Pyrrolidin-2-one structure derivatives as novel ligands for copper-based atom transfer radical polymerization (ATRP)

Abstract

(N-R)3TEDP, 1,1′-(2,2′-(2,2′-(alkylazanediyl) bis(ethane-2,1 -diyl)bis(alkylazanediyl))bis(ethane-2,1 -diyl))dipyrrolidin-2- one, with central alkyl amine and peripheral pyrrolidin-2-one structure was successfully employed as ligand in copper-based ATRP. The polymerization followed the first order kinetic and the molecular weights of PMMA increased linearly with monomer conversion. Although the Mn of products obtained by SEC was higher than the theoretic ones, the distribution of molecular weight was narrow (<1.4). By introducing deactivator CuBr 2, the polymerization rate of the ATRP catalyzed by CuBr/(N-butyl)3TEDP decreased dramatically, but the control was improved (Mw/Mn = 1.22). Using mixed halide initiation system (CuCl/EBiB), the Mn of synthesized PMMA was more close to the calculated value with much lower molecular weight distribution (M w/Mn = 1.15). The effect of temperature was investigated and the low ΔHθeq value (21.38kJ·mol-1) was derived from the Arrhenius plot. The alkyl substitute of (N-R) 3TEDP had profound effect on the CuBr-catalyzed ATRP of MMA, due to the steric effect introduced by their bulky size. The activity of these ligands in the ATRP showed the following order: C12 « C4 ∼ C6 ∼ C8, in the abbreviate form of (N-R)3TEDP. © 2008 The Society of Polymer Science.