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Updated: Mar 21, 2026

A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes
Published on: February 27, 2017
Introducing "Ynene" Metathesis: Ring-Expansion Metathesis Polymerization Leads to Highly Cis and Syndiotactic Cyclic
Soufiane S Nadif1, Tomohiro Kubo2, Stella A Gonsales1
1Center for Catalysis, Department of Chemistry, University of Florida , P.O. Box 117200, Gainesville, Florida 32611, United States.
Abstract:
Tungsten alkylidynes [CF3-ONO]W≡CC(CH3)3(THF)2 (1) and [(t)BuOCO]W≡CC(CH3)3(THF)2 (3) react with ethylene. Complex 1 reacts reversibly with ethylene to give the metallacyclobutene (2). Complex 3 reacts with ethylene to form the tethered alkylidene (4) featuring a tetraanionic pincer ligand. Complexes 1 and 3 initiate the polymerization of norbornene at room temperature. The polymerization of norbornene by 1 is not stereoselective, whereas 3 generates a highly cis and syndiotactic cyclic polynorbornene. Comparison of the intrinsic viscosity, radius of gyration, and elution time of the synthesized cyclic polynorbornene with those of linear analogues provides conclusive evidence for a cyclic topology.
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