Open AccessExperimental and Theoretical Comparison of Addition–Fragmentation Pathways of Diseleno- and Dithiocarbamate RAFT Agents
Author(s) -
D. Matioszek,
Stéphane Mazières,
Oleksii Brusylovets,
Ching Yeh Lin,
Michelle L. Coote,
Mathias Destarac,
Simon Harrisson
Publication year - 2019
Publication title -
macromolecules
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.994
H-Index - 313
eISSN - 1520-5835
pISSN - 0024-9297
DOI - 10.1021/acs.macromol.9b00214
Subject(s) - raft , chain transfer , chemistry , dithiocarbamate , adduct , reactivity (psychology) , monomer , transfer agent , fragmentation (computing) , polymer chemistry , reaction rate constant , polymerization , organic chemistry , radical polymerization , kinetics , polymer , medicine , physics , alternative medicine , pathology , quantum mechanics , computer science , operating system
Theoretical studies suggest that identically substituted dithio- and diselenocarbamate reversible addition–fragmentation chain transfer (RAFT) agents will have similar reactivity but that diselenocarbamate RAFT agents are more likely to undergo intermediate radical termination. These results are supported by an experimental study of polymerizations of vinyl acetate mediated by Se-cyanomethyl N,N-dimethyldiselenocarbamate (1Se) and its sulfur analog, S-cyanomethyl N,N-dimethyldithiocarbamate (1S). While the two polymerizations had similar interchain transfer constants (3.2 for 1S and 3.9 for 1Se), significant retardation was observed for 1Se-mediated polymerizations. External chain transfer constants were also measured for 1S (5.4) and 1Se (45). The low apparent value of the chain transfer constant of 1S is attributed to the selective formation of a single monomer adduct in the early stages of the reaction.
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