Quasi-Living Polymerization of Propene with an Isotactic-Specific Zirconocene Catalyst.

Propene polymerization with isotactic ( iso )-specific C ₂-symmetric rac -Me₂Si(2-Me-Benz(e)-Ind)₂ZrCl₂ ( 1 ) and rac -Me₂Si(2-Me-4-Ph-1-Ind)₂ZrCl₂ ( 2 ) were conducted under various conditions for achieving iso -specific living polymerization of propene. When Complex 1 was activated with trialkylaluminum-free modified methylaluminoxane (dMMAO) at -40 °C, the number-average molecular weight ( M n ) linearly increased against the polymerization time to reach M n = 704,000 within 15 min of polymerization, although the molecular weight distributions was broad ( M w / M n < 3). Thus, it was found that quasi-living polymerization of propene proceeded in the 1 -dMMAO system. The living nature of iso -polypropene was confirmed by the block copolymerization, where the M n value increased from 221,000 to 382,000 after the addition of 1-octene to yield the block copolymer with a melting point of 150 °C.