The kinetic and structural analyses of the polymer resulting from the Cu(0)/Me 6 -TREN-mediated polymerization of methyl acrylate (MA) initiated with methyl 2-bromopropionate (MBP) in solvents mediating different degrees of disproportionation are reported. Accurate analyses of the polymerization and of the resulting polymer demand a minimum combination of techniques that includes kinetics, GPC, 1 H NMR, and MALDI-TOF both performed before and after chainend functionalization via thio−bromo "click" chemistry and reinitiation experiments. At [MA] 0 /[MBP] 0 = 222 the use of the disproportionating solvent DMSO generated first-order kinetics and 97% active chain ends of the polymer at 89% conversion. The less disproportionating solvent MeCN produced two linear firstorder kinetics and a decrease of bromine chain-end functionality of the polymer with conversion, yielding 77% active chain ends at 89% conversion. The nondisproportionating solvent toluene, in the presence of TEMPO, produced two linear first-order kinetics with only 50% active chain ends of the polymer at 92% conversion.
High activation of polystyrene with bromine end groups (PSTY-Br) to their incipient radicals occurred in the presence of Cu(I)Br, Me 6 TREN, and DMSO solvent. These radicals were then trapped by nitroxide species leading to coupling reactions between PSTY-Br and nitroxides that were ultrafast and selective in the presence of a diverse range of functional groups. The nitroxide radical coupling (NRC) reactions have the attributes of a "click" reaction with near quantitative yields of product formed, but through the reversibility of this reaction, it has the added advantage of permitting the exchange of chemical functionality on macromolecules. Conditions were chosen to facilitate the disproportionation of Cu(I)Br to the highly activating nascent Cu(0) and deactivating Cu(II)Br 2 in the presence of DMSO solvent and Me 6 TREN ligand. NRC at room temperature gave near quantitative yields of macromolecular coupling of low molecular weight polystyrene with bromine chain-ends (PSTY-Br) and nitroxides in under 7 min even in the presence of functional groups (e.g., -, -OH, -COOH, -NH 2 , =O). Utilization of the reversibility of the NRC reaction at elevated temperatures allowed the exchange of chain-end groups with a variety of functional nitroxide derivatives. The robustness and orthogonality of this NRC reaction were further demonstrated using the Cu-catalyzed azide/alkyne "click" (CuAAC) reactions, in which yields greater than 95% were observed for coupling between PSTY-N 3 and a PSTY chain first trapped with an alkyne functional TEMPO (PSTY-TEMPO-).
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