Effect of Substituents on Radical Stability in Reversible Addition Fragmentation Chain Transfer Polymerization: An ab Initio Study

The substituents effects on radical stability in the reversible addition fragmentation chain transfer (RAFT) polymerization process was investigated using high level ad initio molecular orbital calculations. The RAFT-adduct radicals were stabilized by electron donation from the two sulfur substituents. It was observed that the lone pair donor Z-substituents had smaller effect on radical stability. The results show that the substituent effects on the RAFT agents were qualitatively different and the agents were srongly stabilized by the lone pair donor Z-substituents.