Rings of benzene that grip whatever fits inside them.
A cycloparaphenylene is a loop of benzene rings, the shortest possible slice of a carbon nanotube. Because the loop is curved, its inner surface is electron-rich in a way a flat aromatic never is, and it will hold a guest by CH–π contact alone.
Hyejin Kwon’s work in my lab showed these hoops binding polycyclic aromatics with no covalent chemistry at all, and binding metallocenes in a way that switches with redox state, so the hoop can be told when to let go.
Carson J. Bruns, Associate Professor, ATLAS Institute and the Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder.
Carson J. Bruns