, hyperbranched polymers (HBPs) can bind to numerous guests through topological entrapment, electrostatic bonding, hydrogen bonding or hydrophobic interactions in the core, at the branching points or at the periphery. Hence, hyperbranched polymeric hosts have received increasing attention in the past few decades because of their specific and unique properties. This review briefly summarizes these unique properties related to HBPs serving as hosts. In addition, HBP-based host-guest systems will be classified according to the types of guests encapsulated. Besides, the corresponding applications will be presented as well. We hope to motivate an increased understanding of molecular recognition in HBPs, and further facilitate the optimization of future host-guest systems.