The Cover Feature shows a mechanical grinding process with the help of metal balls that enable transformation of a planar polyarene into a curved aromatic structure. The illustration was made by Cheryn Liaw Yu Ting. More information can be found in the Research Article by G. Báti, S. Laxmi et al.
Mechanochemical synthesis of corannulene by ball milling technique is shown to be a highly efficient and scalable process. Through this method, 15 g of corannulene could be obtained in a single milling cycle in 90 % isolated yield.
Corannulene, a curved polycyclic aromatic hydrocarbon, is prepared in a multigram scale through mechanochemical synthesis. Initially, a mixer mill approach is examined and found to be suitable for a gram scale synthesis. For larger scales, planetary mills are used. For instance, 15 g of corannulene could be obtained in a single milling cycle with an isolated yield of 90 %. The yields are lower when the jar rotation rate is lower or higher than 400 revolutions per minute (rpm). Cumulatively, 98 g of corannulene is produced through the ball milling-based grinding techniques. These results indicate the future potential of mechanochemistry in the rational chemical synthesis of highly curved nanocarbons such as fullerenes and carbon nanotubes.