Graphene was reportedly first produced in 2004, and from then, scientists have been striving hard to use graphene and similar carbon-based materials to completely transform sports, electronics and several other fields.
Recently, scientists from Japan have made a breakthrough that will progress the long-elusive field of nanographene magnets.
In a study that was recently reported in the Journal of the American Chemical Society, scientists from Osaka University and collaborating partners have produced a crystalline nanographene that exhibits magnetic properties hypothesized since the 1950s. However, so far, these properties have not been proven experimentally besides at extremely low temperatures.
Graphene is a single layer, two-dimensional sheet of carbon rings aligned in a honeycomb lattice. The study analyzes the reason behind researchers getting excited about graphene. It has splendid properties — it displays effective, long-distance charge transport and exhibits a much higher strength compared to similarly thick steel.
Nanostructures of graphene contain edges that show electronic and magnetic properties that scientists would like to use. But graphene nanosheets are hard to make and it is difficult to analyze their zigzag edge properties. Overcoming such difficulties through an easy, yet latest, model system called triangulene is something the scientists at Osaka University aimed to achieve.
“Triangulene has long eluded synthesis in a crystalline form because of its uncontrolled polymerization. We prevented this polymerization by steric protection — bulking up the molecule — and did so in a way that didn’t affect its underlying properties,” state both Shinobu Arikawa and Akihiro Shimizu, the two main authors of the study.
The triangulene derivative achieved by the scientists seems to be stable at room temperature but should be kept in an inert atmosphere since it slowly degrades upon exposure to oxygen. However, crystallization was possible — which allowed verification of its theoretically anticipated properties, like localization of unpaired electrons on the molecules’ zigzag edges.
By measuring its optical and magnetic properties, we confirmed that our molecule is in the triplet ground state. This is an electronic state that can serve as an experimentally tractable model for zigzag-edged nanographene.
Ryo Shintani, Study Senior Author, Osaka University
Such outcomes have significant applications. Scientists can expand the long-sought synthetic procedure discussed here to raise the number of carbon rings present in the molecule and execute chemical syntheses of the latest forms of nanographene.
Through this, Osaka University and Osaka City University scientists might be able to synthesize materials that are foundational for advanced magnets and electronics of the future and supplement the silicon that is omnipresent in modern electronics.
Arikawa, S., et al. (2021) Synthesis and Isolation of a Kinetically Stabilized Crystalline Triangulene. Journal of Chemical Society. doi.org/10.1021/jacs.1c10151.