The author of 《Atom Transfer Coupling Reactions Performed With Benign Reducing Agents and Radical Traps》 were Xia, Katherine; Rubaie, Alia J.; Johnson, Brendan P.; Parker, Samantha A.; Tillman, Eric S.. And the article was published in Journal of Polymer Science, Part A: Polymer Chemistry in 2019. Reference of Cupric bromide The author mentioned the following in the article:
Monobrominated polystyrene (PSBr) was prepared by ATRP, and the resulting chain ends were activated in the presence of radical traps to induce chain end-coupling. In atom transfer radical coupling (ATRC) with radical trap assistance, to achieve significant coupling requires excess metal catalyst, ligand, and a reducing agent that is often addnl. metal. In this work, activators generated by electron transfer (AGET) and radical trap assistance are used in the ATRC sequence to successfully lead to chain-end coupling without the need for the oxidatively unstable copper (I) and with environmentally friendlier agents in place of copper metal. High extents of coupling (Xc) were achieved using ascorbic acid (AA) as the reducing agent and copper(II) bromide as the oxidized version of the catalyst, and when combined with AGET ATRP to prepare the PSBr precursor, only a fraction of the total metal was required compared to traditional atom transfer reactions, while still retaining similar Xc values. In the experiment, the researchers used many compounds, for example, Cupric bromide(cas: 7789-45-9Reference of Cupric bromide)
Cupric bromide(cas: 7789-45-9) can be used as reducing agent, when complexed by three molecules of pyridine initiators for the controlled polymerization of styrene, methyl acrylate and methyl methacrylate.Reference of Cupric bromide
Referemce:
Copper catalysis in organic synthesis – NCBI,
Special Issue “Fundamentals and Applications of Copper-Based Catalysts”