Abstract
Two pyridyl-imine ligands, N,N-dimethyl-N′-((pyridin-2-yl)methylene)- ethane-1,2-diamine (paenMe <sub>2</sub> ) and N,N-diethyl-N′-((pyridin-2-yl) methylene)-ethane-1,2-diamine (paenEt <sub>2</sub> ), have been applied to AGET and SARA ATRP of styrene and methyl methacrylate. The polymeric products showed a narrow molecular weight distribution (M <sub>w</sub> /M <sub>n</sub> = 1.16-1.28) and a molecular weight that not only increased linearly with monomer conversion (>70%) but also matched to the theoretical value. The performance of Cu <sup>II</sup> (paenMe <sub>2</sub> )Br <sub>2</sub> and Cu <sup>II</sup> (paenEt <sub>2</sub> )Br <sub>2</sub> in AGET ATRP was almost the same and thus the steric effect between these two complexes was not significant. The activation rate constant (k <sub>act</sub> ) of Cu <sup>I</sup> (paenMe <sub>2</sub> )Br with PEBr was measured as 7.96 × 10 <sup>-3</sup> M <sup>-1</sup> s <sup>-1</sup> and the deactivation rate constant (k <sub>deact</sub> ) was estimated as 2.8 × 10 <sup>5</sup> M <sup>-1</sup> s <sup>-1</sup> . This kinetic measurement indicated that the improved control efficiency of pyridyl-imine based catalysts in AGET and SARA ATRP should be attributed to the high deactivator/activator (Cu <sup>II</sup> species/Cu <sup>I</sup> species) ratio that relatively enhanced the deactivation rate and lowered the radical concentration to minimize the influence of radical termination and other side reactions. © 2013 Elsevier Ltd. All rights reserved.