STEREOSPECIFIC POLYMERIZATION OF PROPYLENE IN THE PRESENCE OF HOMOGENEOUS CATALYSTS - LIGAND-MONOMER ENANTIOSELECTIVE INTERACTIONS

Syndiotactic and isotactic polypropylene have been prepared in the presence of the catalytic systems i-PrCp-1-FluZrCl2/MAO and Et(1-In)2ZrCl2/MAO. C-13-enriched Al(CH3)3 has been added to the catalysts in order to observe the stereospecificity of the initiation on metal-CH3 bonds. C-13 NMR analysis of the enriched end groups shows the contribution to the enantioselectivity of the direct interaction of the incoming monomer with the ligands of the transition metal of the true catalytic species.