Synthesis of unbridged bis(2-R-indenyl)zirconocenes containing functional groups and investigations in propylene polymerization

Five new indenyl zirconium metallocenes with 2-alkyl and 2-aryl substituent s were synthesized and characterized. For the synthesis of the ligand the d i-Grignard reagent 1,2-bis(magnesiomethyl)benzene dichloride was explored a s a synthon to 2-substituted indenes. This procedure provides access to a v ariety of functionalized 2-indenylmetallocenes such as bis(2-ferrocenylinde ne)zirconium dichloride and bis(2-adamantylindenyl)zirconium dichloride. Cr ystallographic characterization of bis[2-(4-(dimethylamino)phenyl)indenyl] zirconium dichloride revealed an anti conformation with a coplanar orientat ion of the dimethylamino substituent to the aryl ring in the solid state. T he polymerization behavior of all five zirconocene dichlorides in liquid pr opylene was studied in the presence of MAO at various temperatures, and the results were compared to those for the known catalyst system bis(2-phenyli ndenyl)zirconium dichloride/MAO (M1/MAO). The productivity of the 2-arylind ene metallocenes in propylene polymerization was on the order of 100-7000 k g of PP/((mol of Zr) h). In contrast, the (2-adamantylindenyl)metallocenes exhibited very low productivities of 6 kg PP/((mol of Zr) h) in propylene p olymerization.