Most chemical research is based around making molecules that improve human health, or the environment, or energy and electronics – among other things.
But sometimes, chemists want to make molecules that are simply geometrically interesting. Creating these molecules is a technical challenge – but it can lead to breakthroughs in all the other fields. When soccerball-shaped “Buckyballs”, for instance, were turned into carbon nanotubes, the discovery sparked a revolution in materials science.
Now a team of Japanese chemists have made a molecule shaped like a Möbius strip. The molecule is a round belt of carbon atoms, linked to each other in hexagon shapes (like graphite) – and called a carbon nanobelt. The researchers have figured out how to make the belt with a twist, so that it only has one surface.
“The Möbius carbon nanobelt was a dream molecule in the scientific community after we reported the first chemical synthesis of a carbon nanobelt – an ultra-short carbon nanotube – in 2017,” says Kenichiro Itami, a professor at Nagoya University, Japan, and senior author on a paper describing the research, published in Nature Synthesis.
“Just like belts we use every day, we imagined what would happen to our ‘molecular belt’ when tightened with a twist. It’s another amazingly beautiful molecule.”
Unlike a paper Möbius strip, the molecule took more than some scissors and tape to create. In fact, because of its unusual shape, placing strain on the carbon atoms in its belt, making the molecule was deeply complicated.
“We knew from our previous synthesis of carbon nanobelts that the strain energy is the biggest hurdle in the synthesis,” says co-author Yasutomo Segawa. “Moreover, the additional twist within the belt structure makes the strain energy of the final target molecule even higher.”
The researchers had to run 14 chemical reactions, one after the other, to make the Mobius strip molecule.
But now it’s done, they’re hoping it will lead to more developments in nanocarbons and materials science.
“The key to the success in the actual synthesis was our molecular design and detailed examination of the reaction conditions,” adds Segawa.