Supramolecular chemistry for the incorporation of multi-guest molecules into two-dimensional metal hydroxide hosts

The incorporation of functional molecules into the interlayer space of layered double hydroxide (LDH) has been extensively studied for its role in immobilization, stabilization, manipulation of the molecular configuration, and the release from the host. To create dramatically enhanced properties and achieve unexpectedly high performances, it is necessary to incorporate multi-guests as well as control the guest-guest interaction. In the present review, we have summarized the multi-guest incorporation into LDH based on the supramolecular chemistry, which provides insights into non-covalent molecular interaction through host-guest chemistry. Four well-known intercalation methods in LDH, that is, coprecipitation, ion exchange, reconstruction, and exfoliation-reassembly, are generally applied to multi-guest intercalation. Combinative methods, in which two different intercalation approaches are combined, are also summarized. The multi-guest incorporation, despite the difficulty involved in its synthesis design, could provide fine-tuned and enhanced properties that are useful for a variety of applications.