Nobel winners made carbon dance
The fathers of a powerful catalytic tool nab this year's chemistry award.
This year's Nobel Prize in Chemistry goes to three researchers who made the everyday task of making molecules infinitely easier for working chemists.
Yves Chauvin of the French Oil Institute in Rueil-Malmaison near Paris showed how a type of reaction known as metathesis actually works. The process transforms a certain class of carbon compounds and has been known to the petrochemicals industry since the 1950s.
Chauvin's explanations in the early 1970s helped Richard Schrock at the Massachusetts Institute of Technology (MIT) in Cambridge and Robert Grubbs of the California Institute of Technology, Pasadena, to develop catalysts that make metathesis more controllable and reliable.
"It has fundamentally transformed the way chemists think about building molecules," says Gregory Fu at MIT, who was a postdoc with Grubbs when he devised his catalyst in the early 1990s.
The award "is what we've all been waiting for", says Steven Ley, an organic chemist at the University of Cambridge, UK. "The work is spectacularly useful and important; it is the discovery in chemistry of the past 30 years."
All change, please
Metathesis has taken a route, not unusual in chemistry, from industry to the academic laboratory and then back out to industry. Along the way, it was transformed from a curious observation to a systematic and useful piece of science.
"People knew there was this funny reaction in petroleum refining," says John Brown, an organic chemist at the University of Oxford, UK. "Chauvin gave the first serious mechanism that turned it into rational science. But it was still just a party piece until Schrock came along."
The process involves two molecules that each contain a double bond between carbon atoms. The bond acts rather like a double handclasp between a pair of dancers, and during the reaction, which requires a catalyst containing metal atoms, the molecules effectively exchange partners (metathesis simply means 'changing places'). "The molecules are cut in half and put back together again," explains Brown.
In 1971 Chauvin and his student Jean-Louis Hérisson showed how the metal-atom catalyst coordinates the rearrangement of carbon bonds.
Soon after, Schrock began to look for more effective catalysts than those found by trial-and-error in industry. Between 1980 and 1990 he found that compounds containing molybdenum and tungsten were particularly efficient.
But Schrock's catalysts still had a drawback: they tended to react with other molecular groups attached to the double bonds, which chemists often needed to put there to create their target molecule. In 1992, Grubbs discovered that ruthenium compounds interfered less, and were more stable in air.
"That is really what rocketed the reaction into common use," says Ley.
The chemists' prize
"It has revolutionized organic synthesis," he adds. "I don't think there is a single organic chemist who hasn't used metathesis... and if they haven't, they should have."
The award is a reminder that in chemistry the most valued contributions to the field are often not discoveries, but tools.
A general way to make molecules, such as that which the metathesis catalysts provide, can find many different applications. "Most people have these catalysts on their shelves," says Fu.
"It's a real chemists' award," adds Ley, "and these are absolutely the obvious people to give it to."