A New C2-symmetric {SBI}-type zirconocene complex incorporating electron-donating substituents for highly productive, highly isoselective homo- and copolymerization of propylene

• SBI-type metallocene featuring electron-donating OMe substituents. • Dual locking (“hard” and “soft”) enforces ultrarigid ligand geometry. • Achieves high activity, high molecular weights, and very high isotacticity. The new Me 2 Si-bridged bis(indenyl) proligand {Me 2 Si(2-Me-4-(3’,5’- t Bu 2 -4’-OMe-C 6 H 2 )-5-OMe-6- t Bu-Ind) 2 }H 2 ( 1 ), incorporating bulky and electron-donating substituents both on the indene platform and the 4-aryl-indenyl moiety, was prepared. The corresponding C 2 -symmetric ansa -zirconocene complex rac -{Me 2 Si(2-Me-4-(3’,5’- t Bu 2 -4’-OMe-C 6 H 2 )-5-OMe-6- t Bu-Ind) 2 }ZrCl 2 ( 1-ZrCl 2 ) was synthesized and isolated in pure racemic form, and characterized by NMR spectroscopy, mass spectrometry and X-ray crystallography. The zirconocene complex, once activated with MAO in toluene solution, exhibited propylene polymerization activities at 60 °C up to 217,000 kg(PP).mol(Zr) −1 .h −1 , affording highly isotactic polypropylene ( i PP) with [ m ] 4 up to >99 mol % and T m up to 160.1 °C. Also, the SiO 2 -MAO-supported metallocene complex ( supp -1-ZrCl 2 ) was evaluated in slurry bulk propylene polymerization at 70 °C, producing i PP with [ m ] 4 content of 99.4−99.5 mol % and low amounts of regiodefects (0.4−0.5 mol %) ( T m up to 159.4 °C), with productivities up to 980,000 kg(PP)·mol(Zr) −1 ·h −1 . Also, polymerization of propylene in the presence of ethylene under slurry conditions allowed obtaining isotactic-rich i PP- co -E copolymers with very high activities up to 3,420,000 kg(PP)·mol(Zr) −1 ·h −1 . The new materials contained ca. 1 wt % of the incorporated ethylene units and featured melting transitions up to 147.5 °C.