Accelerated reaction

Chemists at the University of California, Riverside have synthesised a new class of carbene molecules  that is expected to have wide applications in the pharmaceutical industry.

Called Cyclic Alkyl Amino Carbenes, or CAACs, the molecules attach themselves to metals, such as palladium, to form catalysts that allow chemical transformations otherwise considered impossible. The carbenes modulate the properties of the metals to which they are bound and can facilitate and speed up reactions involving their use.

A carbene molecule 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.

"The new carbenes we have prepared in the laboratory are such that they protect the metals to which they bind, making the metal catalysts more stable," said Guy Bertrand, Distinguished Professor of Chemistry at the University. What is more, just mild temperatures are needed for the catalyst to be effective.

"The new catalysts are also longer lasting too. And because of that, less of them are needed, reducing the cost of manufacturing drugs," added Vincent Lavallo, an undergraduate researcher in Bertrand's laboratory.

Bertrand's research group plans to continue to modify the new carbenes to develop more efficient catalysts. "We're looking also for new catalytic reactions facilitated by these new carbene metal complexes," Lavallo said. "The CAACs have made the field of carbene chemistry more exciting than ever."