Micro- and macroconformation of macromolecules

Summary

From the temperature dependence of ¹³C-NMR chemical shift measurements under fast exchange conditions, using the methyl carbon atom as indicator, it was concluded that for erythrodiisotactic head-to-head tail-to-tail polypropylenes the temperature dependence of the conformers around the methine-methine bond may be analyzed quantitatively. In the present paper the ¹³C-NMR analysis has been expanded to inverted polypropylenes of arbitrary ditacticity. Methyl, methylene as well as methine resonances have been taken into account for assignements. Conformational influences on the ¹³C-NMR spectrum are discussed as well as the relevance of low molecular weight models for diads.