| Abstract: | A zerovalent nickel complex, Ni(PPh3)4, induced living radical polymerization of methyl methacrylate (MMA) in conjunction with an organic bromide as an initiator R–Br: CCl3Br, (CH3)2C(CO2Et)Br, (CH3)2C(COPh)Br] in the presence of Al(Oi-Pr)3 additive. The molecular weight distributions were narrow (M?w/M?n ～ 1.2) throughout the reactions, and the number-average molecular weights (M?n) increased in direct proportion to monomer conversion. In contrast, the polymers obtained with CCl4 in place of R–Br had broader MWDs (M?w/M?n > 2). The Al(Oi-Pr)3 additive should be added for the smooth polymerizations of MMA to occur, similarly to those with a divalent nickel bromide, NiBr2(PPh3)2. The Ni(PPh3)4-mediated living polymerization apparently proceeds via the activation of the C? Br bond from the initiators R? Br, assisted by the redox reaction of the complex between Ni(0) and Ni(I) species. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3003–3009, 1999 |
