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Activation–Deactivation Equilibrium Associated With Iron‐Mediated Atom‐Transfer Radical Polymerization up to High Pressure
Author(s) -
Schroeder Hendrik,
Yalalov Denis,
Buback Michael,
Matyjaszewski Krzysztof
Publication year - 2012
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201200244
Subject(s) - chemistry , atom transfer radical polymerization , solvent , monomer , polymerization , acetonitrile , equilibrium constant , catalysis , photochemistry , polymer chemistry , atom (system on chip) , polymer , organic chemistry , computer science , embedded system
Abstract The equilibrium constant, K model , of iron‐mediated atom‐transfer radical polymerization (ATRP) is investigated for FeBr 2 /α‐bromoester model systems in the absence of monomer. Quantitative analysis is carried out in solution of either N ‐methylpyrrolidin‐2‐one (NMP) or acetonitrile (MeCN) via high‐pressure online VIS/NIR spectroscopy monitoring the formation of the Fe III species. The reaction volume is determined to be Δ V R = 13 ± 3 cm 3 mol −1 , which indicates that K model decreases with pressure. This observation points to preferred formation of catalytically inactive or less active iron–solvent complexes toward higher pressure. Thus suitable solvent selection is important for the development of efficient iron‐based ATRP catalysts.