Effect of Trapping Agent and Polystyrene Chain End Functionality on Radical Trap-Assisted Atom Transfer Radical Coupling
Publication Date
2014
Description
Coupling reactions were performed to gauge the effect of the inclusion of a radical trap on the success of coupling reactions of monohalogenated polystyrene (PSX) chains in atom transfer radical coupling (ATRC) type reactions. The effect of both the specific radical trap chosen and the structure of the polymer chain end were evaluated by the extent of dimerization observed in a series of analogous coupling reactions. The commonly used radical trap 2-methyl-2-nitrosopropane (MNP) showed the highest amounts of dimerization for PSX (X = Br, Cl) compared to coupling reactions performed in its absence or with a different radical trap. A dinitroxide coupling agent was also studied with the extent of coupling nearly matching the effectiveness of MNP in RTA (Radical trap-assisted)-ATRC reactions, while N-nitroso and electron rich nitroso coupling agents were the least effective. (2,2,6,6-Tetramethyl-piperin-L-yl)oxyl-capped PS (PS-TEMPO), prepared by NMP, was subjected to a coupling sequence conceptually similar to RTA-ATRC, but dimerization was not observed regardless of the choice of radical trap. Kinetic experiments were performed to observe rate changes on the coupling reaction of PSBr as a result of the inclusion of MNP, with substantial rate enhancements found in the RTA-ATRC coupling sequence compared to traditional ATRC.
Journal
Polymers
Volume
6
Issue
11
First Page
2737
Last Page
2751
Department
Chemistry
Link to Published Version
DOI
10.3390/polym6112737
Recommended Citation
Carnicom, Elizabeth M.; Abruzzese, Jessica A.; Sidibe, Yacouba; Myers, Kenneth D.; and Tillman, Eric. "Effect of Trapping Agent and Polystyrene Chain End Functionality on Radical Trap-Assisted Atom Transfer Radical Coupling." Polymers (2014) : 2737-2751.