The microstructure of the oils produced from iPP are complex. A representative quantitative C{ 1 H} NMR spectra of oils in C6D6 at 25 o C are shown in Figure . Virtually indistinguishable 13 C{ 1 H} NMR spectra are obtained for the other oils described above, though the oils formed in the absence of H2 contain signals for internal olefins. These spectra contain a dispersion of -CH2-, -CH-, and -CH3 signals consistent with complete loss of diastereoselectivity. These spectra also contain signals between ~30 -40 ppm that are assigned to regioirregular errors that appear through chain straightening or related processes under the reaction conditions. Integration of the -CH2-and regioirregular error signals indicate that the ratio of C3H6:regioirregular error is ~1:2, or ~66 % of the main chain in these oils are straightened. Signals for oxygenate functionalities are not present in any of the 13 C{ 1 H} NMR spectra for any of the oils.