Stereoerror Formation in the Polymerization of Propylene Catalyzed by a Titanium Bis(benzamidinate) Dichloride Complex Activated by MAO

A new mechanism for the formation of stereoerrors during the polymerization of propylene, promoted by the C 2 -symmetric benzamidinate titanium complex 1, has been observed at low and high pressure using unlabeled and 2- d -labeled propylene. The use of deuterated propylene induces higher tacticities and molecular weights of the resulting polymers. At high pressure, the polymerization of the deuterated propylene induces faster insertion and termination processes. The new epimerization mechanism, which may be accompanied by a C H 2 /C D (Me) exchange, is presented.