MICROSTRUCTURE OF ISOTACTIC POLYPROPYLENE PREPARED WITH HOMOGENEOUS CATALYSIS - STEREOREGULARITY, REGIOREGULARITY, AND 1,3-INSERTION

Regioirregularly arranged units have been observed by **1**3C NMR analysis of isotactic polypropylene prepared in the presence of either racemic ethylenebis(4,5,6,7-tetrahydro-1-indenyl)dichlorozirconium or racemic ethylenebis(indenyl)dichlorozirconium and methylalumoxane. However, the stereochemical placement of the regioirregular units is controlled by the catalyst so that one can speak of more or less stereoregular placement of regioirregular units. The eta **5 ligands of zirconium affect the stereochemical and regiochemical structure of the polymer. 1,3-Propene insertion has also been observed at a relatively high polymerization temperature.