A Versatile Molecular Trap Built from Hydrogen-Bonded Tiles

• Published in: Science (American Association for the Advancement of Science) Vol. 333; no. 6041; pp. 415 - 416
• Main Author: Lauher, Joseph W.
• Format: Journal Article
• Language: English
• Published: Washington American Association for the Advancement of Science 22-07-2011; The American Association for the Advancement of Science
• Subjects: Anions; Biophysics; Bottles; Cations; Geometric shapes; Hydrogen bonds; Ions; Molecular biology; Molecular structure; Molecules; PERSPECTIVES; Polyhedrons; Tiles
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1209090

A molecular host structure accommodates a wide range of guests that are selected on size alone.
A molecule trapped in a cage—more benignly referred to as a “host-guest” complex—is a bit like a ship in a bottle. Somehow, the molecule got into the cage, and it is not always clear how that happened. Some preformed cages are simply filled with small molecules, as illustrated by molecules diffusing into a zeolite chamber. Some molecules template their own cage, like the polyhedral water clathrates that trap the methane of methane ice. The cage and its contents may self-assemble like the virus proteins around an RNA or DNA core. No one has designed a synthetic molecular cage with the elegance of a virus, but chemists are getting closer (
1
–
3
). On page 436 of this issue, Liu
et al.
(
4
) report a supramolecular cage of 20 separate ions that reliably self-assemble to trap a wide variety of guests of varying charge and composition. Most fascinating, the cage “forces” the formation of previously unknown metal-halogen clusters.