Ring-Opening Metathesis Polymerization of Nitrile Substituted cis-Cyclooctenes

New nitrile‐containing polymers have been synthesized by ring‐opening metathesis polymerization of cis‐cyanocyclooct‐4‐ene and cis‐1,2‐dicyanocyclooct‐5‐ene with a 2nd generation Grubbs catalyst [(H2IMes)(PCy3)Cl2Ru = CHPh] (H2IMes = N,N′‐bis(mesityl)‐4,5‐dihydroimidazol‐2‐ylidene). With increasing content of nitrile moieties on the cyclooctene ring the reaction rates decrease from cis‐cyclooctene to cis‐cyanocyclooct‐4‐ene and cis‐1,2‐dicyanocyclooct‐5‐ene. Contrary to commercially available nitrile rubbers (unhydrogenated and hydrogenated butadiene/acrylonitrile copolymers) in which double bonds, nitrile moieties, and methylene bridges are randomly distributed along the main chain, the new polymers show a regular distribution of structural entities. The synthesis of new nitrile‐containing polymers by ring‐opening metathesis polymerization (ROMP) of cis‐cyanocyclooct‐4‐ene and cis‐1,2‐dicyanocyclooct‐5‐ene is reported. Polymerization rates and molar masses decrease with the number of nitrile groups attached to the cyclooctene ring.