Temporal control in atom transfer radical polymerization (ATRP) relies on modulating the oxidation state of a copper catalyst, as polymer chains are activated by L/Cu I and deactivated by L/Cu II . (Re)generation of L/Cu I activator has been achieved by applying a multitude of external stimuli. However, switching the Cu catalyst off by oxidizing to L/Cu II through external chemical stimuli has not yet been investigated. A redox switchable ATRP was developed in which an oxidizing agent was used to oxidize L/Cu I activator to L/Cu II , thus halting the polymerization. A ferrocenium salt or oxygen were used to switch off the Cu catalyst, whereas ascorbic acid was used to switch the catalyst on by (re)generating L/Cu I . The redox switches efficiently modulated the oxidation state of the catalyst without sacrificing control over polymerization.
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Investigation of a zirconium compound for redox switchable ring opening polymerization
A zirconium compound, (salfen)Zr(O i Pr) 2 (salfen = N , N ′-bis(2,4-di- tert -butylphenoxy)-1,1′-ferrocenediimine), was tested as a redox switchable catalyst for the ring opening polymerization of cyclic esters and epoxides. Different activities were observed in the reduced and oxidized state, and an orthogonal switch on monomer activities could be achieved. Diblock and triblock copolymers were synthesized using an in situ redox switch of the catalyst oxidation state.
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- Award ID(s):
- 1809116
- NSF-PAR ID:
- 10101110
- Date Published:
- Journal Name:
- Dalton Transactions
- Volume:
- 48
- Issue:
- 9
- ISSN:
- 1477-9226
- Page Range / eLocation ID:
- 2996 to 3002
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C9DT00212J
