Carbon-60 fullerenes–cagelike molecules of 60 carbon atoms (C60)–are easily coaxed
into polymer chains. Trying to do the same for less-symmetrical C70 fullerenes has
proven so frustrating, however, that some scientists have speculated that it can’t
Never say never. In the July 27 Science, Alexander V. Soldatov, now of Harvard
University, and researchers in Germany, Russia, Austria, and Sweden describe how
they managed the feat.
Computer modeling enabled the researchers to identify a crystal form of C70 in
which the molecules align in an orientation that could lead to polymerization.
After exposing a single crystal to high pressures and temperatures to trigger such
a reaction, the researchers used spectroscopy, X-ray diffraction, and nuclear
magnetic resonance imaging to examine the result. Their data showed that they
indeed had created zigzagging polymeric chains of C70.
This is the first time that researchers have determined the atomic positions in a
fullerene polymer, claims Soldatov. Such molecular-scale detail might help
researchers find ways to use high pressure to convert fullerenes into superhard
materials, he says.