In the formation of life on Earth and its subsequent evolution, carbon has played a central role. This is especially due to its unique bonding capabilities, allowing a wide variety of molecules to form. It is for this reason that the area of chemistry dealing with carbon molecules came to be called organic chemistry, as opposed to inorganic chemistry. This separation was also originally made based on the idea that organic molecules have a special “vital force”, and cannot be made from inorganic ones. This was eventually proved to be totally incorrect in 1828 when urea was synthesized from an inorganic substance.
Benzene, a six-carbon ring, is a key molecule in the science of life, discovered in 1825 by Michael Faraday, a physicist and chemist. Although in the 19th century people were very interested in benzene, by its end this enthusiasm had vanished, along with a general feeling that there was nothing further to be learned from organic chemistry. Interest was later regained because of the resonance theory of quantum mechanics. Whereas before benzene was thought to involve a quickly equilibrating double bond, it was now understood to be a conjugated structure. Synthetic chemists subsequently found many interesting ways to add functionality to organic molecules, especially those involving benzene: catalysts, anti-inflationary materials, cancer fighting drugs, and a conducting polymer are examples. In the 20th century, benzene thus recovered its prime status in chemistry.
The Buckyball was discovered in 1985 (also called C60, C70 or fullerene, after Buckminister Fuller, an architect of geodesic domes). Whereas inorganic chemists see these fullerenes and later discovered nanotubes as interesting structures unrelated to life, organic chemists see huge clusters of benzene rings. These clusters can also be considered as polymers of benzene. Though a majority of people thought that fullerenes and nanotubes are interesting, Eiichi Nakamura thought that their organic derivatives would be much more interesting, since this was the case in the history of benzene. Nakamura started working on buckyballs in 1992, when they first became available in sufficient quantity. His group was among the first to use this new structure in synthetic chemistry. Nakamura immediately thought that if side-chain structures could be assembled to these clusters they might exhibit interesting functionality, such as drugs. One of the first functional molecules produced was an enzyme-like molecule in 1993 that had the ability to cut DNA.
In 1996 Nakamura succeeded to convert isotropic C60 into anisotropic C60. Using magnesium with a copper catalyst, it was possible to put 5 phenyl groups or 5 methyl groups at very specific regions of C60. Most importantly, the product was 100% pure and in 100% yield. This was the first and essentially the only reaction that converts C60 into organic C60. Using these handles, it was possible to attach the long side chains to methyl groups. Because C60 is essentially a round ball it is difficult to align for materials and functions. However, by considering a badminton shuttlecock, a molecular recognition was conceived where the ball part recognizes the feather part and aligns. These molecules were put together in one dimension in a crystalline material. This very unique structure shows possible use as a liquid-crystal material, which is being pursued.
In addition, Nakamura is also investigating a number of interesting and potentially functional materials. From a technological point of view, Nishi of Sony Corporation has been quoted as saying that in the past there were the ages of stone, bronze, iron and silicon; and that we are now entering the carbon age. Although carbon can never replace silicon, they are certainly complementary.