Stereospecific radical polymerization

Radical polymerization of N-methyl-N-(2-pyridyl)acrylamide (MPyAAm) was carried out in dichloromethane at low temperatures in the presence of trifluoroacetic acid (TFA). The m dyad contents of the polymers obtained at 0°C increased linearly from 37% to 60% with increase in the [TFA]0/[MPyAAm]0 ratio from unity to 5. NMR analysis of MPyAAm-TFA mixtures in dichloromethane-d2 revealed that the favorable conformation in terms of the pyridyl group to the carbonyl group in MPyAAm switched from s-trans to s-cis by protonation. The results suggest that controlling the conformation of MPyAAm resulted in control of the stereospecificity in radical polymerization of the monomer