Living radical polymerization with reversible addition-fragmentation chaintransfer (RAFT polymerization) using dithiocarbamates as chain transfer agents

Living radical polymerization with reversible addition-fragmentation chain transfer (RAFT polymerization) can be achieved with the use of dithiocarbam ate derivatives that have the nonbonded electron pair of the nitrogen inclu ded as part of an aromatic system. These compounds have been shown to be hi ghly effective in RAFT polymerization of styrene and (meth)acrylate esters to produce polymers of predetermined molecular weight and narrow polydisper sity (usually <1.2). By contrast, simple N,N-dialkyl dithiocarbamates (thos e compounds previously described as "photoiniferters") are ineffective as R AFT agents. The reasons for the different behavior are discussed.