2- phenylethyl systems, participation

Like kact, kjeact depends upon the nature of the transferable atom. For instance, the deactivation of 1-phenylethyl radicals (structurally similar to the propagating polystyrene radicals) with the bromide complex Cu°(dNbpy)2Br (kjeact = 2.5 x lO s ) is almost 6 times faster than for the analogous chloride complex Cu°(dNbpy)2Cl (k eact = 4.3x 10 M s ). It is consequently expected and indeed observed that polymerization control is better if alkyl bromides and copper bromide-containing catalysts are used in ATRP provided that no side reactions take place in the system. However, if the alkyl halide initiator or polymeric dormant state can easily participate in nucleophilic substitution reactions, the use of chloride-based initiator and/or catalyst is advantageous due to lower reactivity of alkyl chlorides in nucleophilic substitution. For instance, the ATRP of 4-vinylpyridine using... 

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