Turning Jumbo Molecules Into Chemical Factories

For materials science, March rolled in with a surprise and went out with an even bigger one. First, a team headed by Yale University chemist Martin Saunders made an intriguing discovery about buckyballs. When the soccer-ball-shaped molecules are heated to more than 1,112F, a door opens. Through it, a few atoms can be stuffed inside the carbon spheres, making it possible to combine elements that cannot be joined by chemical bonding.

Then, at the end of March, University of Michigan scientists unveiled the world's biggest hydrocarbon molecule at a meeting of the American Chemical Society (ACS). Also spherical in shape, its diameter is five times that of a buckyball, giving it 100 times more internal capacity. This jumbo molecule can gobble up 1,000 or more atoms--enough to make it useful for delivering drugs to target organs within the body, says chemist Jeffrey S. Moore, who led the Michigan research.

More important, it should be possible to tailor the stuffing so that the molecules would act as microchemistry factories. One of Moore's goals is to develop a system that would mimic plants and turn sunlight into chemical energy.

Other researchers are also trying to build jumbo molecules for microchemistry. At the ACS meeting, Cornell University chemists reported on a technique for growing so-called dendritic polymers that repeatedly branch until they form a sphere. In one potential application, such a ball has an exterior that attracts water and an interior that repels water. This may be a different way to combine two ingredients that normally won't mix, such as oil and water.