Day three of the Belgian Organic Synthesis Symposium, and the heat wave continues. That means there have been plenty of excuses for conference attendees to drink Belgian beer, as the title of this blog implies. But we were also treated to a spectacular talk today by Kenichiro Itami, who presented (among other things) his latest research towards the bottom-up synthesis of carbon nanotubes.
Itami’s grand strategy is to prepare nanorings of benzenes, known as cycloparaphenylenes (CPPs), then to stack them up into cylinders and join them together in aromatization reactions – hey presto, you get a carbon nanotube. He’s not the only person pursuing this strategy, as both Carolyn Bertozzi and Shigeru Yamago seem to be trying the same thing.
The first problem to overcome in this approach was how to make the inherently ring-strained CPPs – Bertozzi published her solution in 2008 (you can see the abstract for the JACS paper here), closely followed by Itami in 2009 (in Angewandte, abstract here), then by Yamago this year (also in Angewandte, abstract here). Itami is now concentrating on finding a scaleable route for making CPPs, so that he has sufficient material to attempt the all-important aromatization reaction. He’s not quite there yet, but he has come up with an impressively concise synthesis of a CPP, and just needs to optimize the yields.
In the mean time, he’s also devised a general, modular synthesis that allows access to CPPs of different sizes, and he presented some rather beautiful crystal structures of a CPP – interestingly, the molecules stack up in much the way you would need them to if you wanted to fuse them together into a nanotube.
No doubt Bertozzi and Yamago are also making advances of their own, so I’ll certainly be following the progress in the race for a bottom-up synthesis of carbon nanotubes.
Andrew Mitchinson (Senior Editor, Nature)