Templated Synthesis of End-Functionalized Graphene Nanoribbons through Living Ring-Opening Alkyne Metathesis Polymerization

Atomically precise bottom-up synthesized
graphene nanoribbons (GNRs)
are promising candidates for next-generation electronic materials.
The incorporation of these highly tunable semiconductors into complex
device architectures requires the development of synthetic tools that
provide control over the absolute length, the sequence, and the end
groups of GNRs. Here, we report the living chain-growth synthesis
of chevron-type GNRs (cGNRs) templated by a poly-(arylene ethynylene)
precursor prepared through ring-opening alkyne metathesis polymerization
(ROAMP). The strained triple bonds of a macrocyclic monomer serve
both as the site of polymerization and the reaction center for an
annulation reaction that laterally extends the conjugated backbone
to give cGNRs with predetermined lengths and end groups. The structural
control provided by a living polymer-templated synthesis of GNRs paves
the way for their future integration into hierarchical assemblies,
sequence-defined heterojunctions, and well-defined single-GNR transistors
via block copolymer templates.