Nickel‐Catalyzed Reductive Homodimerization of Brominated Polystyrene Chains. Issue 24 (11th October 2022)

• Record Type: Journal Article
• Authors: Basler, Eleanor D.; Chong, Jaden L.; Heath, Chloe M.; Ching, Katie S.; Jennett, Shelby T.; Tillman, Eric S.
• Is Part Of: Macromolecular chemistry and physics. Volume 223:Issue 24(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-11
• Subjects: ATRP -- catalysis -- mechanisms -- polystyrene -- reductive coupling; Polymers -- Periodicals; Polymerization -- Periodicals; Synthetic products -- Periodicals; Macromolecules -- Periodicals; 547.7
• DOI: 10.1002/macp.202200320
• Languages: English
• ISSNs: 1022-1352

Abstract

Abstract: A nickel‐based catalytic system leading to high yields (≈80%) of polymer chain coupling has been developed. The extent of coupling ( X c ) is found to be relatively high (>75%) and consistent across a wide range of catalyst loadings (0.1 – 1.0 equivalent with respect to the chain end), comparing favorably with other chain‐end joining methods. A mechanistic cycle is proposed to occur with benzylic chain‐end radical intermediates, consistent with the addition of a nitroso radical trap substantially lowering coupling yields. The effect of the polymer chain end (Cl vs Br) and the halide associated with the nickel catalyst is also probed. Abstract : Brominated polystyrene chains are effectively dimerized by a nickel‐catalyzed reductive coupling cycle, with high yields (80%) of chain‐end coupling observed across a wide range of conditions. The mechanism appears to involve the generation of polystyrene radicals which are captured by the nickel catalyst as part of catalytic cycle.