Kinetic study of living ring-opening metathesis polymerization with third-generation grubbs catalysts

Dylan J. Walsh, Sii Hong Lau, Michael G. Hyatt, Damien Guironnet

Research output: Contribution to journalArticlepeer-review

Abstract

The rate of living ring-opening metathesis polymerization (ROMP) of N-hexyl-exo-norbornene-5,6- dicarboximide initiated by Grubbs third-generation catalyst precursors [(H2IMes)(py)2(Cl)2Ru=CHPh] and [(H2IMes)(3-Br-py)2(Cl)2Ru=CHPh] is measured to be independent of catalyst concentration. This result led to the development of a rate law describing living ROMP initiated by a Grubbs third-generation catalyst that includes an inverse first-order dependency in pyridine. Additionally, it is demonstrated that one of the two pyridines coordinated to the solid catalyst is fully dissociated in solution. The monopyridine adduct formation is confirmed in solution by 1H DOSY (diffusion-ordered NMR spectroscopy), and a Van't Hoff analysis of the equilibrium between mono- and dipyridine adducts (extrapolated Keq,0 ~ 0.5 at 25 °C). Finally, the difference in polymerization rates between two catalyst precursors is demonstrated to correspond to the difference in coordination strength between the two pyridines, suggesting that the catalytic species involved in the polymerization's rate-determining step is not coordinated to pyridine.

Original languageEnglish (US)
Pages (from-to)13644-13647
Number of pages4
JournalJournal of the American Chemical Society
Volume139
Issue number39
DOIs
StatePublished - Oct 4 2017

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry

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