Cucurbit[n]urils: from mechanism to structure and function

This feature article details some of the unusual recognition properties of the cucurbit[n]uril family (CB[n]) of molecular containers. It discusses the mechanism of CB[n] formation, which proceeds from glycoluril via methylene bridged glycoluril oligomers, along with descriptions of the structures and recognition properties of some kinetically stable macrocyclic intermediates along the way. These partially formed CB[n]-type receptors known as nor-seco-CB[n] display intriguing properties such as chiral recognition, homotropic allostery, and function as aldehyde reaction cucurbituril synthons.