Synthesis of Polybenzoquinolines as Graphene Nanoribbon Precursors

Abstract

The bottom-up synthesis of graphene nanoribbons (narrow strips of sp2 hybridized carbon) has attracted much attention in recent years, with a number of contemporary demonstrations of the preparation of allcarbon systems. However, a limited number of studies have addressed the solution-phase synthesis of heteroatom-doped graphene nanoribbons; the design and preparation of such constructs is a significant challenge. We have recently developed new synthetic methodologies for the synthesis of oligobenzoquinolines via the aza-Diels–Alder (Povarov) reaction, producing oligobenzoquinoline precursors whose length and sequence are precisely controlled. Our straightforward approach also provides access to crowded macromolecular polybenzoquinoline scaffolds, which are key intermediates for the preparation of nitrogen-doped nanoribbons. Altogether, these findings hold implications for the bottom-up synthesis of graphene nanoribbons whose edge character, terminal functionalities, doping, and length are precisely defined.