13C kinetic isotope effects in the copper(I)-mediated living radical polymerization of methyl methacrylate.
Carbon-13 kinetic isotope effects (KIEs) have been determined for free-radical and copper-mediated living radical polymerizations of methyl methacrylate at 60 degrees C. While free-radical polymerization shows only one primary 13C KIE, on the least-substituted double bond carbon (k12/k13 = 1.045), two significant KIEs are observed, one on each double bond carbon, for copper-mediated polymerization (k12/k13(H2C=) = 1.050, k12/k13(=C <) = 1.010), showing that copper-mediated living radical polymerization does not propagate via a simple free radical process.
Department of Chemistry, University of Warwick, Coventry, UK CV4 7AL.
Simon
S
Harrisson
Jonathan P
JP
Rourke
David M
DM
Haddleton