The nature of Cu(II) species in ATRP: New insights via EPR |
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| Authors: | Ignacio Caretti Bart Dervaux Filip E. Du Prez Sabine Van Doorslaer |
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| Affiliation: | 1. Department of Physics, University of Antwerp, Universiteitsplein 1 (Building N), 2610 Wilrijk, Belgium;2. Department of Organic Chemistry, Polymer Chemistry Research Group, Ghent University, Krijgslaan 281 (S4‐bis), 9000 Ghent, Belgium |
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| Abstract: | Identification of the paramagnetic species present in the Cu(I)Br‐catalyzed atom transfer radical polymerization (ATRP) of a model monomer (isobornyl acrylate) has been carried out by electron paramagnetic resonance (EPR) in the continuous wave mode at 90 K. Up to five different species—four copper‐based species and one organic radical—were detected with this technique. The EPR parameters of the copper‐based species are found to differ strongly, and originate from diverse isolated Cu(II) complexes, as well as dipolarly interacting and even exchange‐coupled Cu(II) species. The work highlights the complexity of the copper‐based EPR signal observed in copper‐mediated ATRP reactions. Analysis of the time evolution of the individual EPR contributions reveals the disadvantages of quantitative kinetics studies based on the summed EPR intensity of all copper‐based species, as is commonly used in literature for this type of reactions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1493–1501, 2010 |
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| Keywords: | acrylate atom transfer radical polymerization (ATRP) ESR/EPR continuous wave Cu(II) species kinetics (polym.) |
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