1H and 13C NMR spectra of poly(propyl α‐bromoacrylate) and poly(methyl α‐bromoacrylate)

Abstract The 13C NMR spectra measured at 25 MHz of the methyl and propyl esters of isotactic and syndiotactic poly(α‐bromoacrylate) were sufficiently resolved to be analysed for pentad tacticity sequences. The pentad tacticity of the syndiotactic polymers prepared with free radical initiators at −40°C agreed with those calculated for Bernoullian sequence distributions based on Pr values of 0,83–0,87. The tacticities of the isotactic polymers prepared with heterogeneous catalysts were determined on the basis of these assignments. Good internal consistency was obtained between the calculated and observed pentad proportions from the quaternary and carbonyl carbon peaks in the spectra of these polymers. The order of chemical shifts for the meso and racemic dyads and tetrads in these polymers were opposite to those found in the equivalent methacrylate polymers, but as with the latter, the 13C‐T1 values were longer in the isotactic than in the syndiotactic polymers.