Fjord-Edge Graphene Nanoribbons with Site-Specific Nitrogen Substitution

The synthesis of graphene nanoribbons (GNRs) that contain site-specifically substituted backbone heteroatoms is one of the essential goals that must be achieved in order to control the electronic properties of these next generation organic materials. We have exploited our recently reported solid-state topochemical polymerization/cyclization-aromatization strategy to convert the simple 1,4-bis(3-pyridyl)butadiynes 3a,b into the fjord-edge nitrogen-doped graphene nanoribbon structures 1a,b (fjord-edge N-2[8]GNRs). Structural assignments are confirmed by CP/MAS C-13 NMR, Raman, and XPS spectroscopy. The fjord-edge N2[8]GNRs 1a,b are promising precursors for the novel backbone nitrogen-substituted N-2[8](A)GNRs 2a,b. Geometry and band calculations on N-2[8](A)GNR 2c indicate that this class of nanoribbons should have unusual bonding topology and metallicity.