Synthesis, characterization, and catalytic properties of bis[alkylindenyl]-, bis[alkenylindenyl]- and [alkenylindenyl(cyclopentadienyl)]zirconium dichloride complexes

Abstract

4,7-Dimethylindenyl lithium or 2,4,7-trimethylindenyl lithium reacts with 1-bromobutane, 1-chloro-2-propene, or 1-bromo-3-methyl-2-butene to give 3-butyl-4,7-dimethyl-1 H-indene ( 1), 3-(2-propene-1-yl)-2,4,7-trimethyl-1 H-indene ( 2), or 3-(3-methyl-2-butene-1-yl)-2,4,7-trimethyl-1 H-indene ( 3), respectively. Deprotonation of 1– 3 with n-butyl lithium yields the lithium salts 1a– 3a. The reactions of 1a– 3a and of [1-(4-pentene-1-yl)indenyl]lithium ( 4a) with zirconiumtetrachloride produce the complexes bis[1-butyl-4,7-dimethylindenyl]- ( 1b), bis[1-(2-propene-1-yl)-2,4,7-trimethyl-indenyl]- ( 2b), bis[1-(3-methyl-2-butene-1-yl)-2,4,7-trimethylindenyl]- ( 3b) or bis[1-(4-pentene-1-yl)indenyl]zirconium dichloride ( 4b). The reaction of cyclopentadienylzirconium trichloride with [2-(3-butene-1-yl)-4,7-dimethylindenyl]lithium or [2-(4-pentene-1-yl)-4,7-dimethylindenyl]lithium affords the mixed complexes [2-(3-butene-1-yl)-4,7-dimethylindenyl(cyclopentadienyl)]zirconium dichloride ( 5c) or [2-(4-pentene-1-yl)-4,7-dimethylindenyl(cyclopentadienyl)]zirconium dichloride ( 6c). All new compounds were characterized by elemental analysis, 1H- and 13C{ 1H}-NMR spectroscopy as well as by mass spectrometry. In addition, single-crystal X-ray structural analysis was done for 3b. The complexes 1b– 4b, 5c, and 6c were tested as catalysts for the homopolymerization and copolymerization of ethene and propene and the results were compared to those of analogous compounds.