Host-Guest Chemistry in Layer-by-Layer Assemblies Containing Calix[n]arenes and Cucurbit[n]urils: A Review

This review provides an overview of the synthesis of layer-by-layer (LbL) assemblies containing calix[n]arene (CA[n]) and cucurbit[n]uril (CB[n]) and their applications. LbL assemblies, such as thin films and microcapsules, containing selective binding sites have attracted considerable attention because of their potential use in separation and purification, sensors for ions and molecules, and controlled release. CA[n]-containing LbL films have been prepared using sulfonated CA[n] and cationic polymers to construct chemical sensors and molecular containers. CA[n]-containing LbL films deposited on the surface of a porous support are useful as ion-selective membranes that exhibit selective permeability to monovalent ions over multivalent ions. CB[n]s have been used as molecular glues for the construction of LbL films and microcapsules by taking advantage of the strong affinity of CB[n]s to aromatic compounds. CB[n]s form a stable 1:1:1 ternary complex with electron-rich and electron-deficient molecules in LbL films to stabilize the assemblies. CB[n]-containing LbL films can also be deposited on the surfaces of micro templates and nanopore membranes to construct microcapsules for controlled release and nanochannels for selective ion transport, respectively.