Fjord-Edge Graphene Nanoribbons with Site-Specific Nitrogen Substitution

Abstract

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 <b>3a,b</b> into the fjord-edge nitrogen-doped graphene nanoribbon structures <b>1a,b</b> (fjord-edge N₂[8]GNRs). Structural assignments are confirmed by CP/MAS ¹³C NMR, Raman, and XPS spectroscopy. The fjord-edge N₂[8]GNRs <b>1a,b</b> are promising precursors for the novel backbone nitrogen-substituted N₂[8]_AGNRs <b>2a,b</b>. Geometry and band calculations on N₂[8]_AGNR <b>2c</b> indicate that this class of nanoribbons should have unusual bonding topology and metallicity.