A new series of zirconium metallocenes derived from partially alkylated s-indacene with potential applications in the polymerization of ethylene

Abstract

This contribution describes the synthesis and characterization of a series of zirconium metallocenes derived from partially alkylated s-indacene. The complexes [Cp∗ZrCl2-s-Ic″H] 1, [Cp∗ZrCl2-s-Ic″H] 3 and [CpZrCl2-s-Ic″H] 4 (s-Ic′H=2,6-diethyl-4,8-dimethyl-1-hydro-s-indacene; s-Ic″H=2,6-dibutyl-4,8-dimethyl-1-hydro-s-indacene) were synthesized from the monolithiated salts of s-indacene (s-Ic′H or s-Ic″H) with one equivalent of C5R5ZrCl3 (R=H, CH3). All complexes here reported were characterized by means of 1H and 13C NMR, mass spectrometry, elemental analysis. Complexes [Cp∗ZrCl2-s-Ic′H] 1 and [CpZrCl2-s-Ic′H] 2 (previously reported by NMR analysis) were characterized by X-ray diffraction. In order to gain further knowledge about their catalytic behavior, the complexes were tested in the catalysis of ethylene polymerization showing a highest activity. Complex 4 presents the highest ethylene polymerization activity than complexes 1 and 2, and 3 under the same working conditions.