Chemical shifts relating to methyl carbon of central group in the undecad situated within an otherwise isotactic polypropylene chain were calculated by using Gamma effects

Suter and Flory's rotational polypropylene model. All meso

single

double and tetra racemic (r) defects in the undecad were designed.By comparing the chemical shifts calculated from experimental 67.8 MHz 13C-NMR spectra data indicated that the main stereo-defects are isolated rr triads in predominantly isotactic polypropylene chain and the long rrrr sequence

but do not isolated rrrr pentad distri-buted in the isotactic polypropylene chain.