Mn₂(CO)₁₀-Induced Controlled/Living Radical Copolymerization of Methyl Acrylate and 1-Hexene in Fluoroalcohol: High α-Olefin Content Copolymers with Controlled Molecular Weights

A highly active manganese complex [Mn 2 (CO) 10 ] efficiently induced the controlled/living radical copolymerizations of a conjugated polar vinyl monomer, methyl acrylate (MA), and an unconjugated nonpolar olefin, 1-hexene (1-Hex), in the presence of ethyl 2-iodoisobutyrate (EMA−I) as an initiator under weak visible light at 40 °C to give the copolymers with controlled molecular weights. The further use of protic fluoroalcohols as solvents enhanced the copolymerization without losing the molecular weight control to result in a high 1-Hex content up to 50 mol %, for which the predominant alternating sequences were confirmed by the 13 C NMR analysis of the copolymers. The kinetic analysis of the copolymerizations revealed an increase in the reactivity of the MA-radical to the 1-Hex monomer in the fluoroalcohol [1/ r MA = 0.49 in (CF 3 ) 2 CHOH vs 0.081 in toluene], which can be attributed to the 1:1 hydrogen-bonding interaction between the MA unit and the fluoroalcohol as suggested by the 13 C NMR analysis of the MA−fluoroalcohol mixtures [ K assn = 2.21 L/mol for (CF 3 ) 2 CHOH]. Thus, a combination of a highly active Mn 2 (CO) 10 catalyst and a protic fluoroalcohol solvent is effective for the alternating controlled/living radical copolymerization of acrylic monomers and α-olefins.