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Kinetics of Fe–Mesohemin–(MPEG500)2‑Mediated RDRP in Aqueous Solution
journal contribution
posted on 2016-10-21, 14:51 authored by Sebastian Smolne, Michael Buback, Serhiy Demeshko, Krzysztof Matyjaszewski, Franc Meyer, Hendrik Schroeder, Antonina SimakovaA speciation
analysis for Fe–mesohemin–(MPEG500)2-mediated reversible-deactivation radical polymerization
(RDRP) in aqueous solution was carried out by a combination of visible
(vis) and 57Fe Mössbauer spectroscopy. The results
were used within kinetic studies of ATRP and OMRP reactions via highly
time-resolved EPR spectroscopy. ATRP control was effective with the
rate coefficient for deactivation clearly exceeding the one for formation
of organometallic species. Deactivation rate coefficients increase
by more than 1 order of magnitude in passing from polymerization in
30 to 90 wt % H2O. Media with water contents of and above
70 wt % are well suited for controlled ATRP. The Fe–mesohemin
catalyst provides an exceptionally high ATRP equilibrium constant
even at ambient temperature, which approaches the one of highly active
Cu catalysts.