Mechanistic Insight into the Photocontrolled Cationic Polymerization of Vinyl Ethers

• DOI: 10.1021/jacs.7b09539
• Publication Date: 2017-10-06T17:00:46Z
• Authors: Quentin Michaudel; Timothée Chauviré; Veronika Kottisch; Michael J. Supej; Katherine J. Staw...; Luxi Shen; Warren R. Zipfel; Héctor D. Abruña; Jack H. Freed; Brett P. Fors
• Keywords: Cationic polymerization; Living cationic polymerization

The mechanism of the recently reported photocontrolled cationic polymerization vinyl ethers was investigated using a variety catalysts and chain-transfer agents (CTAs) as well diverse spectroscopic electrochemical analytical techniques. Our study revealed complex activation step characterized by one-electron oxidation CTA. This is followed mesolytic cleavage resulting radical cation species, which leads to generation reactive cation-this species initiates ether monomer-and dithiocarbamate that likely in equilibrium with corresponding thiuram disulfide dimer. Reversible addition-fragmentation type degenerative chain transfer contributes narrow dispersities control over growth observed under these conditions. Finally, deactivation contingent upon reduced photocatalyst concomitant production anion caps polymer end. fine-tuning electronic properties redox potentials both excited ground states necessary obtain system rather than simply photoinitiated system. elucidation elementary steps this process will aid design new catalytic systems their real-world applications.