Scope and Limitations of the Dehydrogenative Generation of Graphenic Nanoribbons from Methylene-Bridged, Aromatic Ladder Polymers

A synthetic route to solubilized graphenic nanoribbons (GNRs) by oxidation of methylene-bridged, aromatic ladder polymers is presented. Hereby, the ladder polymer precursors are finally 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (or DDQ) oxidized into the desired GNRs. However, a detailed UV-vis analysis shows already partial oxidation/dehydrogenation during aqueous work-up under loss of ≈50% of the bridgehead hydrogens as well as some indications for overoxidation with DDQ under formation of quinoid carbonyl defects, additionally driven by a reduction of the number of quinoid (quinodimethane) structural units.