Proton and carbon NMR spectra of alternating and statistical styrene-methyl methacrylate copolymers revisited

The a-Me proton NMR resonances of the 3 different configurational Me methacrylate-centered triad sequences of alternating styrene (I)-Me methacrylate (II) copolymers are reassigned. Literature assignments are inconsistent with data and each other. Selective decoupling expts. are carried out to assign the C NMR resonances of the a-Me groups of alternating I-II copolymers. Subsequently, the C resonances of the arom. C1 and a-Me literature assignments of the statistical I-II copolymers are reconsidered and reassigned in terms of configurational triad sequences