Chemists create molecular polyhedron

July 21, 2011
This is a scanning electron microscope image of a new material that self-assembles into a polyhedron using the attractive interactions associated with hydrogen bonds. The shapes then further organize into a crystal lattice that resembles a porous structure called zeolite, an absorbent material with many industrial uses. Credit: Michael D. Ward, New York University

Chemists have created a molecular polyhedron, a ground-breaking assembly that has the potential to impact a range of industrial and consumer products, including magnetic and optical materials.

The work, reported in the latest issue of the journal Science, was conducted by researchers at New York University's Department of Chemistry and its Molecular Design Institute and the University of Milan's Department of .

Researchers have sought to coerce to form regular polyhedra—three-dimensional objects in which each side, or face, is a polygon—but without sustained success. Archimedean solids, discovered by the ancient Greek mathematician Archimedes, have attracted considerable attention in this regard. These 13 solids are those in which each face is a regular polygon and in which around every vertex—the corner at which its geometric shapes meet—the same polygons appear in the same sequences. For instance, in a truncated tetrahedron, the pattern forming at every vertex is hexagon-hexagon-triangle. The synthesis of such structures from molecules is an intellectual challenge.

The work by the NYU and University of Milan forms a quasi-truncated octahedron, which also constitutes one of the 13 Archimedean solids. Moreover, as a , the structure has the potential to serve as a cage-like framework to trap other molecular species, which can jointly serve as building blocks for new and enhanced materials.

"We've demonstrated how to coerce molecules to assemble into a polyhedron by design," explained Michael Ward, chair of NYU's Department of Chemistry and one of the study's co-authors. "The next step will be to expand on the work by making other polyhedra using similar design principles, which can lead to new materials with unusual properties."

This image is a simplified representation of a compound (red, blue and green) nesting inside a single truncated octahedron (purple). Credit: Michael D. Ward, New York University

The research team's creation relies on a remarkably high number of —72—to assemble two kinds of hexagonal molecular tiles, four each, into a truncated octahedron, which consists of eight molecular tiles. Although chemists often use hydrogen bonds because of their versatility in building complex structures, these bonds are weaker than those holding atoms together within the molecules themselves, which often makes larger scale structures constructed with hydrogen bonds less predictable and less sustainable. The truncated octahedron discovered by the NYU team proved to be remarkably stable, however, because the hydrogen bonds are stabilized by the ionic nature of the molecules and because no other outcomes are possible. In fact, the truncated octahedra assemble further into crystals that have nanoscale pores, resembling a class of well-known compounds called zeolites, which are made from inorganic components.

Because the structure also serves as a molecular cage, it can house, or encapsulate, other molecular components, giving future chemists a vehicle for developing a range of new compounds.

Explore further: Chemists discover twisted molecules that pick their targets

Related Stories

Chemists discover twisted molecules that pick their targets

August 10, 2009

New York University chemists have discovered how to make molecules with a twist—the molecules fold in to twisted helical shapes that can accelerate selected chemical reactions. The research, reported in the latest issue ...

Liverpool scientists construct molecular 'knots'

July 20, 2010

Scientists at the University of Liverpool have constructed molecular 'knots' with dimensions of around two nanometers -- around 30,000 times smaller than the diameter of a human hair.

World-first to provide building blocks for new nano devices

November 23, 2010

( -- Scientists at The University of Nottingham have made a major breakthrough that could help shape the future of nanotechnology, by demonstrating for the first time that 3-D molecular structures can be built ...

Recommended for you

A new form of real gold, almost as light as air

November 25, 2015

Researchers at ETH Zurich have created a new type of foam made of real gold. It is the lightest form ever produced of the precious metal: a thousand times lighter than its conventional form and yet it is nearly impossible ...

Getting under the skin of a medieval mystery

November 23, 2015

A simple PVC eraser has helped an international team of scientists led by bioarchaeologists at the University of York to resolve the mystery surrounding the tissue-thin parchment used by medieval scribes to produce the first ...

Moonlighting molecules: Finding new uses for old enzymes

November 27, 2015

A collaboration between the University of Cambridge and MedImmune, the global biologics research and development arm of AstraZeneca, has led researchers to identify a potentially significant new application for a well-known ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (1) Jul 22, 2011
Zeolites are controversial lately in that the health claims of its free radical quenching effectiveness is being challenged. I think it's expensive, so I like to take Astaxanthin, which is pretty impressive when compared to conventional antioxidants.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.