Editorial: New Macrocycles and Their Supramolecular Perspectives

After more than half a century from the discovery of crown-ethers by Pedersen, macrocyclic hosts continue to be protagonists in supramolecular chemistry. Their peculiar structures make them ideal candidates to perform supramolecular functions such as catalysis, molecular and biomolecular recognition, sensing, self-assembly, and threading to give interpenetrated architectures. In addition, thanks to their synthetic versatility, the macrocycles are useful platforms for the design of more elaborated structures for the self-assembly of supramolecular polymers and for applications in biomimetic chemistry. These aspects have stimulated the creativeness of the scientists that in this way started imagining novel macrocyclic structures with the aim to perform ever more advanced supramolecular functions and properties. Thus, in the last years, in addition to the most innovative aspects regarding the “old” macrocycles, much attention has also been focused on the synthesis of new macrocycles. These studies have led to the discovery of novel classes of hosts such as pillararenes, cycloparaphenylene, biphenarenes, oxatubarene, large resorcinarenes, and a wide class of heteracalixarenes, coronarenes, which have found applications in several areas of supramolecular chemistr