Embedding diazirine-based carbene precursors into polyolefins via catalyst-tuned olefin metathesis
Hong-Gyu Seong, Mizhi Xu, Haley K. Beech, Youngbum Lee, Kazuhisa Iwaso, Craig J. Hawker
Polym. Chem. August 2026
Abstract: Polyolefins are among the most widely produced polymeric materials, yet their chemically inert hydrocarbon backbones limit opportunities for direct functionalization and crosslinking. Diazirines are powerful carbene precursors for C–H insertion, but their compatibility with olefin metathesis catalysts remains unclear due to potential interactions with reactive metal–carbene intermediates. Here, we demonstrate that diazirine compatibility in the metathesis polymerization of cis-cyclooctene derivatives can be controlled through catalyst selection. Using this approach, a diazirine-functionalized cis-cyclooctene monomer (COE-Dz) was synthesized and incorporated into polyolefin backbones via ring-opening metathesis copolymerization. Screening of ruthenium benzylidene catalysts reveals pronounced differences in diazirine stability, identifying conditions under which the reactive diazirine unit is preserved with minimal detectable loss during polymerization. Under these conditions, copolymerization with cis-cyclooctene affords polyolefins with tunable molecular weights and diazirine content. These linear polyolefin-based materials act as macromolecular carbene precursors, enabling efficient thermal C–H insertion and crosslinking of polybutadiene to form elastomeric networks at low diazirine loadings. A key consequence of this work is the establishment of a general strategy for integrating latent carbene functionality into metathesis-derived polyolefins, expanding the scope of functional materials accessible through olefin metathesis.
