Rhodium, the most expensive among precious metals costs about $3,000 per ounce. It is lighter than platinum and rarer than gold. It is also the most reflective element on the periodic table and can be found in searchlights, dental mirrors, and giant microscopes known as synchotrons.

The silvery white substance is prized as a potent, long-lasting catalyst and is used to concoct antifreeze, detergents and other industrial chemicals as well to make automotive catalytic converters, which cut down on air pollution.

On the other hand, a more common compound, hydroquinone is a pale organic crystal critical for many biological processes as well as the manufacture of everything from skin bleaching creams to high-performance plastics.

A team of Brown University chemists headed by Dr. Dwight Sweigart, combined these two materials (rhodium and hydroquinone) creating a new class of molecules called rhodium quinones that have potential important applications for the pharmaceutical, chemical and energy industries.

"This mixture has marvelous properties," Sweigart said. "Rhodium quinones are very fast and efficient catalysts. They also have pores, or channels, that act like a sponge, giving them the ability to store gases. The secret is rhodium. It's the Superman of elements."

The research team published the results of this study in several journals: Journal of the american chemical society, Angewandte Chemie, and the British journal Chemical Communications. In the articles, the research team outlined the potential of rhodium quinones:

• Catalysis - Rhodium quinones are highly effective catalysts for so-called carbon-carbon coupling reactions. These reactions are essential to make drugs for cancer, depression and other diseases. Rhodium catalysts promise a conceptual advance over current production systems by boosting the amount of end product and by making new drugs possible. Sweigart is currently working with William Trenkle, an assistant professor of chemistry at Brown, and graduate student Julia Barkin to use the compounds to make drugs for asthma, depression and other conditions. Through Brown, the pair filed preliminary patents on the use of rhodium quinones as catalysts.


• Synthesis - Rhodium quinones can also be used to make a new class of organolithium reagents. These compounds are used to make a wide variety of industrial chemicals, such as polymers and plastics, and are among the most important reagents available for the synthesis of new materials. The rhodium quinone-based class of organolithiums promises to improve these reagents by allowing the incorporation of active transition metals.


• Storage - Energy experts hope that hydrogen will eventually replace fossil fuels as a clean source of power. The promise: Convert the gas to electricity, leaving water as the only byproduct. But to create this "hydrogen economy," major hurdles must be overcome to make, transport and store hydrogen. Sweigart and his team have shown that rhodium quinones, in a solid state, feature channels suitable for storage of hydrogen and other gases, and might be used in fuel cells to generate electricity.

[News and Photo Source: Brown University]