Introducing "Ynene" Metathesis: Ring-Expansion Metathesis Polymerization Leads to Highly Cis and Syndiotactic Cyclic Polymers of Norbornene

Soufiane S Nadif; Tomohiro Kubo; Stella A Gonsales; Sudarsan VenkatRamani; Ion Ghiviriga; Brent S Sumerlin; Adam S Veige

doi:10.1021/jacs.6b03247

Introducing "Ynene" Metathesis: Ring-Expansion Metathesis Polymerization Leads to Highly Cis and Syndiotactic Cyclic Polymers of Norbornene

J Am Chem Soc. 2016 May 25;138(20):6408-11. doi: 10.1021/jacs.6b03247. Epub 2016 May 17.

Authors

Soufiane S Nadif¹, Tomohiro Kubo², Stella A Gonsales¹, Sudarsan VenkatRamani¹, Ion Ghiviriga^{1

2}, Brent S Sumerlin², Adam S Veige^{1

2}

Affiliations

¹ Center for Catalysis, Department of Chemistry, University of Florida , P.O. Box 117200, Gainesville, Florida 32611, United States.
² Center for Macromolecular Science & Engineering and George & Josephine Butler Polymer Research Laboratory, Department of Chemistry, University of Florida , P.O. Box 117200, Gainesville, Florida 32611, United States.

PMID: 27172120
DOI: 10.1021/jacs.6b03247

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.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.