Influence of the chemical structure of dithiocarbamates with different R groups on the reversible addition-fragmentation chain transfer polymerization

Four dithiocarbamates, carbazole-9-carbodithioic acid benzyl ester (R1), carbazole-9-carbodithioic acid naphthalen-1-ylmethyl ester (R2), 2-(carbazole-9-carbothioyl-sulfanyl)-2-methyl-propionic acid ethyl ester (R3), and (carbazole-9-carbothioylsulfanyl)-phenyl-acetic acid methyl ester (R4), were synthesized and used to the reversible addition-fragmentation chain transfer (RAFT) polymerizations of styrene (St), methyl methacrylate (MMA), and methyl acrylate (MA), respectively. The influence of chemical structure of dithiocarbamates with different R groups on the RAFT polymerizations was investigated. The results showed that the four RAFT agents were effective RAFT agents for the polymerizations of styrene or MA, and that the polymerizations were well-controlled with the characteristics of controlled/"living" polymerization. The polymerization rate of styrene with thermal initiation was markedly influenced by the chemical structures of the group R in dithiocarbamates, and decreased in the order of R3 > R2 > R4 > R1. For the polymerization of MA, the efficiency of RAFT agents was in the following order: R2-R3 > R1 > R4. However, they were not efficient enough to control the polymerization of MMA. The obtained polystyrene (PSt) with carbazole group labeled strongly absorbed UV light at 294 nm and emitted fluorescent light in N,N-dimethyl formamide (DMF). (c) 2006 Wiley Periodicals, Inc.