CB7

CB7 stands for cucurbit[7]uril, a macrocyclic host molecule in the cucurbituril family. It has a pumpkin-shaped architecture composed of seven glycoluril units linked by methylene bridges. The molecule features two carbonyl-rich portals and a hydrophobic interior cavity. CB7 is highly soluble in water and remains stable under a wide range of conditions, making it a versatile scaffold for supramolecular chemistry.

CB7 binds a variety of guest molecules to form 1:1 host–guest complexes. Binding is driven by a combination of hydrophobic effects within the cavity and favorable interactions at the polar carbonyl portals, which can stabilize cationic or otherwise complementary guests. Because of this, CB7 often shows high affinities for positively charged and hydrophobic guests, with association constants commonly ranging from 10^5 to 10^12 M^-1 depending on the guest.

CB7 is widely used as a tool in host–guest chemistry and in applications such as drug solubilization and stabilization, sensing, and catalysis within confined supramolecular environments. It can modulate the activity and release profiles of guest molecules and can act as a molecular container in aqueous solutions.

CB7 can be synthesized from glycoluril derivatives and formaldehyde under acid catalysis, and it is commercially available from multiple chemical suppliers. It is part of the larger family of cucurbiturils, which also includes CB5, CB6, CB7, and CB8, differing primarily in the number of glycoluril units and cavity size.