The Rolling-Up of Oligophenylenes to Nanographenes by a HF-Zipping Approach
The fascinating properties of graphene have resulted in exploding interest in the synthesis of large polycyclic aromatic hydrocarbons or nanographenes, which represent fragments of the graphene surface. Dr. Konstantin Amsharov and PhD student Anni-Kristin Steiner (Institute of Organic Chemistry, FAU) have discovered an alternative method for the synthesis of such carbon-based nanostructures. Authors have found that alumina mediated activation of carbon-fluorine bond (the strongest bonds to carbon), leads to effective carbon-carbon bond formation.
Following this strategy, it is possible to construct various nanostructures in near-quantitative yields, including highly strained bowl-shaped systems which are not accessible via other synthetic routes. Authors show that this unprecedentedly challenging transformation is possible even in a domino mode (zipping): Each individual step can be unambiguously programmed by a proper design of the precursor molecule. Despite the flexible nature of the fluorine-containing precursors, a very efficient regioselective zipping to the target nanostructures was achieved. The alumina-mediated HF-zipping process is characterized by exceptionally smooth conversion into the desired nanographenes.
Remarkably, all synthesized molecules were obtained in highly pure form without additional purification procedures. As a result, the concept is superior to existing methods and this approach could possibly provide access to highly interesting carbon nanostructures which are difficult to access by existing alternative methods.
Steiner, A.-K. and Amsharov, K. Y. (2017), The Rolling-Up of Oligophenylenes to Nanographenes by a HF-Zipping Approach. Angew. Chem. Int. Ed.. doi:10.1002/anie.201710002