Chemists identify organic molecules that mimic metals

Apr 19, 2007

A limitation in using hydrogen as a fuel in hydrogen-powered vehicles is the difficulty involved in storing it in a cost-effective and convenient manner. While it is possible to store hydrogen using metals, the resulting products often can be prohibitively expensive and cause environmental problems.

Chemists at UC Riverside now offer a possible solution. A class of carbenes – molecules that have unusual, highly reactive carbon atoms – can mimic, to some extent, the behavior of metals, the chemists have found. Called cyclic alkyl amino carbenes or CAACs, these organic molecules, the researchers report, could be used to develop carbon-based systems for storing hydrogen.

Study results appear in the April 20 issue of Science.

In their experiments, the researchers found that the CAACs can split hydrogen under extremely mild conditions, a behavior that has long been seen in metals reacting with hydrogen.

"The mode of action of these organic molecules, however, is totally different from that of metals," said Guy Bertrand, a distinguished professor of chemistry who led the research. "Moreover, the CAACs are able to split ammonia as well – an extremely difficult task for metals."

Bertrand explained that such a splitting of ammonia, under certain conditions, can pave the way for transforming abundant and inexpensive ammonia into useful amino compounds used to make pharmaceuticals and bulk industrial materials. "This is one of the top challenges for the 21st century," he said.

According to the UCR research team, the metal-mimicking carbenes offer another low-cost and low-toxicity benefit: Scientists now may be able to use non-metallic catalysts for a reaction, called "hydrogenation reaction," which plays a critical role in the food, petrochemical and pharmaceutical industries.

In their study, the researchers exposed a solution of CAACs to both gaseous hydrogen and liquid ammonia. "We used nuclear magnetic resonance spectroscopy to analyze the products," said Guido Frey, the first author of the research paper and a postdoctoral fellow, supported by the Alexander von Humboldt Foundation, in Bertrand’s lab. "And we used single crystal X-ray diffraction analysis to confirm the structure of the products."

A carbene is a molecule that has a carbon atom with six electrons instead of the usual eight. Because of the electron deficiency, carbenes are highly reactive and usually unstable in nature.

Source: University of California - Riverside

Explore further: Scientists identify tissue-degrading enzyme in white-nose syndrome

Related Stories

Recommended for you

Video: Why are avocados so awesome?

11 hours ago

Whether they're in a big bowl of guacamole for your Cinco de Mayo festivities or scooped on top of your salad, avocados enjoy a special place in our hearts and stomachs. On top of being tasty, avocados are ...

Study describes revolutionary method of making RNAs

11 hours ago

A biochemist from The University of Texas Health Science Center at San Antonio is a co-author on a paper in Nature that describes a new, more efficient method of making ribonucleic acids (RNAs).

For batteries, one material does it all

17 hours ago

Engineers at the University of Maryland have created a battery that is made entirely out of one material, which can both move electricity and store it.

Wood-polymer composite furniture with low flammability

18 hours ago

Wood is a popular material in interior design, but its water absorbency limits its use in bathrooms, where natural wood easily becomes discolored or moldy. Fraunhofer scientists and partners have developed ...

User comments : 0

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.