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Selective and Rapid Light‐Induced RAFT Single Unit Monomer Insertion in Aqueous Solution
Author(s) -
Zhou Yanyan,
Zhang Zhengbiao,
Reese Cassandra M.,
Patton Derek L.,
Xu Jiangtao,
Boyer Cyrille,
Postma Almar,
Moad Graeme
Publication year - 2020
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201900478
Subject(s) - raft , monomer , chain transfer , photochemistry , aqueous solution , chemistry , porphyrin , polymer chemistry , catalysis , materials science , copolymer , radical polymerization , polymer , organic chemistry
The photocatalyst Zn(II) meso ‐tetra(4‐sulfonatophenyl)porphyrin (ZnTPPS) is found to substantially accelerate visible‐light‐initiated (red, yellow, green light) single unit monomer insertion (SUMI) of N , N ‐dimethylacrylamide into the reversible addition–fragmentation chain transfer (RAFT) agent, 4‐((((2‐carboxyethyl)thio)carbonothioyl)thio)‐4‐cyanopentanoic acid (RAFT 1 ), in aqueous solution. Thus, under irradiation with red (633 nm) or yellow (593 nm) light with 50 mpm (moles per million mole of monomer) ZnTPPS at 30 °C, the rate enhancement provided by photoinduced energy or electron transfer (PET) is ≈sevenfold over the rate of direct photoRAFT‐SUMI (without catalyst), which corresponds to achieving full and selective reaction in hours versus days. Importantly, the selectivity, as judged by the absence of oligomers, is retained. Under green light at similar power, higher rates of SUMI are also observed. However, the degree of enhancement provided by PET‐RAFT‐SUMI over direct photoRAFT‐SUMI as a function of catalyst concentration is less and some oligomers are formed.