ИСТИНА

The positive influence of nitrogen-containing substituent(s) in Cp-type ligand of Group 4 single-site catalysts on their polymerization performance is well-documented. One representative example is so-called “heterocenes” which contain a η5-cyclopentadienyl fragment fused to an electron-rich heterocycle, such as pyrrole. One more well-performing catalyst which was commercialized by Dow Chemical is based on titanium constrained complex containing electron-donating 1-pyrrolidinyl group in the indenyl fragment. At the same time, synthesis of indenyl metallocenes bearing NR2 substituents in pos. 5 of indene were not known. Polymerization behavior of these complexes may shed some light on an influence of electron donor substituents in indenes to catalytic performance of respective zirconocenes Thus, elaboration of reliable pathways to multisubstituted 5-NR2-indenes and respective racemic ansa-zirconocenes represents an interesting task. In this study a series of C2–symmetric SiMe2-bridged bis-indenyl zirconium complexes containing 2-methyl-4-aryl/isopropyl-5-amino/pyrrolyl-6-alkylindenyl fragments have been synthesized and unambiguously characterized. These complexes activated by MAO demonstrated high catalytic activity in homo- and heterogeneous polymerization of propylene. Moreover, the degree of electronic interaction of aminogroup in pos. 5 with indenyl ring system was tested via computational investigations, and notable influence of aminogroup on electronic structure of the complexes is witnessed.