Reactivity of methacrylates in insertion polymerization

Thomas Rünzi, Damien Guironnet, Inigo Göttker-Schnetmann, Stefan Mecking

Research output: Contribution to journalArticlepeer-review

Abstract

Polymerization of ethylene by complexes [{(P∧O)PdMe(L)}] (P∧O = κ2-(P,O)-2-(2-MeOC6H4)2PC 6H4SO3)) affords homopolyethylene free of any methyl methacrylate (MMA)-derived units, even in the presence of substantial concentrations of MMA. In stoichiometric studies, reactive {(P∧O)Pd(Me)L} fragments generated by halide abstraction from [({(P∧O)Pd(Me)Cl}μ-Na) 2] insert MMA in a 1,2- as well as 2,1-mode. The 1,2-insertion product forms a stable five-membered chelate by coordination of the carbonyl group. Thermodynamic parameters for MMA insertion are ΔH = 69.0(3.1) kJ mol-1 and ΔS = -103(10) J mol-1 K-1 (total average for 1,2- and 2,1-insertion), in comparison to ΔH = 48.5(3.0) kJ mol-1 and ΔS = -138(7) J mol-1 K-1 for methyl acrylate (MA) insertion. These data agree with an observed at least 102-fold preference for MA incorporation vs MMA incorporation (not detected) under polymerization conditions. Copolymerization of ethylene with a bifunctional acrylate-methacrylate monomer yields linear polyethylenes with intact methacrylate substituents. Post-polymerization modification of the latter was exemplified by free-radical thiol addition and by cross-metathesis.

Original languageEnglish (US)
Pages (from-to)16623-16630
Number of pages8
JournalJournal of the American Chemical Society
Volume132
Issue number46
DOIs
StatePublished - Nov 24 2010
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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